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Mid‐infrared soliton lasers leveraging the Raman self‐pumping induced soliton self‐frequency shift (SSFS) effect offer continuously tunable, highly efficient, femtosecond coherent sources that are essential for applications such as spectroscopy, metrology, and quantum optics. However, despite significant advancements in fluoride and chalcogenide fiber platforms, realizing mid‐infrared Raman soliton lasers on on‐chip platforms remains challenging. In this study, the first experimental demonstration of a mid‐infrared Raman soliton laser in an on‐chip Ge28Sb12Se60 (GeSbSe) chalcogenide glass waveguide is presented. A fully fiberized femtosecond fiber laser, centered at 1.96 µm and emitting 246 fs pulses at a 50 MHz repetition rate, is utilized as the pump source, establishing a fiber‐to‐chip configuration. The waveguides are meticulously fabricated using e‐beam lithography and plasma etching, achieving high optical quality and precision in the mid‐infrared regime. Through precise geometrical dispersion engineering, a Raman soliton laser is achieved that continuously tunes from 1960 to 2145 nm within a 32.5 mm long snakelike GeSbSe strip waveguide. The threshold for pump peak power is remarkably low, at just 14.1 W (3.47 pJ). Additionally, a more than one‐octave‐spanning near to mid‐infrared supercontinuum (1320–2760 nm at 22.9 pJ), reinforced by the combined Kerr and Raman effects, is also realized, confirming the versatile performance of the proposed GeSbSe waveguide. These findings pave the way for mid‐infrared on‐chip Raman soliton lasers, highlighting their potential for power‐efficient, low‐cost, and field‐deployable on‐chip applications in the mid‐infrared regime. [ABSTRACT FROM AUTHOR]

Abstract Along with the constantly evolving functional microsystems toward more diversification, the more rigorous design deliberation of pursuing higher mass‐loading of electrode materials and low‐temperature fabrication compatibility have imposed unprecedented demand on integrable all‐solid‐state thin‐film microbatteries. While the classic thin‐film intercalation cathode prepared by vacuum‐based techniques inevitably encountered a post‐annealing process, tape‐casting technologies hold great merits both in terms of high‐mass loading and low‐temperature processing. In this work, a novel microbattery configuration is developed by the combination of traditional tape‐casting thick electrodes and sputtered inorganic thin‐film solid electrolytes (~3 μm lithium phosphorus oxynitride). Enabled by physically pressed or vapor‐deposited Li as an anode, solid‐state batteries with tape‐casted LiFePO4 electrodes exhibit outstanding cyclability and stability. To meet integration requirements, LiFePO4/LiPON/Si microbatteries were successfully fabricated at low temperatures and found to achieve a wide operating temperature range. This novel configuration has good prospects in promoting the thin‐film microbattery enabling a paradigm shift and satisfying diversified requirements.

Integrated photonic devices are essential for on-chip optical communication, optical-electronic systems, and quantum information sciences. To develop a high-fidelity interface between photonics in various frequency domains without disturbing their quantum properties, nonlinear frequency conversion, typically steered with the quadratic (χ2) process, should be considered. Furthermore, another degree of freedom in steering the spatial modes during the χ2 process, with unprecedent mode intensity is proposed here by modulating the lithium niobate (LN) waveguide-based inter-mode quasi-phase-matching conditions with both temperature and wavelength parameters. Under high incident light intensities (25 and 27.8 dBm for the pump and the signal lights, respectively), mode conversion at the sum-frequency wavelength with sufficient high output power (−7 – 8 dBm) among the TM01, TM10, and TM00 modes is realized automatically with characterized broad temperature (ΔT ≥ 8 °C) and wavelength windows (Δλ ≥ 1 nm), avoiding the previous efforts in carefully preparing the signal or pump modes. The results prove that high-intensity spatial modes can be prepared at arbitrary transparent wavelength of the χ2 media toward on-chip integration, which facilitates the development of chip-based communication and quantum information systems because spatial correlations can be applied to generate hyperentangled states and provide additional robustness in quantum error correction with the extended Hilbert space.

Micro energy sources as the nucleus of intelligent microdevices guarantee their full autonomy in the dimensions of time and space. However, the state‐of‐the‐art micro energy storage components, like all‐solid‐state thin‐film microbatteries (ASSTFBs), whose direct integration is impeded by the stereotyped vacuum‐based manufacturing technologies, for which an inevitable high‐temperature annealing step (> 500 °C) can exert catastrophic effects on the attached microdevices during the crystallization of manufactured insertion thin‐film cathodes, especially in flexible integration. Herein, a prototype construction is created to benchmark concrete feasibility for the low‐temperature manufacturing of ASSTFBs via a nonvacuum‐based spin‐coating electrode architecture. Results show that the spin‐coated LiFePO4 films enable low‐temperature (≈ 45 °C) manufacturing of ASSTFBs, by which it can deliver excellent cycling performance up to 1000 cycles. Importantly, this technology presents the versatility of integrating various cathode composites into ASSTFBs and is therefore generalized to the LiCoO2‐ and Li4Ti5O12‐based solid‐state chemistries. Furthermore, ASSTFBs with such compliant electrodes manifest outstanding flexibility without pronounced capacity degradation by successfully integrating on flexible temperature‐sensitive substrates. The spin‐coating protocol provides a general solution for excessive processing temperatures and ample opportunities for the development of on‐chip integratable and flexible ASSTFBs. [ABSTRACT FROM AUTHOR]

Optical phased array (OPA), as a promising beam steering technology, however, usually suffers from a narrow field of view (FOV) that limits its performances in applications. A miniaturized compact strategy to enlarge the beam steering angle is quite desirable for the solid-state OPA technique. Here an on-chip metasurface-doublet is proposed to offer angle magnification integrated with a port-selected optical phased array. It is implemented by combing convex and concave metalenses with the quadratic phase distribution, which is precisely integrated on the OPA chip by layer-by-layer fabrication process. Here, the OPA is fabricated in Lithium Niobate on Insulator (LNOI) platform. Our experiments show that the metasurface-doublet is able to achieve 1.54 times FOV amplification in a horizontal direction and with >41% working efficiency. Our results provide a feasible approach to achieve enlarged FOV for wide-angle beam steering and also imply a powerful platform in developing integrated multilayer metasurface devices.

GaN-based microring lasers grown on Si are promising candidates for compact and efficient light sources in Si-based optoelectronic integration and optical interconnect due to their small footprints, low mode volume, low power consumption, and high modulation rate. However, the high symmetry of circular microcavity leads to isotropic emission, which not only reduces the light collection efficiency, but also affects other adjacent devices during data transmission. In this study, the unidirectional lasing emission of room-temperature current-injected GaN-based microring laser was realized by coating metal Ag on the microring sidewall and integrating a direct coupled waveguide. The light was efficaciously confined in the cavity and only emitted from the waveguide, which avoided optical signal crosstalk with other adjacent devices. Furthermore, we integrated a microdisk at the other end of the waveguide as a photodetector, which could effectively detect the output power of the microring laser from the direct coupled waveguide. Therefore, a preliminary on-chip integration of GaN-based microring laser, waveguide and photodetector on Si substrate was successfully demonstrated for the first time, opening up a new way for on-chip integration and optical interconnect on a GaN-on-Si platform.

We report highly selective resonant emission from an aperiodic Tamm plasmon-polariton (TP) emitter featuring a targeted mid infrared emission wavelength in the region of 4.26 μm. This spectral region is of high interest in context with integrated CO2 absorption sensing. To the best of our knowledge, the measured thermal emission at peak temperatures up to 500 °C of TP emitters featuring a half-wavelength cavity have never been related to simulations in a satisfactory manner in terms of peak position, emission intensity and temperature behavior. The layer thicknesses quantified via scanning electron microscope (SEM) featured deviations from the targeted periodic configuration due to statistical variation of deposition and etching process. Simulations using the Transfer-Matrix Method suggested a higher Q-factor and higher peak emission associated with the obtained aperiodic configurations compared to the target periodic configuration featuring a quarter-wave stack (QWS). Although the improved spectral features of the aperiodic stack could not quite be resolved, the spectral position, the qualitative temperature behavior and the angular emission pattern in the range of 0° to 10° could be confirmed by Fourier-transform infrared (FTIR) spectroscopy.

On-chip arbitrary-elliptical-polarization converter plays a key role in optical information processing. However, the traditional method of manually adjusting parameters for designing devices is limited in function. In this letter, on-chip ultra-small arbitrary-elliptical-polarization converters are realized through optimization algorithms based on genetic algorithm (GA) combined with finite element method (FEM). The converters can realize the function of arbitrary ellipticity angle conversion of full polarization states. The size of the core device is only 1 µm × 1 µm, which is very conducive to high-density integration. The difference between the ideal output ellipticity angle and the actual output ellipticity angle of each device is no more than 2 degrees. In addition, it is proved that the use of optimization algorithms can easily design arbitrary-elliptical-polarization converters with different materials, different structures and different wavelengths, and the design of three-dimensional arbitrary-elliptical-polarization converters is also verified by using the optimization algorithm. This work provides an efficient design method for arbitrary polarization state conversion, showing its significance in improving the information capacity in optical communication.

Cascaded nanophotonic devices play a vital role in all-optical connection, all-optical computation and all-optical network. However, there is almost no effective method for the direct design of on-chip cascaded nanophotonic devices, since current study of nanophotonic devices mostly focuses on single device. Here, on-chip cascaded nanophotonic devices are designed based on an intelligent algorithm by combining genetic algorithm, simulated annealing algorithm and finite element method for the first time, and verified experimentally by using silicon-based planar structures. The cascaded devices consist of a bandpass filter and a wavelength router operating in optical communication range. The operation bandwidth of the bandpass filter is 408 nm with transmission more than 80%, within which the communication wavelengths of 1,300 nm and 1,550 nm are routed into different output ports through the wavelength router component. The footprint is only 3.62 μm2 for the bandpass filter and only 2.56 μm2 for the wavelength router, which are easy for integration with planar structures and ultrasmall size. This work provides a highly-efficient scheme for the realization of on-chip cascaded nanophotonic devices on the same chip, and lays a foundation for the realization of photonic chip based on intelligent algorithm.

The orthogonality among optical beams with different orbital angular momentum (OAM) modes presents a new perspective as independent data‐carrying channels for multiplexing and demultiplexing. In particular, the theoretically infinite topological charge of OAM beam promises the unbounded capacity in communication systems. As a key part for the advancement of OAM technologies, OAM source has attracted considerable interest and experienced a rapid development. Nevertheless, conventional approaches to create OAM modes mainly rely on the use of bulky optical devices and external laser source, preventing their implementation into a miniaturized system. As a contrast, on‐chip generation of OAM beams with a built‐in source stands out with several advantages, including small footprint, compactness, portability, and high‐power efficiency. In this work, a versatile approach to directly produce OAM modes with on‐demand characteristics on a chip is demonstrated. Featuring the judicious combination of the emerging dielectric metasurface with the standard vertical cavity surface‐emitting laser (VCSEL) platform, the approach represents a feasible solution to the wide implementation of wafer‐level OAM emitters for optoelectronic integrations. Prototype laser chips for the generation of both individual OAM beam and OAM array with novel functionalites, such as controllable directionality and spatially varying topological charge and distribution, are systematically presented. [ABSTRACT FROM AUTHOR]

Vast applications of mid-infrared await the realisation of integrated photonic systems for this unique spectrum. Despite its potential as a universal platform for diverse active functions in mid-infrared, black phosphorus (BP) photonics still lacks integrated modulators for completion. Here we realize a hybrid integration of mid-infrared BP modulator on silicon photonics waveguide. Through gating effect, the anisotropic absorption in armchair BP can be tuned for enabling efficient optical modulation spanning ∼3.85–4.1 μm. The integrated waveguide design further promotes light–BP interaction that achieves a modulation depth of ∼5 dB at a low bias of −4 V. Additionally, the active footprint of 225 μm2 and the switching energy of ∼2.6 pJ are remarkably smaller compared to traditional counterparts. Function diversity of such a platform is further verified by integrating BP photodetector and modulator. The combination of two-dimensional materials and silicon photonics manifests a versatile platform to realise high-performance optoelectronic devices for compact on-chip mid-infrared system.

On-chip arbitrary-elliptical-polarization converter plays a key role in optical information processing. However, the traditional method of manually adjusting parameters for designing devices is limited in function. In this letter, on-chip ultra-small arbitrary-elliptical-polarization converters are realized through optimization algorithms based on genetic algorithm (GA) combined with finite element method (FEM). The converters can realize the function of arbitrary ellipticity angle conversion of full polarization states. The size of the core device is only 1 µm × 1 µm, which is very conducive to high-density integration. The difference between the ideal output ellipticity angle and the actual output ellipticity angle of each device is no more than 2 degrees. In addition, it is proved that the use of optimization algorithms can easily design arbitrary-elliptical-polarization converters with different materials, different structures and different wavelengths, and the design of three-dimensional arbitrary-elliptical-polarization converters is also verified by using the optimization algorithm. This work provides an efficient design method for arbitrary polarization state conversion, showing its significance in improving the information capacity in optical communication. [ABSTRACT FROM AUTHOR]

The fabrication of GaN light-emitting diodes (LEDs) with on-chip photodetectors (PDs) based on flip-chip configuration is reported. The exposed sapphire plays a key role not only in light extraction but also light guiding in the lateral direction. The same InGaN/GaN quantum well structure responsible for light emission in the LED and photodetection in the PD is characterized. The light-detecting mechanism of on-chip PDs at varying positions are also studied and verified by simulation. Compared with the design of PD adjacent to the LED, the PD formed in the center of the LED has less influence on the uniformity of the LED emission, and exhibits one-third increase in photocurrent. The flip-chip packaging device also enables a yellow phosphor film to be directly integrated onto the sapphire surface to generate white light emission. The on-chip PD is capable of detecting the variation of LED intensity without blocking the light output emission, which makes it highly valuable for real-time detection of the intensity of LED sources in various lighting applications. [ABSTRACT FROM AUTHOR]

Quantum emitters serve as the building blocks of quantum network, connecting quantum computing, quantum communication and quantum metrology. Semiconductor quantum dots ( QDs) are widely considered as the best candidate for quantum emitters. By a decade of effort, the controllability, purity, brightness, indistinguishability, and coherence of QD emitters are greatly improved so that they are much closer to the application level. In this paper, the scientific and technological development of quantum emitters based on QDs were reviewed. Firstly, QD-based single photon sources have achieved indistinguishability of near unity, high purity, and high extraction efficiency. Secondly, QD-based entangled photon emitters have achieved high bit rate, high entanglement fidelity by improvements such as eliminating fine structure splitting. Thirdly, remarkable development has been made towards on-chip integration of QD emitters into planar circuits and nano-photonic systems. It turns out that quantum emitters based on semiconductor QDs are greatly potential to be applied in quantum information processing systems in the near future. [ABSTRACT FROM AUTHOR]

Nanophotonic polarization routers, which can separate and steer light with different polarizations of transverse electric and transverse magnetic modes into different output ports, are an essential component of on‐chip integrated photonic circuits. By developing an intelligent algorithm that combines the genetic algorithm and the finite element method, various polarization routers possessing different operation bands, different structures, and different materials, which can be easily fabricated and integrated, are successfully designed. On‐chip ultrasmall silicon‐based polarization routers are experimentally demonstrated in the near‐infrared range. The footprint is only 970 nm × 1240 nm, which is the smallest demonstrated. The measured normalized transmission is up to 85% in the near infrared range. Additionally, a broadband highly efficient photon coupler is also achieved based on disordered‐grating configurations designed by the intelligent algorithm. This breaks the restrictions of traditional structures, provides a universal platform for the realization of nanophotonic polarization routers, and paves a way for the design and high‐density on‐chip integration of nanophotonic devices. [ABSTRACT FROM AUTHOR]

Autonomous sensor systems and networks are of increasing demand toward the realization of the Internet of Things (IoT). In this respect, integrated devices for energy storage and management, such as microcapacitors and microbatteries, are intensively studied. Their integration with Si electronics is highly desirable, as it offers important advantages related to fabrication simplicity and cost reduction. Moreover, microcapacitors as compared with microbatteries offer additional advantages, including a theoretically infinite number of charge/discharge cycles, which makes them more appropriate for truly autonomous systems. They thus constitute the focus herein. Their basic characteristics for use in energy storage are discussed, and their interdependence is demonstrated, along with the demonstration that those characteristics cannot be independently optimized for energy storage. The two types of existing microcapacitors, namely the solid‐state microcapacitors and the microsupercapacitors, are presented in terms of their fabrication and integration schemes and their energy‐storage characteristics. Their advantages and disadvantages for the specific applications are analyzed. The usefulness of solid‐state microcapacitors in the above application, despite their significantly lower capacitance density compared with microsupercapacitors, is demonstrated, attributed to their integration maturity with standard complimentary metal‐oxide‐semiconductor (CMOS) processing, in addition to their larger charging voltages and maximum frequencies of operation. [ABSTRACT FROM AUTHOR]

The topological nanophotonic wavelength router, which can steer light with different wavelength signals into different topological channels, plays a key role in optical information processing. However, no effective method has been found to realize such a topological nanophotonic device. Here, an on-chip topological nanophotonic wavelength router working in an optical telecom band is designed based on a topology optimization algorithm and experimentally demonstrated. Valley photonic crystal is used to provide a topological state in the optical telecom band. The measured topological wavelength router has narrow signal peaks and is easy for integration. This work offers an efficient scheme for the realization of topological devices and lays a foundation for the future application of topological photonics.

Surface plasmon polaritons (SPPs) have been attracting considerable attention owing to their unique capabilities of manipulating light. However, the intractable dispersion and high loss are two major obstacles for attaining high-performance plasmonic devices. Here, a graphene nanoribbon gap waveguide (GNRGW) is proposed for guiding dispersionless gap SPPs (GSPPs) with deep-subwavelength confinement and low loss. An analytical model is developed to analyze the GSPPs, in which a reflection phase shift is employed to successfully deal with the influence caused by the boundaries of the graphene nanoribbon (GNR). It is demonstrated that a pulse with a 4 μm bandwidth and a 10 nm mode width can propagate in the linear passive system without waveform distortion, which is very robust against the shape change of the GNR. The decrease in the pulse amplitude is only 10% for a propagation distance of 1 μm. Furthermore, an array consisting of several GNRGWs is employed as a multichannel optical switch. When the separation is larger than 40 nm, each channel can be controlled independently by tuning the chemical potential of the corresponding GNR. The proposed GNRGW may raise great interest in studying dispersionless and low-loss nanophotonic devices, with potential applications in the distortionless transmission of nanoscale signals, electro-optic nanocircuits, and high-density on-chip communications.

The study critically reviews the silicon‐based microphotonic biosensors for biomedical applications. In particular, integrated optical devices and their advantages, in terms of high performance and compactness, and also high reliability and long life term, are reported. These features, together with the complementary metal oxide semiconductor compatibility of the silicon technology, since the last few years, have been allowing to realise high‐efficiency biosensing platforms with on‐chip integration of several biosensors for a multi‐analyte detection. Many lab‐on‐chip systems integrated into portable medical instruments have been proposed in the literature and some of them already commercialised in the worldwide market, so attaining extraordinary improvements in the early detection and monitoring of several diseases. Therefore, fast and accurate self‐tests achievable with silicon photonic biosensors are remarkably opening new possibilities and applications in the healthcare industry. [ABSTRACT FROM AUTHOR]

A novel on-chip integration of pressure plus 2-axis (X/Z) acceleration composite sensors for upgraded production of automobile tire pressure monitoring system (TPMS) is proposed, developed, and characterized. Herein, the X-axis accelerometer is with the cantilever beam-mass structure and is used for automatically identifying and positioning each of the four wheels. The IC-Foundry-Compatible low-cost batch fabrication technique of MIS (i.e., Micro-openings Inter-etch and Sealing) is employed to only fabricate the device from the front side of (111) silicon wafer, without double-sided micromachining, wafer bonding, complex Cavity-SOI (Silicon on Insulator) processing, and expensive SOI-wafer needed. Benefited from the single-wafer front-side fabrication technique on ordinary single-polished wafers, the fabricated composite TPMS sensor has the advantages of a small chip-size of 1.9 mm × 1.9 mm, low cross-talk interference, low-cost, and compatible process with IC-foundries. The fabricated pressure sensors, X-axis accelerometer and Z-axis accelerometer, show linear sensing outputs, with the sensitivities as about 0.102 mV/kPa, 0.132 mV/kPa, and 0.136 mV/kPa, respectively. Fabricated with the low-cost front-side MIS process, the fabricated composite TPMS sensors are promising in automotive electronics and volume production.

One important building block for future integrated nanophotonic devices is the scalable on-chip interfacing of single photon emitters and quantum memories with single optical modes. Here we present the deterministic integration of a single solid-state qubit, the nitrogen-vacancy (NV) center, with a photonic platform consisting exclusively of SiO _2 grown thermally on a Si substrate. The platform stands out by its ultra-low fluorescence and the ability to produce various passive structures such as high-Q microresonators and mode-size converters. By numerical analysis an optimal structure for the efficient coupling of a dipole emitter to the guided mode could be determined. Experimentally, the integration of a preselected NV emitter was performed with an atomic force microscope and the on-chip excitation of the quantum emitter as well as the coupling of single photons to the guided mode of the integrated structure could be demonstrated. Our approach shows the potential of this platform as a robust nanoscale interface of on-chip photonic structures with solid-state qubits.

Femtosecond laser micromachining has been a promising technique for fabricating three-dimensional (3D) micro/nano-structures in various kinds of dielectric materials with unprecedented spatial resolutions as well as flexibility in terms of the geometry and the materials can be processed. This unique capability opens opportunities for fabrication of 3D high-quality (Q) microresonators, which are one of the key elements in modern photonic applications. Here, we review the recent progress in fabrication of high-Q microresonators on glass and crystalline substrates by employing femtosecond laser direct writing. We demonstrate the applications of the fabricated microresonators in generating low-threshold lasers, high-sensitivity chemical sensing and nonlinear optical wavelength conversion. [ABSTRACT FROM AUTHOR]

Next-generation mid-infrared (MIR) imaging chips demand free-cooling capability and high-level integration. The rising two-dimensional (2D) semimetals with excellent infrared (IR) photoresponses are compliant with these requirements. However, challenges remain in scalable growth and substrate-dependence for on-chip integration. Here, we demonstrate the inch-level 2D palladium ditelluride (PdTe 2 ) Dirac semimetal using a low-temperature self-stitched epitaxy (SSE) approach. The low formation energy between two precursors facilitates low-temperature multiple-point nucleation (∼300 °C), growing up, and merging, resulting in self-stitching of PdTe 2 domains into a continuous film, which is highly compatible with back-end-of-line (BEOL) technology. The uncooled on-chip PdTe 2 /Si Schottky junction-based photodetector exhibits an ultrabroadband photoresponse of up to 10.6 μm with a large specific detectivity. Furthermore, the highly integrated device array demonstrates high-resolution room-temperature imaging capability, and the device can serve as an optical data receiver for IR optical communication. This study paves the way toward low-temperature growth of 2D semimetals for uncooled MIR sensing.

An integrated way to generate and manipulate higher-order Poincaré sphere beams (HOPBs) is a sought-after goal in photonic integrated circuits for high-capacity communication systems. Here, we demonstrate a novel method for on-chip generation and manipulation of HOPBs through combining metasurface with optical waveguides on lithium niobate on insulator platform. With phase modulation by a diatomic geometric metasurface, guided waves are extracted into free space with a high signal-to-noise ratio in the form of two orthogonal circularly polarized optical vortices which are linearly superposed into HOPBs. Meanwhile, a dual-port waveguide crossing is established to reconfigure the output states into an arbitrary point on a higher-order Poincaré sphere based on in-plane interference of two guided waves. Our approach provides a promising solution to generate and manipulate the HOPBs in a compact manner, which would be further enhanced by employing the electro-optical modulation on a lithium niobate waveguide to access a fully tunable scheme.

We developed a fabrication method for colloidal photonic crystal films and arrays with high quality and uniform thickness without need for any lithography. The method, “directed enhanced evaporation for colloidal assembly” (DEECA), employs a two-step process: a capillarity-induced infilling of an aqueous dispersion of colloidal particles within the thin two-dimensional (2D) channel arrays, followed by enhanced evaporation of water through the inlet, leading to laminar flow of the colloidal dispersion and subsequent colloidal crystallization. DEECA was confirmed to be a fast, precise and a cost-effective process with minimum loss of colloidal particles for preparing multiple opalline scaffold structures toward on-chip integrated photonic bandgap device arrays. To prove this, 2D arrays of poly(hydroxyethylmethacrylate) (PHEMA)-based inverse opal (IO) photonic gel pH sensors were fabricated via templated-photopolymerization of the precursor mixtures within the DEECA cells. It was confirmed that on-chip integrated photonic gel pH sensor arrays could be successfully implemented by using opal templates prepared via DEECA. DEECA could also be utilized for opal-templated fabrication of TiO 2 inorganic IO film arrays on a glass substrate. [ABSTRACT FROM AUTHOR]

Today's supercapacitor energy storages are typically discrete devices aimed for printed boards and power applications. The development of autonomous sensor networks and wearable electronics and the miniaturization of mobile devices would benefit substantially from solutions in which the energy storage is integrated with the active device. Nanostructures based on porous silicon (PS) provide a route towards integration due to the very high inherent surface area to volume ratio and compatibility with microelectronics fabrication processes. Unfortunately, pristine PS has limited wettability and poor chemical stability in electrolytes and the high resistance of the PS matrix severely limits the power efficiency. In this work, we demonstrate that excellent wettability and electro-chemical properties in aqueous and organic electrolytes can be obtained by coating the PS matrix with an ultra-thin layer of titanium nitride by atomic layer deposition. Our approach leads to very high specific capacitance (15 F cm −3 ), energy density (1.3 mWh cm −3 ), power density (up to 214 W cm −3 ) and excellent stability (more than 13,000 cycles). Furthermore, we show that the PS–TiN nanomaterial can be integrated inside a silicon chip monolithically by combining MEMS and nanofabrication techniques. This leads to realization of in-chip supercapacitor, i.e., it opens a new way to exploit the otherwise inactive volume of a silicon chip to store energy. [ABSTRACT FROM AUTHOR]

Metasurface polarization optics that consist of 2D array of birefringent nano-antennas have proven remarkable capabilities to generate and manipulate vectorial fields with subwavelength resolution and high efficiency. Integrating this new type of metasurface with the standard vertical cavity surface-emitting laser (VCSEL) platform enables an ultracompact and powerful solution to control both phase and polarization properties of the laser on a chip, which allows to structure a VCSEL into vector beams with on-demand wavefronts. Here, this concept is demonstrated by directly generating versatile vector beams from commercially available VCSELs through on-chip integration of high-index dielectric metasurfaces. Experimentally, the versatility of the approach for the development of vectorial VCSELs are validated by implementing a variety of functionalities, including directional emission of multibeam with specified polarizations, vectorial holographic display, and vector vortex beams generations. Notably, the proposed vectorial VCSELs integrated with a single layer of beam shaping metasurface bypass the requirements of multiple cascaded optical components, and thus have the potential to promote the advancements of ultracompact, lightweight, and scalable vector beams sources, enriching and expanding the applications of VCSELs in optical communications, laser manipulation and processing, information encryption, and quantum optics., (© 2023 Wiley-VCH GmbH.)

For the first time, high-vacuum ion-sorption MEMS micropump has been integrated with other vacuum MEMS devices. The first integrated device consists of a Pirani vacuum gauge and a micropump, the second – consists of a field-emission electron source and a micropump. Tandem device Pirani gauge – micropump forms a single-unit vacuum meter. Tandem device electron source – micropump enables obtaining a more stable electron beam gun after residual gas removal. The preliminary results presented here confirm the possibility of fabricating new high vacuum MEMS instruments with own pumping and vacuum monitoring system on-chip. [ABSTRACT FROM AUTHOR]

Microelectromechanical-system (MEMS)-based semiconductor gas sensors are considered one of the fastest-growing, interdisciplinary high technologies during the post-Moore era. Modern advancements within this arena include wearable electronics, Internet of Things, and artificial brain-inspired intelligence, among other modalities, thus bringing opportunities to drive MEMS-based gas sensors with higher performance, lower costs, and wider applicability. However, the high demand for miniature and micropower sensors with unified processes on a single chip imposes great challenges. This review focuses on recent developments and pitfalls in MEMS-based micro- and nanoscale gas sensors and details future trends. We also cover the background of the topic, seminal efforts, current applications and challenges, and opportunities for next-generation systems.

Erbium-doped optical waveguide amplifier (EDWA) is an important building block for conventional and integrated optical communication and light signal processing systems. In recent years remarkable advancement has been achieved for EDWA to meet the demand for silicon photonic chips and integrated photonic circuits. However, in the currently demonstrated EDWAs all the laser pumping sources are external or off-chip, which not only limits the application field of EDWA, complicates the amplification scheme, but also does not fulfill the expectation of monolithic integration. In this work we propose a design of EDWA using high-gain Er-doped Al 2 O 3 waveguide, low-loss silicon-on-insulator (SOI) waveguide, and on-chip integrated semiconductor laser pumping source. The 1550 nm signal light and 1480 nm pump light are transmitted and combined in SOI waveguide and coupled into the EDWA waveguide embedded in the adjacent layer. The 1480 nm pump light is coupled into the SOI waveguide from a bonded hybrid III–V semiconductor laser. The pump and signal waveguide building scheme, the coupling method and structure, and the integration process of laser pumping source are shown and simulated. The system performance was evaluated by using the device's structure parameters and Er 3 + rate equation model. More than 1 dB/cm net gain and up to 35 dB maximum net gain can be achieved at about 100 mW pump power. It indicates that such an on-chip integration design is feasible and fully on-chip integrated optical waveguide amplifier could be achieved. • An Erbium-doped Al 2 O 3 waveguide amplifier with on-chip integrated III–V/SOI​ hybrid pump laser was proposed and designed. • Double photonic layers used for the SOI waveguide and the EDWA including all the coupling components. • Simulation and rate equation modeling indicate more than 30 dB gain achieved. [ABSTRACT FROM AUTHOR]

Photonic crystal technology has attracted large interest in the last years. The possibility to generate highly sensitive sensor elements with photonic crystal structures is very promising for medical or environmental applications. The low-cost fabrication on the mass scale is as advantageous as the compactness and reliability of photonic crystal biosensors. The possibility to integrate microfluidic channels together with photonic crystal structures allows for highly compact devices. This article reviews different types of photonic crystal sensors including 1D photonic crystal biosensors, biosensors with photonic crystal slabs, photonic crystal waveguide biosensors and biosensors with photonic crystal microcavities. Their applications in biomolecular and pathogen detection are highlighted. The sensitivities and the detection limits of the different biosensors are compared. The focus is on the possibilities to integrate photonic crystal biosensors on-chip. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

This letter presents a smart driver for LEDs, particularly for automotive lighting applications, which avoid ringing and overshoot phenomena. To this aim, advanced Soft Start and Current Slope Control techniques are integrated on-chip. This letter discusses the driver design integrating in high voltage CMOS technology, the digital circuitry for programming and electronic control units interfacing, and the power devices up to 10 W. Experimental characterizations with LEDs of different power levels and with different types of connections are showed. The smart driver sustains automotive temperature and voltage requirements; moreover it has high power efficiency, it is programmable, and can be configured to work as a linear regulator (for low current LEDs) or in switch mode (for higher power LEDs). [ABSTRACT FROM AUTHOR]

Micrometric white light emitters were fabricated by applying two-photon polymerization (TPP) lithography to a chemically modified resist. Such a functional resist (FR) was doped with fluorescent molecules to turn it emitting into the whole visible region. The TPP has shown to be a versatile, low cost maskless technique capable to fabricate highly resolved structures in our FR's. The spectroscopic and chromaticity properties of the FR and fabricated microscale structures were investigated. Structures emitting high quality of white light were obtained and classified into two categories: physical and physiological white light emitters. Finally, a lifetime study was performed with the aim to apply such structures as light sources for on chip integrated photonic devices. [Display omitted] • Optical analysis of photoresist chemically modified by organic fluorophores • Two-photon lithography on chemically modified photoresist • Fabrication and optical analysis of micrometer scale white light emitters • White light emitters for on-chip photonic integration [ABSTRACT FROM AUTHOR]

Abstract: An on-chip-micromachined tunable LC-tank, which consists of a metal inter-digitated variable capacitor and a metal solenoid inductor, is developed for wide-range radio-frequency (RF) tuning in multi-GHz band. A low-temperature metal MEMS process is developed to on-chip fabricate the passives. The process can be used for post-CMOS-compatible integration with RF ICs. Both the varactor and the inductor are suspended with a gap from the low-resistivity silicon wafer (i.e. standard CMOS wafer) for effectively depressing RF loss. The fabricated variable capacitor part, the inductor part and the whole tunable LC resonator are sequentially tested, finally resulting in a wide resonance-frequency tuning range of 72% (between about 3.5 and 6.0GHz) under a low tuning voltage range of 0–4V, while the Q-factor ranged within 23 and 8. [Copyright &y& Elsevier]

We monolithically integrated polycrystalline GaAs metal-semiconductor-metal (MSM) photoconductive switches with a completely fabricated Si-CMOS amplifier and obtained a properly functional optical receiver, without altering the Si circuit performance. To our knowledge, this is the first time a fully monolithic on-chip integration has been achieved. [ABSTRACT FROM PUBLISHER]

Miniature diffraction gratings (μgratings) have been fabricated using focused ion beam (FIB) milling. This FIB "direct write" (maskless/resistless) patterning technique is very well suited for the fabrication of micrometer-scale gratings and for their on-chip integration with other photonic components for fiber-optic communications applications. μgratings in sizes from 20 to 250 μm with groove center-to-center spacing from 200 nm to 2 μm have been fabricated. The diffraction efficiency of the μgratings was investigated as a function of FIB dose. A maximum of 40% efficiency was obtained for nonpolarized 632.8-nm light and 50% for P-polarized light. A technique was developed for the fabrication of μgratings on angled facets and for their integration with optical fibers. The fiber-coupled μgrating was operated as a diffractive optical element (DOE) at 1.5 μm. The diffractive wavelength resolution in these first FIB-fabricated DOEs was measured to be ∼10 nm using a tunable laser in the range 1510-1580 nm. Future such DOEs have the potential to reach the sub-nm resolution level. [ABSTRACT FROM PUBLISHER]

The miniaturization of optical isolators and their on-chip integration with various optoelectronic devices has been pursued for a number of years. However, reducing the standard paradigmatic construction used in commercial isolators to waveguide form requires stringent fabrication tolerances and special materials that tend to render the process difficult and costly. Thus, novel approaches in device design and materials technology are called for and are being pursued. This paper discusses the application of the Faraday and nonreciprocal phase shift effects in waveguide isolator operation, the complications that arise in the miniaturization of these devices, and the novel solutions being pursued. [ABSTRACT FROM PUBLISHER]

The topological nanophotonic wavelength router, which can steer light with different wavelength signals into different topological channels, plays a key role in optical information processing. However, no effective method has been found to realize such a topological nanophotonic device. Here, an on-chip topological nanophotonic wavelength router working in an optical telecom band is designed based on a topology optimization algorithm and experimentally demonstrated. Valley photonic crystal is used to provide a topological state in the optical telecom band. The measured topological wavelength router has narrow signal peaks and is easy for integration. This work offers an efficient scheme for the realization of topological devices and lays a foundation for the future application of topological photonics. [ABSTRACT FROM AUTHOR]

This work presents an ultra-low-power CMOS supercapacitor storage unit suitable for a plethora of low-power autonomous applications. The proposed unit exploits the unregulated voltage output of harvesting circuits (i.e., DC-DC converters) and redirects the power to the storage elements and the working loads. Being able to adapt to the input energy conditions and the connected loads' supply demands offers extended survival to the system with the self-startup operation and voltage regulation. A low-complexity control unit is implemented which is composed of power switches, comparators and logic gates and is able to supervise two supercapacitors, a small and a larger one, as well as a backup battery. Two separate power outputs are offered for external load connection which can be controlled by a separate unit (e.g., microcontroller). Furthermore, user-controlled parameters such as charging and discharging supercapacitor voltage thresholds, provide increased versatility to the system. The storage unit was designed and fabricated in a 0.18 um standard CMOS process and operates with ultra-low current consumption of 432 nA at 2.3 V. The experimental results validate the proper operation of the overall structure. [ABSTRACT FROM AUTHOR]