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The emission properties of a single Si microdisk resonator with a deterministically embedded GeSi quantum dot (QD) stack have been investigated. The results demonstrate selective excitation of different modes of the resonator depending on the position of QDs. The photoluminescence (PL) spectrum changes dramatically depending on the location of the QDs in the resonator. For the central QD position, the excitation of low Q-factor Mie modes with high field concentration in the center of resonator results in the appearance of a broad PL band. When the stack of QDs is shifted from the center to the edge of the Si resonator, the quenching of this PL band is observed and narrow PL peaks corresponding to whispering gallery modes (WGMs) appear in the PL spectrum. It is found that resonator modes can be excited not only by QDs but also by the radiation of the wetting layer. It is shown that a GeSi island on the top of the QD stack, not covered by silicon, can play the role of a nanoantenna, redirecting radiation to the upper half-space, which is especially important for WGMs that usually radiate sideways. [ABSTRACT FROM AUTHOR]

In a class of high quality (Q-) factor dielectric resonators with low radiative losses, including popular whispering-gallery mode (WGM) resonators with high azimuthal mode numbers, due to high confinement of modal field in dielectric, the Q-factor is limited by the value of inverse dielectric loss tangent of dielectric material. Metal enclosures necessary for device integration only marginally affect the Q-factor while eliminating the residual radiative loss and allowing the optimization of input and output coupling. While very high Q-factors ∼ 200 000 are available in sapphire WGM resonators in X-band, at millimeter wave frequencies increasing dielectric loss limits the Q-factor to much smaller values, e.g. ∼50000 and ∼25000 for quasi-TE and quasi-TM modes, correspondingly, at 36 GHz. The use of distributed Bragg reflection (DBR) principle allows to push modal energy outside dielectric while also isolating it from Joule losses in metallic enclosure walls. Very high Q ∼ 600 000 > --> t g δ has been demonstrated in X-band [C. A. Flory and R. C. Taber, IEEE Trans. Ultrason., Ferroelectr., Freq. Control 44, 486–495 (1997).] at the expense of impractically large dimensions. In this work, we report on the assembly and testing of a compact Ka-band sapphire distributed Bragg reflector cavity characterized with Q-factor seven times larger than one predicted by the material's dielectric loss at the frequency of interest. An intrinsic Q-factor of ∼ 200 000 is demonstrated at 36 GHz for the lowest order TM-mode of a sapphire DBR. The resonator has 50 cm 3 volume, smaller than previously demonstrated DBRs. [ABSTRACT FROM AUTHOR]

A review of the recent developments in the field of lasing with liquid crystals (LCs) is presented. After an introduction into the principle of lasing the different relevant liquid crystal phases to the field are introduced, namely, the nematic and chiral nematic phase, Blue Phases, twist grain boundary and ferroelectric liquid crystals. The classic examples of liquid crystal lasing are shortly discussed, together with a variety of possibilities for tuning the lasing wavelength, before the modern trends in LC lasing are discussed in detail. These are particularly random lasers, where the effects of nanoparticles, quantum dots and solitons are highlighted, as well as localized surface plasmon resonance. Other modern laser systems that have attracted recent interest, white lasers, whispering gallery mode lasers and those with biological materials, for example, cellulose nanocrystals, are also introduced and the latest developments outlined. [ABSTRACT FROM AUTHOR]

We present experimental observations of dilute ion spin ensemble defects in a low-loss single crystal cylindrical sample of CaWO4 cooled to 30 mK in temperature. Crystal field perturbations were elucidated by constructing a dielectrically loaded microwave cavity resonator from the crystal. The resonator exhibited numerous whispering gallery modes with high Q-factors of up to 3 × 10 7 , equivalent to a loss tangent of ∼ 3 × 10 − 8 . The low loss allowed precision multi-mode spectroscopy of numerous high Q-factor photon–spin interactions. Measurements between 7 and 22 GHz revealed the presence of Gd3+, Fe3+, and another trace species, inferred to be rare-earth, at concentrations on the order of parts per billion. These findings motivate further exploration of prospective uses of this low-loss dielectric material for applications regarding precision and quantum metrology, as well as tests for beyond standard model physics. [ABSTRACT FROM AUTHOR]

In a molecule formed by two atoms, energy difference between bonding and antibonding orbitals depends on distance between the two atoms. However, exploring molecular orbitals of two natural atoms with tunable distance has remained an outstanding experimental challenge. Graphene quantum dots can be viewed as relativistic artificial atoms, thus offering a unique platform to study molecular physics. Here, through scanning tunneling microscope, we create and directly visualize the formation process of relativistic artificial molecules based on two coupled graphene quantum dots with tunable distance. Our study indicates that energy difference between the bonding and antibonding orbitals of the lowest quasibound state increases linearly with inverse distance between the two graphene quantum dots due to the relativistic nature of the artificial molecule. For quasibound states with higher orbital momenta, the coupling between these states leads to half-energy spacing of the confined states because the length of the molecular-like orbit is approximately twice that of the atomic-like orbit. Evolution from ring-like whispering-gallery modes in the artificial atoms to figure-eight orbitals in the artificial molecules is directly imaged. The ability to resolve the coupling and orbitals of the relativistic artificial molecule at the nanoscale level yields insights into the behavior of quantum-relativistic matter. Graphene quantum dots have electronic structures resembling these of atoms. Here, the authors use two of these compounds to construct artificial molecules and study their electronic properties at tunable distances. [ABSTRACT FROM AUTHOR]

Quantum well nanolasers usually show single‐mode lasing, as gain saturation suppresses emissions in other modes. In contrast, for whispering gallery mode microdisk lasers with GaN quantum wells as active material, above threshold multimode laser emission is observed. This intriguing emission feature is manifested in the fact that several modes simultaneously show the characteristic kink in the input–output curve at the onset of lasing. A quantum theory for nanolasers is used to support the experimental finding and to analyze this behavior in the presence of gain saturation. Coupling effects between neighboring modes are identified as the origin of multimode lasing, which initiate photon exchange between modes via population pulsations similar to classical wave‐mixing effects. A reduction of this type of mode coupling with increasing mode spacing is demonstrated. The results can pave the way for multimode application of nanolasers in integrated photonic circuits. [ABSTRACT FROM AUTHOR]

Significant research accomplishments have been made so far for the development and application of ZnO nanomaterials in enhanced optical biodetection. The unparalleled optical properties of ZnO nanomaterials and their reduced dimensionality have been successfully exploited to push the limits of conventional optical biosensors and optical biodetection platforms for a wide range of bioanalytes. ZnO nanomaterial-enabled advancements in optical biosensors have been demonstrated to improve key sensor performance characteristics such as the limit of detection and dynamic range. In addition, all nanomaterial forms of ZnO, ranging from 0-dimensional (0D) and 1D to 2D nanostructures, have been proven to be useful, ensuring their versatile fabrication into functional biosensors. The employment of ZnO as an essential biosensing element has been assessed not only for ensembles but also for individual nanomaterials, which is advantageous for the realization of high miniaturization and minimal invasiveness in biosensors and biodevices. Moreover, the nanomaterials' incorporations into biosensors have been shown to be useful and functional for a variety of optical detection modes, such as absorption, colorimetry, fluorescence, near-band-edge emission, deep-level emission, chemiluminescence, surface evanescent wave, whispering gallery mode, lossy-mode resonance, surface plasmon resonance, and surface-enhanced Raman scattering. The detection capabilities of these ZnO nanomaterial-based optical biosensors demonstrated so far are highly encouraging and, in some cases, permit quantitative analyses of ultra-trace level bioanalytes that cannot be measured by other means. Hence, steady research endeavors are expected in this burgeoning field, whose scientific and technological impacts will grow immensely in the future. This review provides a timely and much needed review of the research efforts made in the field of ZnO nanomaterial-based optical biosensors in a comprehensive and systematic manner. The topical discussions in this review are organized by the different modes of optical detection listed above and further grouped by the dimensionality of the ZnO nanostructures used in biosensors. Following an overview of a given optical detection mode, the unique properties of ZnO nanomaterials critical to enhanced biodetection are presented in detail. Subsequently, specific biosensing applications of ZnO nanomaterials are discussed for ~40 different bioanalytes, and the important roles that the ZnO nanomaterials play in bioanalyte detection are also identified. [ABSTRACT FROM AUTHOR]

Whispering‐gallery‐mode (WGM) resonators composed of organic and/or inorganic materials have been used in highly sensitive sensors, logic gates, and miniaturized lasers because of the total internal reflection of photons. However, most fabrication methods have been limited to bottom‐up self‐assembly; whereas, a facile top‐down process is preferable. Here, a wet‐process fabrication of WGM resonators mixed with 5 µm‐diameter spherical silica‐gels and various π‐conjugated compounds is demonstrated. The materials are fabricated by dip‐coating photoluminescent molecules onto submicron‐scale silica‐gel spheres. The shapes and large specific surface areas of templates are maintained before and after coating, and the coated molecules are uniformly distributed. The hybrid spheres provided WGM photoluminescence spectra based on the total internal reflection of photoluminescence in the sphere. The hybrid spheres are applicable as WGM sensors because of their large specific surface area (>4 × 102 m2 g−1). In particular, gas sensing of toluene, which has been used as a standard for environmental contamination, and found that the WGM photoluminescence peaks are shifted by 5 nm is demonstrated. The detection resolution is calculated to be several hundred ppm level. The hybrid spheres can be placed or transferred onto various surfaces without micromanipulation, which suggested a wide range of possible applications. [ABSTRACT FROM AUTHOR]

Topological phononic cavities, such as ring resonators with topological whispering gallery modes (TWGMs), offer a flexible platform for the realization of robust phononic circuits. However, the chiral mechanism governing TWGMs and their selective routing in integrated phononic circuits remain unclear. This work reveals, both experimentally and theoretically, that at a phononic topological interface, the elastic spin texture is intricately linked to, and can be explained through a knowledge of, the phonon eigenmodes inside each unit cell. Furthermore, for paired, counterpropagating TWGMs based on such interfaces in a waveguide resonator, this study demonstrates that the elastic spin exhibits locking at discrete frequencies. Backed up by theory, experiments on kHz TWGMs in thin honeycomb‐lattice aluminum plates bored with clover‐leaf shaped holes show that together with this spin‐texture related angular‐momentum locking mechanism at a single topological interface, there are triplicate parity‐frequency‐space selective wave routing mechanisms. In the future, these mechanisms can be harnessed for the versatile manipulation of elastic‐spin based routing in phononic topological insulators. [ABSTRACT FROM AUTHOR]

Optical microcavities, particularly whispering gallery mode (WGM) microcavities enhanced by plasmonic nanorods, are emerging as powerful platforms for single‐molecule sensing. However, the impact of optical forces from the plasmonic near field on analyte molecules is inadequately understood. Using a standard optoplasmonic WGM single‐molecule sensor to monitor two enzymes, both of which undergo an open‐to‐closed‐to‐open conformational transition, the work done on an enzyme by the WGM sensor as atoms of the enzyme move through the electric field gradient of the plasmonic hotspot during conformational change has been quantified. As the work done by the sensor on analyte enzymes can be modulated by varying WGM intensity, the WGM microcavity system can be used to apply free energy penalties to regulate enzyme activity at the single‐molecule level. The findings advance the understanding of optical forces in WGM single‐molecule sensing, potentially leading to the capability to precisely manipulate enzyme activity at the single‐molecule level through tailored optical modulation. [ABSTRACT FROM AUTHOR]

Crystalline whispering gallery mode resonators (WGMRs) have been shown to facilitate versatile sources of quantum states that can efficiently interact with atomic systems. These features make WGMRs an efficient platform for quantum information processing. Here, we experimentally show that it is possible to generate polarization entanglement from WGMRs by using an interferometric scheme. Our scheme gives us the flexibility to control the phase of the generated entangled state by changing the relative phase of the interferometer. The S value of Clauser–Horne–Shimony–Holt's inequality in the system is 2.45 ± 0.07, which violates the inequality by more than six standard deviations. [ABSTRACT FROM AUTHOR]

The layer-by-layer (LbL) assembling of oppositely charged polyelectrolytes was studied using semi-synthetic polysaccharide derivatives, namely the polycations 6-aminoethylamino-6-deoxy cellulose (ADC) and cellulose (2-(ethylamino)ethylcarbamate (CAEC), as well as the polyanion cellulose sulfate (CS). The synthetic polymers poly(allylamine) (PAH) and poly(styrene sulfonate) (PSS) were employed as well for comparison. The stepwise adsorption process was monitored by whispering gallery mode (WGM) experiments and zeta-potential measurements. Distinct differences between synthetic- and polysaccharide-based assemblies were observed in terms of the quantitative adsorption of mass and adsorption kinetics. The LbL-approach was used to prepare µm-sized capsules with the aid of porous and non-porous silica particle templates. The polysaccharide-based capsule showed a switchable permeability that was not observed for the synthetic polymer materials. At ambient pH values of 7, low-molecular dyes could penetrate the capsule wall while no permeation occurred at elevated pH values of 8. Finally, the preparation of protein-loaded LbL-capsules was studied using the combination of CAEC and CS. It was shown that high amounts of protein (streptavidin and ovomucoid) can be encapsulated and that no leaking or disintegration of the cargo macromolecules occurred during the preparation step. Based on this work, potential use in biomedical areas can be concluded, such as the encapsulation of bioactive compounds (e.g., pharmaceutical compounds, antibodies) for drug delivery or sensing purposes. [ABSTRACT FROM AUTHOR]

With the aid of 3D full‐field finite difference time–domain simulations, model configurations for CsPbI3$\left(\text{CsPbI}\right)_{3}$ thin‐film solar cell devices that include periodically arranged TiO2$\left(\text{TiO}\right)_{2}$ microspheres, exhibiting resonating whispering gallery modes (WGMs), are proposed. The TiO2$\left(\text{TiO}\right)_{2}$ microspheres present, either immersed in perovskite or coated with perovskite layer, between the electron‐ and hole‐transport layers show enhanced current‐conversion efficiency. The presence of WGMs lead to enhancement in the absorption of CsPbI3$\left(\text{CsPbI}\right)_{3}$ layer. The incoming electromagnetic wave couples with TiO2$\left(\text{TiO}\right)_{2}$ microsphere and forms confined resonating modes. Different designs are examined for deciding the appropriate position of WGM exhibiting spheres with respect to thin‐film perovskite solar cell (PSC) featuring back reflector and optimized antireflectance coating. Since the incoupling element is lossless, energy stored in microspheres is absorbed efficiently by the underlying active material. This directly contributes to the increment in the current density of the solar cell. Thus, the devices show a higher current density of 23.62 mA cm−1, while that in planar solar cell device shows current density of 13.68 mA cm−1, for the same thickness of perovskite layer. This leads to more than 70% enhancement in the short‐circuit current density than the conventional PSCs device of similar size. [ABSTRACT FROM AUTHOR]

Low dimensional ZnO-based materials have drawn much attention for the past few decades due to their unique electronic and optical properties and potential applications in optoelectronic devices. In this Tutorial, we will cover the past and the latest developments in ZnO thin films and micro/nanostructures in terms of excitonic and related lasing processes. First, we give a brief overview of structural and band properties of ZnO along with the linear optical and excitonic properties. Second, we introduce a feedback mechanism for lasing in various forms of ZnO, ranging from nanoparticles to nanowires, nanodisks, and thin films. As for the feedback mechanism, detailed descriptions are given to random lasing, Fabry–Pérot lasing, and whispering gallery mode lasing. Third, we discuss possible gain mechanisms, i.e., excitonic gain and electron–hole plasma (EHP) gain, in ZnO. A special interest is also devoted to the Mott carrier density, which is a crucial parameter to distinguish between excitonic and EHP contributions to lasing. Lastly, recent developments on exciton–polariton lasers based on ZnO microcavities are introduced. [ABSTRACT FROM AUTHOR]

Whispering gallery mode resonators (WGMRs) have garnered significant interest due to their potential applications in the fields of electro-optic modulation and microwave to optical photon conversion. In this study, we have leveraged an electro-optic crystal, lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT), to fabricate a high-quality WGMR. Our investigation revealed that the crystal composition used in this work is 0.24PIN-0.45PMN-0.31PT, and each element of the whole sample is homogeneously distributed. The dielectric properties of the sample revealed the necessity of limiting the temperature and external electric field frequency to below 100 °C and 106 Hz, respectively. The obtained optical quality factor value (Q value) of the resonator is ∼0.7 × 105. Impressively, our resonator could be conveniently tuned by exploiting the enormous inverse piezoelectric effect d31 of the crystal, thereby alleviating the need for precise fabrication. Furthermore, a theoretical analysis of our resonator revealed that a calculated resonance wavelength shift is within a broad range of 2.16 nm. Intriguingly, if the surface roughness of the resonator is reduced tenfold, we can increase the calculated Q value dependent on surface scattering by 104. Our finding showcases the tremendous potential of the PIN-PMN-PT crystal-based WGMR as versatile building blocks for a variety of applications in the burgeoning field of photonic technology. [ABSTRACT FROM AUTHOR]

Interlayer excitons in two-dimensional semiconductor heterostructures show suppressed electron–hole overlap resulting in longer radiative lifetimes as compared to intralayer excitons. Such tightly bound interlayer excitons are relevant for important optoelectronic applications, including light storage and quantum communication. Their optical accessibility is, however, limited due to their out-of-plane transition dipole moment. In this work, we design a complementary metal–oxide–semiconductor-compatible photonic integrated chip platform for enhanced near-field coupling of these interlayer excitons with the whispering gallery modes of a microresonator, exploiting the high confinement of light in a small modal volume and high-quality factor of the system. Our platform allows for highly selective emission routing via engineering an asymmetric light transmission that facilitates efficient readout and channeling of the excitonic valley state from such systems. [ABSTRACT FROM AUTHOR]

In this work, we discuss and experimentally investigate the whispering gallery modes (WGMs) in a 500 μm radius silicon sphere. We begin by reviewing the basics of WGM resonators, followed by simulations and experimental results obtained with the aforementioned silicon spherical WGM resonator. The recorded WGM signatures in the transmission and scattering spectra excited, in the near-infrared (near-IR) region, agree well with the simulations. Thermo-optic tuning of these WGMs is achieved by introducing a pump laser in the violet-blue region. Red-shifts in wavelength are observed, which increase with the increase in the pump power. A shift of 0.63 nm is observed at a pump power of 6.32 mW. We also study switching by analysing the transient response of the WGM spectra. The measured WGMs exhibit high quality factors ($Q\sim 10^5$Q∼105), which along with the aforesaid tunability, demonstrates the potential of spherical silicon resonator as a platform for photonic applications, e.g. sensing and communication. In summary, this work contributes towards the understanding of the fundamental physics of WGMs and provides insights into silicon WGM resonators. [ABSTRACT FROM AUTHOR]

This paper details the fabrication of GaN-based microdisks with a single porous n-GaN layer positioned beneath the multiple quantum wells region on a modified green light-emitting diode epiwafer. Simulations of the longitudinal light field distribution reveal effective confinement of the light field within the multiple quantum wells region due to the presence of the single porous layer. The porous layer also demonstrates sufficient conductivity as determined through calculations and serves as an effective method for thermal dispersion. Under optical pumping, all microdisks exhibit clear whispering gallery mode (WGM) lasing at room temperature, with the lowest threshold of 13.50 μJ/cm2 achieved in a 2-μm-diameter microdisk. These findings suggest that integrating the single porous layer into GaN microdisks is a highly promising approach for achieving high-efficiency WGM micro-laser diodes with effective electrical injection and heat dispersion. [ABSTRACT FROM AUTHOR]

The paper is devoted to the mathematical description of the whispering gallery waves modulated by amplitude and frequency. Space-time ray method for this problem is developed. [ABSTRACT FROM AUTHOR]

A new concept of surface waves of interference nature is described in detail for the case of creeping waves propagating along a smooth strictly concave surface embedded in 3D Euclidean space. In numerous papers devoted to whispering gallery and to creeping waves, it was assumed that they propagate along boundaries formed by smooth plane curves. However, the process of surface wave propagation along smooth surfaces is much more complicated than along plane curves. Indeed, the surface waves slide along geodesic lines on the surface where they typically form numerous caustics and that, in turn, generates singularities in the wave field asymptotics. In addition, the geodesic lines themselves are not plane curves in 3D and therefore their torsion has to be taken into account. Our approach allows us to resolve both of these specific problems of wave propagation along smooth surfaces embedded in ℝ3. It is based on the consideration of the geodesic flow on the surface, which is associated with the surface wave generated by a source. For each geodesic line, we construct an asymptotic solution of the Helmholtz equation localized in a tube vicinity of the geodesic line and having no singularities on caustics. The surface wave under consideration is then presented as a superposition (integral) of the localized solutions. [ABSTRACT FROM AUTHOR]

In this work we compute the resonant wavelengths of whispering gallery modes for bulk-fused silica microspheres taking into consideration the material chromatic dispersion. This is done by following two approaches: solving the exact characteristic equation and solving the nonlinear equations that result from the asymptotic approximations for a wavelength-dependent refractive index. Similar results with both methods are obtained with differences below 1%. Nevertheless, important differences are found between the resonant wavelengths computed for a non-dispersive and a dispersive material. We compute the free spectral range and the quality factor, and make a comparison between the variable index and the constant index cases. Our results show that the quality factor is unaffected by chromatic dispersion. However, there are differences of significant relevance in the case of the free spectral range. Our work could be useful as a pathway for designing microspheres for different applications. [ABSTRACT FROM AUTHOR]

Ultra-sensitive sensors based on the resonant properties of whispering gallery modes (WGMs) can detect fractional changes in nanoscale environments down to the length and time scales of single molecules. However, it is challenging to isolate single-molecule signals from competing noise sources in experiments, such as thermal and mechanical sources of noise, and—at the most fundamental level—the shot noise limit of classical light. Additionally, in contrast to traditional bulk refractive index measurements, analyzing single-molecule signals is complicated by the localized nature of their interactions with nanoscale field gradients. This perspective discusses multifaceted solutions to these challenges, including the use of quantum light sources to boost the signal-to-noise ratio in experiments and leveraging the power of supercomputers to predict the electronic response of molecules to WGM optoplasmonic fields. We further discuss the role of machine learning in WGM sensing, including several advanced models that can predict molecular polarizability and solvent effects. These advancements in WGM spectroscopy and computational modeling can help to decipher the molecular mechanics of enzymes, enable studies of catalysis on the nanoscale, and probe the quantum nature of molecules. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling has emerged as a promising green technology for the thermal management of buildings, vehicles, textiles, and electronics. Typically, both high solar reflectance and high thermal emissivity are prerequisites to achieve sufficient daytime cooling. However, colored radiative cooling materials are facing the dilemma of introducing visible light absorption, leading to challenges in balancing cooling and aesthetic demands. Here, three colored bilayer radiative cooling coatings, each comprised of a white base layer and a colored top layer with fluorescence enhancement are fabricated. Three phosphors (Sr2Si5N8:Eu2+, Y3Al5O12:Ce3+, and (Ba,Sr)SiO4:Eu2+) are employed with respective photoluminescence quantum yields (PLQYs) of 81%, 95.8%, and 91.0% as the colored pigment in the top layer. To mitigate the contradiction between coloration and solar reflectance, SiO2 microspheres are introduced into the top layer and utilize their Mie‐resonance‐based multiple scattering to increase the photoluminescent (PL) properties of the phosphors, which jointly boosts the effective solar reflectance (ESR) of the top layer. As a result, the three bilayer coatings exhibit soft colors while achieving subambient cooling with temperature drops of up to 1.5 °C. This fluorescence‐enhancement strategy may pave the way for preparing highly efficient radiative cooling coatings with tunable colors. [ABSTRACT FROM AUTHOR]

High-quality-factor (Q) optical microcavities have attracted extensive interest due to their unique ability to confine light for resonant circulation at the micrometer scale. Particular attention has been paid to optical whispering-gallery mode (WGM) microcavities to harness their strong light–matter interactions for biological applications. Remarkably, the combination of high-Q optical WGM microcavities with microfluidic technologies can achieve a synergistic effect in the development of high-sensitivity optofluidic sensors for many emerging biological analysis applications, such as the detection of proteins, nucleic acids, viruses, and exosomes. They can also be utilized to investigate the behavior of living cells in human organisms, which may provide new technical solutions for studies in cell biology and biophysics. In this paper, we briefly review recent progress in high-Q microcavity-based optofluidic sensor technologies and their applications in biological analysis. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to particle detection using an active microresonator operating in the transparency regime. Simulations demonstrate that when particles interact with the microresonator surface, they induce optical losses. To compensate for these losses, the optical gain is amplified to restore the transparency regime. Simulation results show a linear relationship between nanoparticle concentration and the pump power required to compensate for optical losses. By the use of microresonator with a very high quality factor, this approach offers an accurate and sensitive method for detecting nanoparticles, without the need for complex equipment. [ABSTRACT FROM AUTHOR]

Corresponding to the different phase‐shifts of the interference modes, the whispering gallery mode resonator‐based Fano resonance exhibits a variety of unique spectral lineshapes that can be applied to sensing, optical signal processing, and so on. However, most approaches to lineshape tuning aim to alter the propagation phase‐shift or coupling strength, and generally suffer from relatively low efficiency and limited tuning range. In this paper, with a carefully designed waveguide‐taper coupled micro‐ring resonator structure and the assistance with the grating‐coupler, for the first time a near full‐lineshape selectivity of the Fano resonance is demonstrated in two isolated tuning dimensions of the frequency and transverse space, which means arbitrary lineshapes including the Lorentzian‐dip, asymmetric Fano peak or electromagnetically‐induced‐transparency (EIT)‐like peak can be obtained at a specific resonance wavelength in the whole C‐band. In addition to the different types of line shapes, the extinction ratio can also be enhanced by dynamically tuning the coupling position. This research provides an efficient approach to manipulate the transmission spectra of the Fano resonance, which is of great importance in promoting its further applications on integrated photonics platforms. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of a temperature sensor that utilizes an optical filter consisting of an elliptical-shaped photonic crystal ring resonator (E-PhCRR) in a two-dimensional configuration. The basic structure comprises silicon (Si) rods immersed in the air (disconnected structure) arranged in a triangular lattice. The newly designed structure's photonic band gap (PBG) was calculated using the plane wave expansion (PWE) method, and the temperature sensor was modeled and studied using the finite difference time domain (FDTD). The temperature change causes a redshift in the resonance wavelength due to the subsequent change in refractive index. The temperature was systematically adjusted within the range of 0 °C to 50 °C, leading to a discernible change in the resonant wavelength by 5.2 nm, shifting it from 1682.59 nm to 1687.79 nm. The elliptical shape of the photonic crystal ring resonator provided us with significant flexibility to attain improved outcomes. Specifically, we achieved a quality factor of 316200, a temperature sensitivity of 103.92 pm/°C, and a refractive index sensitivity of 443 nm/RIU. Furthermore, we were able to acquire a detection limit of 5.12 × 10 - 9 RIU while maintaining a compact size of 116.5 μ m 2 . [ABSTRACT FROM AUTHOR]

Whispering gallery mode (WGM) resonators, as an integral component of integrated photonics, have attracted considerable attention due to their high Q factor, small footprint, and small mode volume, making them widely applied as microlasers. In this work, Nd:GGG crystal was prepared into a Nd:GGG film with thickness of 1.8 μm through ion implantation-enhanced etching (IIEE) technique, and subsequently, the Nd:GGG film was partened by focused ion beam (FIB) technology to generate a microdisk with diameter of 20 μm. For high-power microcavity lasers, heat generation during laser operation was inevitable. We placed the microdisk on a silica holder and a silica wafer, respectively. The microdisk placed on the silica holder and silica wafer exhibited laser thresholds of 32 μW and 17 μW, respectively. Moreover, due to different heat dissipation conditions, the microdisk placed on the silica holder exhibited a mode shift of 0.13 nm/mW, while the microdisk placed on the silica wafer showed a more stable laser output state with a mode shift of 0.02626 nm/mW. [ABSTRACT FROM AUTHOR]

We demonstrate the capabilities of a novel frequency-domain terahertz spectrometer based on a comb-locked frequency synthesizer, which provides absolute frequency calibration. The inherent stability and repeatability of the scans allow for the combination of fast data acquisition with an average time-limited signal-to-noise ratio. We demonstrate kilohertz level frequency resolution in terahertz precision spectroscopy of ultra-high quality whispering-gallery-mode resonators. Spectra covering multiple free spectral ranges (>36 GHz) with sub-20 kHz resolution are acquired in 5 s. We analyze the coupling behavior and temperature tuning of single resonances and, for the first time, observe minute red and blue shifts of different mode families. The experimental results are supported with finite element simulations. [ABSTRACT FROM AUTHOR]

Whispering gallery mode (WGM) laser with single‐mode is important for optoelectronic applications because of the higher stability during the light signal transmission. But till now, for InGaN‐based WGM laser, most reports of lasing behavior are multimode lasing. To achieve single‐mode WGM laser, an InGaN‐based micro‐ring laser is proposed and demonstrated with lateral nanoporous distributed Bragg reflector (DBR), where the high‐order lasing modes are strongly suppressed. The side mode suppression ratio (SMSR) is more than 9 times larger than that of the micro‐disk laser with the same radius. Combined with FDTD simulation, the results show that the enhancements are originated from the suppression of the high‐order resonant mode because of the inner boundary of micro‐ring. This work provides a new solution to achieve stable single‐mode WGM laser for future photonic integration. [ABSTRACT FROM AUTHOR]

Here, we demonstrate a strategy that two orthogonal modes in a dielectric cavity can efficiently couple with each other through the bridging effect of a plasmonic antenna. In such a dielectric-antenna hybrid system, a plasmonic antenna can coherently interact with both modes of the dielectric cavity, which brings sufficient coherent energy transfers between the two orthogonal modes. Specifically, a broad electromagnetic mode and a narrow whispering gallery mode (WGM) in a subwavelength silicon disk are considered, where they cannot directly interact with each other through near-field couplings. By introducing a plasmonic antenna, coherent energy transfer between the above two modes occurs, which is confirmed by both far-field spectra and near-field distributions. More investigations show that spectral and spatial overlaps between the involved modes can largely affect energy transfer behaviors. Those overlaps are highly dependent on various parameters of the system. The WGM response in the hybrid system can even exceed that of an individual disk. Our proposed strategy can be extended to other similar systems and the modified optical responses can find applications in enhanced light-matter interactions. [ABSTRACT FROM AUTHOR]

Whispering gallery mode (WGM) optical microcavities have played an essential role in both fundamental research and practical applications, such as cavity quantum electrodynamics, optomechanics, microlasers, and optical sensors. While microcavities made of various materials (e.g., SiO2, As2S3, polymethylmethacrylate) have been extensively investigated, exploiting new materials for microcavities holds great promise for expanding the functionalities of the microcavities. As one of the most ubiquitous and important solids on earth's surface, ice exhibits intriguing optical properties that render it an excellent material for optical applications. Here, ice microsphere optical cavities are demonstrated for the first time. By rapidly freezing water microdroplets, ice microspheres are batch‐fabricated with relatively smooth surfaces and diameters of 5–50 µm. Excitation of a series of WGMs within ice microsphere cavities is achieved over a broad spectral range from near‐ultraviolet to near‐infrared region (380–1600 nm) with quality factors up to 1.4 × 103. Considering the extremely low absorption coefficient of ice in the ultraviolet, this work provides an exceptional platform for exploring ultraviolet microcavity photonics and its diverse applications. [ABSTRACT FROM AUTHOR]

Due to sufficiently high lasing thresholds, stimulated emission in relatively small ZnO microcrystal lasers is often considered to be fed by an inverted electron–hole plasma (EHP). In this study, the nature of optical gain in such emitters is investigated using ZnO microrods 1–6 µm in diameter synthesized by a modified thermal evaporation method and exhibiting whispering-gallery mode (WGM) lasing in the near ultraviolet range. It is demonstrated that optical gain in these objects is not a consequence of population inversion of the EHP at either low or room temperatures. Instead, the primary gain mechanism is the process of scattering of electron–hole pairs by free electrons. Unlike the case of large ZnO WGM microcavities, in small-diameter microrods this process turns out to be dominant over a wide temperature range. [ABSTRACT FROM AUTHOR]

High‐efficient fabrication of well‐ordered nanostructures on flexible substrates is a challenge to surface‐enhanced Raman spectroscopy (SERS) for analytical fingerprinting trace‐detection. In this work, a laser parallel nanofabrication method is reported via incident‐angle‐dependent photonic nanojet ablating Au film on the bottom surface of microsphere‐lens‐array (MLA), for combination with formed dual Au‐nanoholes (MLA/2‐AuNHs) as the flexible SERS substrates. The process parameters, i.e., pulsed laser energy, MLA diameter, Au film thickness, and laser incident angle, are optimized for high finish‐quality of dual‐AuNHs with a diameter of ≈875 nm and a tip gap of ≈90 nm. The SERS substrate demonstrates the limit of detection down to 10−11 M for 4‐nitrobenzenethiol molecules by the multiple optical regulations, including self‐aligned focusing to the hotspots and directional antenna, the strongly localized surface plasmon resonances, and optical whispering‐gallery modes for resonance energy transfer. The flexible PDMS film supporting the rigid MLA holds the SERS performance of MLA/2‐AuNHs with high flexibility. Moreover, the MLA/2‐AuNHs SERS substrate exhibits differential responses to orthogonally polarized excitation, by which the background noises can be eliminated to improve the Raman spectrum. The present work opens new opportunities to fabricate dielectric‐metal flexible SERS substrates by laser parallel nanofabrication via MLA for Raman trace detection. [ABSTRACT FROM AUTHOR]

Laser sensing has a wide range of applications. In this paper, we propose a pH sensing laser with an ultra-low threshold and low sample consumption based on a whispering-gallery-mode microbubble resonator. Rhodamine 6G aqueous solutions with different pH values are injected through microfluidic channels as the lasing gain media and interact with a high-quality factor microbubble cavity with a sample consumption of only 550 pL to achieve lasing. Subtle pH changes of the aqueous solution lead to changes in lasing intensity in real time, and the threshold reaches a minimum of 0.091 μ J/mm2. The low pump energy density effectively avoids the self-aggregation and photobleaching effects of dye molecules present in high-concentration rhodamine 6G solutions. The lasing characteristics under different pH conditions were determined experimentally and theoretically, and the results are in good agreement. Due to the deprotonation of amino groups in highly alkaline environments, the lasing threshold is highly dependent on the pH of rhodamine 6G aqueous solutions. In the pH range of 10.16–13.14, the lasing intensity changes considerably with the increasing pH. The proposed pH-sensing laser exhibits a fast response time, low toxicity, and a high signal-to-noise ratio, making it promising for highly sensitive alkaline detection in biological applications. [ABSTRACT FROM AUTHOR]

The superior stimuli‐responsiveness, narrow linewidth, and high spectral multiplexing capacity of microlasers have led to their use as photonic tags for molecular labeling, encryption, and anticounterfeiting. However, the requirement of consistent lasing features for repeated measurements and the need for lasing features to change regularly with varying analytes pose a challenge to the efficient and convenient authentication of laser‐encoded photonic tags for practical applications. To address this challenge, an optical microsphere array is proposed that provides a set of real‐time typical lasing spectra collected from microspheres coated with specific recognition surface films of different sizes capable of recognizing one analyte or a mixture of analytes. These lasing spectra were transformed into 2D grayscale barcodes. Additionally, a gray value‐quick response code (GV‐QR code) is developed using deep learning methods, which enables the real‐time monitoring and identification of molecular concentration changes through GV‐QR autocoding, resulting in more precise, wide‐ranging, and reliable molecular detection. [ABSTRACT FROM AUTHOR]

Whispering gallery mode resonator sensors are nondisruptive optical sensors that can detect and monitor perturbations in a gaseous environment. Through its resonant properties of peak wavelength, amplitude, and quality factor (Q factor), changes in concentration can be quantified within seconds and monitored over days with great stability. In addition, the small footprint, low cost, and high sensitivity are ideal properties for a disposable sensor that can be utilized in extreme environments. The large Q factor of the resonant cavity enables long interaction lengths and amplifies the effect of small changes in the background refractive index, which is detectable in picometer shifts of the resonance wavelength. However, this measurement is susceptible to changes in other environmental factors such as temperature, pressure, and humidity, which manifest on the picometer wavelength scale, reinforcing the need to decouple the variables. In this work, we compare the spectral response of different diameter resonators to carbon dioxide, nitrogen, and its mixtures, observing the spectral shifting and broadening of the cavity resonance near 1550 nm. In addition, the effect of environmental temperature on spectral shifting due to the thermo-optic effect is characterized and quantified. Lastly, the gas concentrations are changed in real time to showcase the tracking and recovery capabilities of the resonator sensor. [ABSTRACT FROM AUTHOR]

Microring resonators, due to their ability to enable robust strong light–matter interactions within their structures, have garnered substantial interest for their utility in sensing applications, particularly in the realm of gas detection. However, there is an inherent trade-off between a microring resonator's quality factor and confinement factor in the air, making it difficult to balance them. Here, we demonstrate a novel solution with a suspended nanomembrane silicon (SNS) microring resonator. This resonator has ultrathin sub-wavelength thicknesses (0.02–0.03λ), which breaks the trade-off, offering not only a high intrinsic quality factor of 6 × 105 but also an extraordinarily large confinement factor of ∼80% in the air at mid-infrared wavelengths. As a proof-of-concept demonstration, we applied the SNS microring resonator for CO2 gas sensing, exhibiting a sensitivity over 10 times higher than conventional silicon resonators and a large dynamic sensing range spanning from 0% to 100% with a high resolution of better than 4% and chemical specificity. By virtue of its excellent properties, the SNS microring resonator has the potential to open new possibilities for the development of unprecedented nanophotonic integrated circuits, with a broad range of applications in on-chip sensing scenarios. [ABSTRACT FROM AUTHOR]

In this article, the design and simulation of an optical gyroscope based on a hybrid ring resonator using the Sagnac effect are presented. In this design, by using a transfer matrix, numerical analysis, and tight-binding methods, as well as managing control factors in the sensor, such as the transfer coefficient, ring radius of each resonator, operating wavelength, and coupling coefficient, the sensor output parameters are investigated. The output parameters include sensitivity, angular random walk (ARW), minimum angular rotation, minimum group velocity, and the phase shift resulting from the power ratio changes. In this gyroscope, the maximum group velocity in terms of angular rotation with the increase of the number of rings is an exponential function in the range of 750–2500 m/s. The output phase changes as a linear function with an upward slope as the radius of the rigs increases in the range of 2130–3430 nm. Also, with the increase in the radius of the rings, the phase change relative to the operating wavelength decreases. By increasing the imaginary part of the coupling and transfer coefficients in this sensor, the changes in output power decrease compared to the output phase. The transmission peaks in the gyroscope output increase due to the rise in the number of rings. The sensitivity lowers with an increasing number of rings. The temperature affects the gyroscope output, and an increase in temperature causes a rise in ARW and a decrease in the signal-to-noise ratio. Also, the signal-to-noise ratio increases with the rise of the output power due to the transfer and coupling coefficients. [ABSTRACT FROM AUTHOR]

Whispering gallery mode (WGM) resonators have high-quality factors and can be used in high-sensitivity sensors due to the narrow line width that allows for the detection of small external changes. In this paper, a force-sensing system based on a high-Q asymmetric V-shaped CaF2 resonator is proposed. Based on the dispersion coupling mechanism, the deformation of the resonator is achieved by loading force, and the resonant frequency is changed to determine the measurement. By adjusting the structural parameters of the asymmetric V-shaped resonator, the deformation of the resonator under force loading is improved. The experimental results show that the sensitivity of the V-shaped tip is 18.84 V/N, which determines the force-sensing resolution of 8.49 μN. This work provides a solution for force-sensing measurements based on a WGM resonator. [ABSTRACT FROM AUTHOR]

With the aid of 3D full‐field finite difference time–domain simulations, model configurations for CsPbI3 thin‐film solar cell devices that include periodically arranged TiO2 microspheres, exhibiting resonating whispering gallery modes (WGMs), are proposed. The TiO2 microspheres present, either immersed in perovskite or coated with perovskite layer, between the electron‐ and hole‐transport layers show enhanced current‐conversion efficiency. The presence of WGMs lead to enhancement in the absorption of CsPbI3 layer. The incoming electromagnetic wave couples with TiO2 microsphere and forms confined resonating modes. Different designs are examined for deciding the appropriate position of WGM exhibiting spheres with respect to thin‐film perovskite solar cell (PSC) featuring back reflector and optimized antireflectance coating. Since the incoupling element is lossless, energy stored in microspheres is absorbed efficiently by the underlying active material. This directly contributes to the increment in the current density of the solar cell. Thus, the devices show a higher current density of 23.62 mA cm−1, while that in planar solar cell device shows current density of 13.68 mA cm−1, for the same thickness of perovskite layer. This leads to more than 70% enhancement in the short‐circuit current density than the conventional PSCs device of similar size.

In this work, we investigated both spontaneous and stimulated whispering gallery mode (WGM) emissions of 2 mol. % Li+-doped ZnO (Li-ZnO) microspheres with different sizes under 325 and 488 nm wavelength laser excitations, respectively. It was found that all the microspheres exhibit stimulated emissions under a visible laser excitation source of 488 nm wavelength after the threshold pumping power. Thereafter, we studied the dependence of threshold pumping power on the size of microresonators to achieve stimulated emissions by individual microspheres. Furthermore, two microspheres (MS2 and MS3) are excited via a 325 nm UV laser, and surprisingly, the WGM peaks of higher intensity are observed in the visible rather than in the UV spectral region. We expected that most of the emissions are achieved via defect states transitions instead of inter-band transitions in the microresonators. It was found that WGMs in each microsphere exhibit a linear spectral shift of 3–5 nm with increasing pumping power of 488 nm excitation laser source. We believe that these proposed microspheres can be utilized effectively as WGM-based visible lasers and sensors. [ABSTRACT FROM AUTHOR]

Surface‐enhanced Raman spectroscopy (SERS) is a powerful optical technique with high sensitivity to identify analytes down to a single molecule by fingerprinting vibrational information. The strong coupling in microcavities for supermodes with promoted quality factors demonstrates the capability to boost the interaction between photons and molecules for nonlinear effects. Here a strong‐coupling cascade microsphere‐cavity (MC) achieving spontaneous Raman enhancement is reported, for the first time. The cascade MC is composed of two size‐mismatched microspheres, both of which support optical whispering‐gallery modes (WGMs) with significantly different free‐space ranges. The strong coupling between the supported WGMs in the microspheres can be achieved when the quasi‐vernier effect of resonant modes occurs, by which the energy splitting is up to 4 meV. The fast energy transfer between the size‐mismatched MCs therefore increases the quality factor up to 2.1 × 103 for the upper supermode branch. The strong‐coupling cascade MC structure provides an extra enhancement channel for the Au‐based SERS substrate, demonstrating an enhancement factor of Raman intensity (EFRI) up to 2.6 × 1010 for the limit of detection (LoD) down to 10−12 M of 4‐aminothiophenol (4‐ATP). The strong‐coupling cascade MC substrates also exhibit the versatility for identification of multiple analytes for high‐performance Raman trace‐detection applications. [ABSTRACT FROM AUTHOR]

Magnetoelastic micro-electromechanical systems (MEMS) are integral elements of sensors, actuators, and other devices utilizing magnetostriction for their functionality. Their sensitivity typically scales with the saturation magnetostriction and inversely with magnetic anisotropy. However, large saturation magnetostriction and small magnetic anisotropy make the magnetoelastic layer highly susceptible to minuscule anisotropic stress. It is inevitably introduced during the release of the mechanical structure during fabrication and severely impairs the device's reproducibility, performance, and yield. To avoid the transfer of residual stress to the magnetic layer, we use a shadow mask deposition technology. It is combined with a free-free magnetoelectric microresonator design to minimize the influence of magnetic inhomogeneity on device performance. Magnetoelectric resonators are experimentally and theoretically analyzed regarding local stress anisotropy, magnetic anisotropy, and the ΔE-effect sensitivity in several resonance modes. The results demonstrate an exceptionally small device-to-device variation of the resonance frequency < 0.2% with large sensitivities comparable with macroscopic ΔE-effect magnetic field sensors. This development marks a promising step towards highly reproducible magnetoelastic devices and the feasibility of large-scale, integrated arrays. [ABSTRACT FROM AUTHOR]

The reflection and transmission characteristics of a system composed of two whispering‐gallery mode (WGM) resonators are explored. Each resonator contains a Zeeman split quantum dot and side‐couples to an optical fiber. The results indicate that the unidirectional reflectionlessness and transmissionlessness can be achieved by adjusting the coupling strength between the resonators and the optical fiber, as well as the transition rate between the counter‐propagating modes within the WGM resonators. Besides, a one‐to‐one correspondence is set up between the resonance frequencies of quantum dots' energy levels and the positions of reflectionlessness (transmissionlessness) peaks when phase shift between two WGM resonators is π$\pi$. This research provides the valuable insights for the development of quantum optical devices such as isolators, circulators, and routers. [ABSTRACT FROM AUTHOR]

In this work, laterally excited bulk acoustic wave resonators (XBARs) are designed for high-frequency applications in the 5 GHz range which have applications in MEMS sensors and fifth-generation (5G) mobile networks. XBARs are simulated with 400 nm thick LiNbO3 and narrow fingers of Interdigital transducer (IDT) placed periodically with a pitch of 26 µm to excite the lamb wave resonances at 4.49 GHz with a high electromechanical coupling coefficient (kt2) of 32%. The working of XBARs is investigated by Finite element method (FEM) based COMSOL Multiphysics simulation and analytical model. The XBAR schematic is depicted graphically, together with its deformation, impedance response with corresponding asymmetric displacement modes, and device equivalent MBVD model. The performance of XBARs with different piezoelectric materials was investigated, and it was discovered that XBARs using LiNbO3 as piezoelectric materials and Au electrodes performed best. Following that, Au electrodes are used to create A1 (anti-symmetric lamb) modes with spurious mode mitigation. Furthermore, numerous geometrical aspects such as piezoelectric material thickness, IDT finger width, the pitch of IDT and the ratio of IDT finger width to finger gap were examined in order to enhance kt2 and the Quality factor (Q) of the device. The third and fifth harmonics of XBAR were found at 13.41 and 22.39 GHz, respectively. The modified Butterwort-Van Dyke model (MBVD) is intended to discover the XBAR equivalent circuit model. [ABSTRACT FROM AUTHOR]

Single particle analysis is essential for a better understanding of the particle transformation process and to predict its environmental impact. In this study, we developed an aerosol optical tweezer (AOT) Raman spectroscopy system to investigate the phase state and morphology of suspended aerosol droplets in real time. The system comprises four modules: optical trapping, reaction, illumination and imaging, and detection. The optical trapping module utilizes a 532 nm laser and a 100 × oil immersion objective to stably trap aerosol droplets within 30 s. The reaction module allows us to adjust relative humidity (RH) and introduce reaction gases into the droplet levitation chamber, facilitating experiments to study liquid–liquid phase transitions. The illumination and imaging module employs a high-speed camera to monitor the trapped droplets, while the detector module records Raman scattering light. We trapped sodium chloride (NaCl) and 3-methyl glutaric acid (3-MGA) mixed droplets to examine RH-dependent morphology changes. Liquid–liquid phase separation (LLPS) occurred when RH was decreased. Additionally, we introduced ozone and limonene/pinene to generate secondary organic aerosol (SOA) particles in situ, which collided with the trapped droplet and dissolved in it. To determine the trapped droplet's characteristics, we utilized an open-source program based on Mie theory to retrieve diameter and refractive index from the observed whispering gallery modes (WGMs) in Raman spectra. It is found that mixed droplets formed core–shell morphology when RH was decreased, and the RH dependence of the droplets' phase transitions generated by different SOA precursors varied. Our AOT system serves as an essential experimental platform for in situ assessment of morphology and phase state during dynamic atmospheric processes. [ABSTRACT FROM AUTHOR]

Whispering gallery mode (WGM) resonators doped with fluorescent materials find impressive applications in biological sensing. They do not require special conditions for the excitation of WGM inside that provide the basis for in vivo sensing. Currently, the problem of materials for in vivo WGM sensors are substantial since their fluorescence should have stable optical properties as well as they should be biocompatible. To address this we present WGM microresonators of 5–7 μ m, where the dopant is made of carbon quantum dots (CDs). CDs are biocompatible since they are produced from carbon and demonstrate bright optical emission, which shows different bands depending on the excitation wavelength. The WGM sensors developed here were tested as label-free biosensors by detecting bovine serum albumin molecules. The results showed WGM frequency shifting, with the limit of detection down to 10 − 16 M level. [ABSTRACT FROM AUTHOR]

Luminescent supraparticles of colloidal semiconductor nanocrystals can act as microscopic lasers and are hugely attractive for biosensing, imaging, and drug delivery. However, biointerfacing these to increase functionality while retaining their main optical properties remains an unresolved challenge. Here, we propose and demonstrate red-emitting, silica-coated CdSxSe1−x/ZnS colloidal quantum dot supraparticles functionalized with a biotinylated photocleavable ligand. The success of each step of the synthesis is confirmed by scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy, ζ-potential, and optical pumping measurements. The capture and release functionality of the supraparticle system is proven by binding to a neutravidin functionalized glass slide and subsequently cleaving off after UV-A irradiation. The biotinylated supraparticles still function as microlasers; e.g., a 9 μm diameter supraparticle has oscillating modes around 625 nm at a threshold of 58 mJ/cm2. This work is a first step toward using supraparticle lasers as enhanced labels for bionano applications. [ABSTRACT FROM AUTHOR]