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Despite rather extensive study of the random lasing effect in ZnO structures, the issue of the optical gain mechanisms in microstructured ZnO random lasers remains poorly understood. In this work, the radiative properties of an array of vertically aligned ZnO microrods, synthesized by a modified thermal evaporation method, were studied. The microrods exhibited lengths up to 60 μm and diameters ranging from 1 to 5 μm. Random lasing from a microrod array was observed in the near-UV range (with a laser emission peak wavelength of ∼391 nm) with a threshold down to 40 kW/cm2 under optical excitation. An analysis of the nature of optical gain in the grown structure was conducted at various temperatures. It was found that at room temperature, two-phonon-assisted exciton recombination is the main process leading to light amplification. [ABSTRACT FROM AUTHOR]

The double-ion chamber (DIC) method has been used to measure photoabsorption cross sections in the ionization region of the sample gas. In this study, we introduce a method to extend the wavelength region of the DIC measurements beyond the ionization threshold wavelength by using the photoion currents from the impurities in the sample gas. To verify this method, the photoabsorption cross sections of C2H2 (ionization threshold wavelength λth = 108.8 nm) have been measured from 105 to 137 nm. The natural impurity, acetone (λth = 127.8 nm), contained 1% in high-purity grade acetylene (C2H2) sample gas, allowing for measurements in the non-ionizing region of C2H2 up to 127.7 nm. By adding 1% benzene (λth = 134.6 nm) in the sample gas, measurements were possible even further, to 134.5 nm. This new method enables the measurement of the photoabsorption cross section by photoions that are produced from the impurities in the sample gas in a substantial amount. The current measurement methodology aligns well with the previous measurements of Suto and Lee [Suto and Lee, J. Chem. Phys. 80, 4824 (1984)]. [ABSTRACT FROM AUTHOR]

Asymmetric quantum wells (AQWs) utilizing interband transitions enhance second-order susceptibility over a wide wavelength range compared to natural crystals. The nonlinear susceptibility is further enhanced in AQWs with type-II band alignment as compared to type-I band alignment, a result of the larger interband charge shift. This enhancement is demonstrated in this work by analyzing three type-I and type-II AQW designs based on the lattice-matched InP/AlGaInAs materials systems using the envelope wavefunction approximation. The calculated interband second-order susceptibility tensor elements in type-II structures range between 20 and 1.60 × 103 pm/V for nearly resonant optical rectification and difference frequency generation applications at near-infrared and terahertz wavelengths, an improvement of nearly 1 order of magnitude over the type-I structures and 1–2 orders of magnitude over natural crystals such as LiNbO3, KTiOPO4 (KTP), or GaAs. A factor of 2–3 further enhancement of the tensor elements is achieved by optimizing the well widths and band offsets of the type-II asymmetric quantum wells. The type-II structure can be implemented in other material systems spanning the longwave infrared to visible wavelengths, enhancing nonlinear susceptibility for various applications, including photonic integrated circuits. [ABSTRACT FROM AUTHOR]

Magic-sized nanocrystals (MSNCs) grow via jumps between very specific sizes. This discrete growth is a possible avenue toward monodisperse nanomaterials that are completely identical in size and shape. In spite of this potential, MSNCs have seen limited study and application due to their poor optical properties. Specifically, MSNCs are limited in their range of emission wavelengths and commonly exhibit poor photoluminescence quantum yields (PLQYs). Here, we report silver doping of CdSe MSNCs as a strategy to improve the optical properties of MSNCs. Silver doping leads to controllable shifts in emission wavelength and significant increases in MSNC PLQYs. These results suggest that doped MSNCs are interesting candidates for displays or luminescent solar concentrators. Finally, we demonstrate that the doping process does not affect the magic size of our MSNCs, allowing further photophysical study of this class of nanomaterial. [ABSTRACT FROM AUTHOR]

Indium tin oxide (ITO) film, which is the most commonly used transparent conductive film (TCF), has traditionally been believed to be transparent in the visible spectrum but to reflect infrared (IR) light beyond the plasma wavelength (λp). However, our theoretical analysis challenges this notion by demonstrating that an ultrathin ITO TCF that is thinner than the light's penetration depth can overcome the transmission barrier at λp. To validate the theoretical modeling, we have successfully fabricated ultrathin ITO films that, despite having λp ≈ 1 μm, remain transparent from 400 nm to 20 μm. This represents the broadest transparency range ever reported for any In2O3-based TCF. The 10-nm-thick ITO TCFs have high visible transmittance (91.0% at 550 nm), low resistivity (5 × 10−4 Ω cm), and good IR transmittance (averaging 60% over 1.35–18.35 μm). Their IR transparency facilitates radiative cooling of the underlying circuitry. When an operational resistor is enclosed by commercial ITO TCFs that are 140 nm thick, its temperature increases. However, using 10-nm-thick ITO TCFs instead of the commercial ones can completely avoid this temperature rise. Moreover, attaching a silver grid to a 10-nm-thick ITO TCF can reduce the effective sheet resistance to ∼10 Ω/□ at the expense of only ∼3% transmittance. This development paves the way for large-scale applications that require low sheet resistance and far-IR transparency. [ABSTRACT FROM AUTHOR]

Faraday polarization rotation control of 1529 nm wavelength has been obtained using the 5 S 1 / 2 → 5 P 3 / 2 → 4 D 5 / 2 transition of rubidium. The traditional off-resonant polarization rotation method commonly used in the Faraday effect for direct transitions of atoms is not applicable to the transitions between excited states. In this study, we proposed a near-resonant polarization rotation method using the Faraday effect between excited states of atoms, by which the polarization rotation of the rubidium 5 P 3 / 2 → 4 D 5 / 2 transition can be controlled from 0 ° to 90 ° with low distortion. The 780 nm pump light corresponding to the 5 S 1 / 2 → 5 P 3 / 2 transition can also be used simultaneously as a control source to manipulate the polarization state of the 1529 nm optical signal. [ABSTRACT FROM AUTHOR]

[Display omitted] The diversity of catalytic products determines the difficulty of selective product modulation, which usually relies on adjusting the catalyst and reaction conditions to obtain different main products selectively. Herein, we synthesized D-π-A-D conjugated organic polymers (TH-COP) using cyclotriphosphonitrile, alkyne, 2H-benzimidazole, and sulfur units as electron donors, π bridges, electron acceptors, and electron donors, respectively. TH-COP exhibited excellent photoinduced carrier separation and redox ability under different visible light wavelengths, and the main products of its CO 2 reduction are CH 4 (1000.0 μmol g−1) and CO (837.0 μmol g−1) under 400–420 nm and 420–560 nm, respectively. In addition, TH-COP could completely convert phenylmethyl sulfide to methyl phenyl sulfone at 400–420 nm and diphenyl disulfide at 480–485 nm in yields up to 95 %. This study presents a novel strategy for the targeted fabrication of various main products using conjugated polymers by simply changing the wavelength range of visible light. [ABSTRACT FROM AUTHOR]

We answer frequently asked questions (FAQs) about the Hellings and Downs correlation curve—the 'smoking-gun' signature that pulsar timing arrays (PTAs) have detected gravitational waves (GWs). Many of these questions arise from inadvertently applying intuition about the effects of GWs on LIGO-like detectors to the case of pulsar timing, where not all of it applies. This is because Earth-based detectors, like LIGO and Virgo, have arms that are short (km scale) compared to the wavelengths of the GWs that they detect ( ≈ 10 2 –104 km). In contrast, PTAs respond to GWs whose wavelengths (tens of light-years) are much shorter than their arms (a typical PTA pulsar is hundreds to thousands of light-years from Earth). To demonstrate this, we calculate the time delay induced by a passing GW along an Earth-pulsar baseline (a 'one-arm, one-way' detector) and compare it in the 'short-arm' (LIGO-like) and 'long-arm' (PTA) limits. This provides qualitative and quantitative answers to many questions about the Hellings and Downs curve. The resulting FAQ sheet should help in understanding the 'evidence for GWs' recently announced by several PTA collaborations. [ABSTRACT FROM AUTHOR]

Effective suppression of dark current is essential for improving the performance of bulk defect-mediated absorption (BDA) photodetectors. Blocked impurity band (BIB) infrared detectors have been developed and utilized from mid-infrared to far-infrared wavelength regions for low noise. In this work, a blocking layer of dark current was applied to a BDA short-wave infrared (SWIR) photodetector, emulating the concept of BIB detectors. ZnO was chosen as the blocking layer to impede the transport of electrons from the bulk defect levels due to its wide bandgap and to allow the photocurrent to remain nearly unaffected by proper positioning of the conduction band minimum. After introducing the ZnO blocking layer, the dark current density of the photodetector was reduced by two orders of magnitude, and the specific detectivity was enhanced by one order of magnitude. The effects of TiO2 and WO3 as blocking layers were also investigated and compared with ZnO. This work offers an effective method for enhancing detectivity in SWIR BDA photodetection by suppressing the dark current efficiently. [ABSTRACT FROM AUTHOR]

Benefiting from low power consumption and high processing speed, there is a growing interest in diffraction neural networks (DNNs), which are typically showcased with 3D printing devices, leading to large volumes, high costs, and low levels of integration. Metasurfaces can desirably manipulate wavefronts of electromagnetic waves, providing a compact platform for mimicking DNNs with novel functions. Although multi‐wavelength and multi‐target recognition provides a richer and more detailed understanding of complex environments, existing architectures are primarily trained to classify a single target at a specific wavelength. A metasurface approach is proposed to design multiplexed DNNs that can classify multiple targets and spatial sequences across various wavelengths in multiple channels. To realize multi‐task processing, the dielectric metasurface is designed based on phase and wavelength multiplexing, which can integrate multi‐target DNNs with different tasks such as operating at distinct wavelengths and classifying diverse targets. The efficacy of this method is exemplified through the numerical simulation and experimental demonstration of recognizing a single target with two wavelengths, two targets at a single wavelength, and two targets at dual wavelengths. This compact metasurface approach enables the design of multi‐target and multi‐wavelength DNNs, opening a new window to develop massively parallel processing and versatile artificial intelligence systems. [ABSTRACT FROM AUTHOR]

Measurements of the longitudinal and transverse spin relaxation times of holes in an ensemble of vertically tunnel‐coupled self‐assembled InAs/In0.53$_{0.53}$Al0.24$_{0.24}$Ga0.23$_{0.23}$As quantum dots (QDs), emitting in the telecom spectral range, are reported. The spin coherence is determined using the spin mode‐locking method in the inhomogeneous ensemble of QDs. Modeling the signal allows us to extract the hole spin coherence time to be in the range of T2=0.02−0.4 $T_{2} = 0.02 - 0.4 \textrm{ } \textrm{ } \mu$μs. The longitudinal spin relaxation time T1=0.5 $T_{1} = 0.5 \textrm{ } \textrm{ } \mu$μs is measured using the spin inertia method. The parameters investigated allow us to suggest that the main relaxation mechanism at low magnetic fields is related to the electron–hole spin exchange. [ABSTRACT FROM AUTHOR]

Finding birefringent material with giant optical anisotropy is urgent for photonic applications. However, the application of existing birefringent materials is limited by restricted transparency wavelength or optical anisotropy. The process of trial and error is time‐consuming and inefficient in terms of resources, especially when compared to the vast design spaces for materials. The immense chemical space necessitates a high‐throughput approach for giant optical anisotropy materials design. Here, a full‐applied wavelength map of birefringent materials is constructed, from conventional visible expanding to ultraviolet and deep‐ultraviolet region by high‐throughput screening methods. And highlighted 579 materials birefringence exceeds the one of available commercial birefringent materials in corresponding regions. Significantly, 54 materials possess giant birefringence above 0.5 @1064 nm. Via developing a high‐throughput screening technique for microscopic structures with given coordination number, the study further characterizes a comprehensive map of functional modules featuring birefringent activeness. According to the macroscopic and microscopic dual‐functional maps, and a novel crystal Li2(HC3N3S3)∙5H2O with birefringence difference 0.532 @546 nm is designed and synthesized successfully. This study identifies desired materials with high performance in unheeded chemical spaces. [ABSTRACT FROM AUTHOR]

Summary: During harvesting, transportation and storage of kiwifruit, the flesh is often bruised by collision or compression. However, the bruises in kiwifruit are extremely difficult to recognise by naked eyes and are called hidden bruises. Accordingly, a fast method for detecting hidden bruises in kiwifruit was developed in this study based on hyperspectral imaging (HSI) coupled with deep learning. The spectral range (924–1277 nm) and feature wavelengths (928.19, 1051.03 and 1190.47 nm) sensitive to hidden bruises in kiwifruit were selected using the principal component analysis (PCA). Subsequently, three‐channel images (Dataset 1), grayscale images (Dataset 2) and pseudo‐colour images (Dataset 3) were generated according to the images of feature wavelengths of the kiwifruit. The YOLOv5s model for detecting the hidden bruised areas of the kiwifruit was developed using these three datasets. The results showed that the YOLOv5s detection model performed best at Dataset 1, and the values of Precision, Recall, F1, mAP and FNR of this model were 98.25%, 97.50%, 97.87%, 99.12% and 2.50% respectively. The study showed that HSI technology combined with the YOLOv5s model can effectively detect hidden bruises in kiwifruit, providing references for detecting hidden bruises in other fruit. [ABSTRACT FROM AUTHOR]

The ability to analyze blunt-force trauma is crucial for deciphering valuable clues concerning mechanisms of injury and as evidence for medico-legal investigations. The use of alternate light sources (ALS) has been studied over the past decade, and is proposed to outperform conventional white light (CWL) during bruise assessments. In response to the growing interest of the technology worldwide, a systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to address the ability of ALS to detect and visualize bruising. From an initial 4055 records identified, ten studies met the eligibly criteria and were selected for this review. Evaluation also included a novel framework, referred to as SPICOT, to further systematically assess both scientific evidence and risk of bias in forensic literature. Analysis reveals that narrowband wavelengths within in the infrared or ultraviolet spectral ranges do not significantly outperform CWL in visualizing or detecting bruising. However, wavelengths within the visible spectrum, particularly 415 nm combined with longpass or bandpass yellow filters, are more effective. However, the majority of selected studies only address the sensitivity of ALS, and therefore, results may only be considered valid when the location of a bruise is known. Further investigation is required to understand the specificity of ALS, in particular how the use of topical cosmetic products, previous wounds/scar-tissue, tattoos, moles and freckles may affect detection. The ethical concern regarding the interpretation of enhanced visualized trauma should also be considered in prospect discussions prior to implementing ALS into routine practice. Nevertheless, this review finds that narrowband ALS within the visible spectrum demonstrates potential for improved injury documentation, outperforming CWL in the detection and visualization of bruising. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to thoroughly describe sensitivity and resolution enhancement by systematically optimizing key parameters in laser-induced breakdown spectroscopy analysis. Simultaneous analysis of biogenic (C, P, Mg, and Ca) and contaminating (Pb) elements, which are commonly detected in selected biotic matrices (mammal teeth), was performed. Hydroxyapatite reference pellets were utilized as model matrices, which successfully reflect human dental tissue. The optimization involved precise adjustments of the used laser wavelengths (1064, 532, and 266 nm), relative defocus of the laser pulse, ablation pulse energies, and gate delays for collecting characteristic spectra. In addition, for Ca analysis, the signals of different ionization line types (Ca I 364.44 nm; Ca II 370.60 and 396.85 nm) were compared; in the case of Pb analysis, the limits of detection were established for each used laser wavelength, and the revealed differences were discussed in detail. We intend to demonstrate the benefits of rapid, low-cost analysis and also the importance of measurement parameters used in biotic sample testing. [ABSTRACT FROM AUTHOR]

The present study investigates electro-osmotically modulated peristaltic transport of third-grade fluid through a microtube taking into consideration the intricate coupling of zeta potential and hydrodynamic slippage. The analytical results encompass the mathematical expressions for dimensionless electrical potential distribution as well as series solutions for stream function and axial pressure gradient up to first order utilizing the perturbation technique for small Deborah number coupled with the Cauchy product for infinite series. Critical values and ranges of wavelength have been obtained where the axial pressure gradient vanishes. Moreover, pivotal values and ranges of wavelength have also been noted for the invariance of pressure gradient with respect to Deborah number as well as Debye-Hückel parameter. Trapping phenomenon has also been investigated by contours of streamlines wherein the zones of recirculation or trapped boluses are formed predominantly near the microtube walls. Additionally, the relative enhancement in hydrodynamic slippage amplifies the trapped bolus size, whereas a diminishing behavior on bolus size is observed by the electro-osmotic parameter. [ABSTRACT FROM AUTHOR]

Rationale Methods Results Conclusions Surface‐assisted laser desorption/ionization (SALDI) mass spectrometry (MS) builds on the use of nanostructured surfaces (e.g., coatings of colloidal nanoparticles) to promote analyte desorption and ionization. The SALDI process is believed to occur mainly through thermal processes, resulting from heating of the nanosubstrate upon absorption of the photon energy, and by assisting ionization steps. Mostly due to the accessibility of the respective hardware, the majority of SALDI‐MS studies use standard laser wavelengths for MALDI (i.e., 337 or 355 nm), even though peak absorption of the SALDI nanosubstrate might completely differ from these values.Here, we investigated the wavelength dependence in SALDI‐MS to determine if wavelength adjustment would be beneficial, and to provide new experimental data for a better understanding of the SALDI mechanism. To this end, gold nanoparticles (AuNPs) sprayed onto microscope glass slides were employed as SALDI nanosubstrates and L‐arginine as a model analyte. In addition, we used 2,5‐dihydroxyacetophenone (2,5‐DHAP) for classical MALDI‐MS using the same experimental setup. Arginine ion signals were recorded as a function of laser wavelength and laser fluence. Mass spectra were acquired in the wavelength range between 310 and 630 nm, including the absorption maximum of the sprayed AuNPs around 550 nm and that of 2,5‐DHAP around 380 nm.Laser fluence thresholds for the generation of arginine ions were found to be dependent on the laser wavelength and to inversely correlate with the absorbance profiles of the deposited AuNPs and 2,5‐DHAP, respectively. Very differently to MALDI, in SALDI ionization efficiency was found to strictly linearly decrease with increasing laser wavelength.Our results, therefore, corroborate the general assumption that material ejection in SALDI‐MS is mainly driven by thermal processes in the low laser fluence range and add new evidence that the ionization process is directly influenced by photon energy when AuNPs are employed as nanosubstrates. [ABSTRACT FROM AUTHOR]

Decoupling of phase and polarization is significant for multidimensional light manipulation. However, this requires traditional cascaded and parallel optical elements, resulting in a bulky and complex system. Metasurfaces can potentially replace complex optical modules as novel ultrathin planar optical elements. Herein, an ultrathin single‐layer metasurface is proposed to decouple the phase and polarization based on the Pancharatnam–Berry phase. The rotation angles of the two nanofins are employed to manipulate the phase and polarization independently, significantly simplifying the design process. Diffraction‐limited focusing with a degree of linear polarization higher than 95% is achieved for wavelengths in the 405–633 nm range. Furthermore, a metasurface can arbitrarily manipulate the relative intensity between different channels. The intensity ratio is adjusted from 0.12 to 6.62. These results will pave the way for miniaturized, integrated, and multi‐channel optical elements. [ABSTRACT FROM AUTHOR]

Cocatalyst loading is of critical importance in efficient photocatalytic water splitting over perovskite oxynitrides. Perovskite CaTaO2N was synthesized for enhancing photocatalytic hydrogen evolution via decoration of a Pt cocatalyst by impregnation–reduction and photodeposition methods. The Pt-loaded CaTaO2N photocatalyst evolves 6.4 μmol H2 per hour, with an apparent quantum yield as high as 0.67% at a wavelength of 420 nm. Decorating the cocatalyst with uniform dispersion and intimate contact onto the surface of narrow-bandgap perovskite oxynitrides is an efficient method to upgrade photocatalytic hydrogen evolution from water splitting. [ABSTRACT FROM AUTHOR]

Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed |$0.1c$|⁠. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman |$\alpha$| forest. We present a catalogue of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are |$243\, {\rm km}\, {\rm s}^{-1}$| smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study. [ABSTRACT FROM AUTHOR]

On-chip integrated photonics with operating wavelength at short-wave infrared region is becoming popular for its potential advantages in extending the telecommunication bandwidth and the application in gas sensing. As an important component of integrated optoelectronic chips, high-performance waveguides have attracted widespread attention. In this work, high-performance Ge waveguides were designed and fabricated on the Ge-on-Si platform, in which germanium films were epitaxially grown by the chemical vapor deposition process. The propagation loss for the waveguide was measured to be 2.34 dB/cm at the wavelength of 2 μm through the cut-back method. The quantitative relationship between the waveguide propagation loss and sidewall roughness as well as material defect density was established by introducing an empirical coefficient m. The m value was calculated to be 3.8 × 10−4 dB for the waveguide with a fixed Ge thickness of 1.5 μm by fitting the experimental propagation loss data at an operating wavelength of 2 μm. This formula provides a significant reference for future design of waveguide dimension structures, where defect induced absorption loss is non-negligible. [ABSTRACT FROM AUTHOR]

The size-dependent emission wavelength shift of micro-scale light emitting diodes (micro-LEDs) has been frequently reported in recent publications, but its underlying physical mechanism has not yet been thoroughly elucidated. Here, we fabricate and characterize the red, green, and blue InGaN micro-LED mesas with different diameters down to 1 μm. As the size decreases, all the samples of different colors show an inverted V-shaped photoluminescence wavelength variation trend, first a red shift and then a blue shift, and the shifting range is larger for samples with longer wavelengths. Micro-Raman spectrum confirms that the stress was significantly released after scaling down the size from epitaxial wafer to 1 μm. The theoretical simulations show that the red and blue shifts are, respectively, attributed to the bandgap narrowing and the weakening of the quantum-confined Stark effect caused by strain relaxation, which dominate successively. [ABSTRACT FROM AUTHOR]

We report the observation and theoretical analysis of photothermal phase modulation in an optical nanofiber (NF) immersed in light-absorbing gas. The phase modulation arises from the contrasting photothermal processes experienced by the mode field within and outside the NF, which exhibits significant wavelength and pressure dependence in the nanoscale waveguides. By designing the diameter of the NF, the photothermal phase modulation can be readily controlled, and a nullification of phase modulation is achieved at a specific wavelength. Experiments on NFs with different diameters demonstrated pressure-controllable phase modulation up to 0.058π rad/mW, potentially allowing the development of nanoscale all-optical modulators and sensors with optimal performance. [ABSTRACT FROM AUTHOR]

We report for the first time the detection of thermal free–free emission from post-flare loops at 34 GHz in images from the Nobeyama Radioheliograph. We studied eight loops, seven of which were from regions with an extremely strong coronal magnetic field reported by Fedenev et al. Loop emission was observed in a wide range of wavelength bands, up to soft X-rays, confirming their multitemperature structure and was associated with noise storm emission in metric λ. The comparison of the 17 GHz emission with that at 34 GHz, after a calibration correction of the latter, showed that the emission was optically thin at both frequencies. We describe the structure and evolution of the loops and we computed their density, obtaining values for the top of the loops between 1 and 6 × 1010 cm−3, noticeably varying from one loop to another and in the course of the evolution of the same loop system; these values have only a weak dependence on the assumed temperature, 2 × 106 K in our case, as we are in the optically thin regime. Our density values are above those reported from EUV observations, which go up to about 1010 cm−3. This difference could be due to the fact that different emitting regions are sampled in the two domains and/or due to the more accurate diagnostics in the radio range, which do not suffer from inherent uncertainties arising from abundances and non-LTE excitation/ionization equilibria. We also estimated the magnetic field in the loop tops to be in the range of 10–30 G. [ABSTRACT FROM AUTHOR]

River bedforms and their deposits—fluvial cross strata— respond to floods. However, it is unclear if all floods are equally represented in cross strata. Here, using a series of physical experiments in which bedforms were subjected to equivalent flood magnitudes over varying durations, we demonstrate the existence of a lower bound on flood durations that are represented in cross strata. We show that the scour depths and preserved set thickness are indistinguishable from baseflow conditions when the rising‐limb duration of floods is shorter than the baseflow‐equilibrated bedform turnover timescale—time required to displace the volume of a single bedform at baseflow conditions. In contrast, scour depth and preserved set thickness distributions deviate from baseflow conditions when flood rising‐limb duration exceeds the baseflow‐equilibrated bedform turnover timescale, causing preferential preservation of falling‐limb bedform dynamics. Our work provides a previously unrecognized quantitative bound on flood durations that are represented in fluvial cross strata. Plain Language Summary: Bedforms are routinely found on sandy riverbeds and their deposits, called fluvial cross strata, are the fundamental building blocks of river deposits. It has long been hypothesized that bedforms respond to floods by changing their shape and speed. In addition, fluvial cross strata are hypothesized to record past floods, thus, providing a key window into past hydrologic variability. However, it is unclear if floods of all durations are equally likely to be represented in bedform morphology and fluvial cross strata. Here, we investigate how floods of different durations are recorded in fluvial cross strata using four physical experiments of bedform evolution. We examine changes in bedform morphology (height, length, speed) and preservation with floods of equal magnitude but varying durations and compare the results with a control experiment with steady water and sediment discharge. Our results reveal a previously unrecognized lower limit on preserved flood duration in cross strata, corresponding to the time required to move a single bedform one wavelength (turnover timescale) in baseflow conditions. Only floods with durations longer than the turnover timescale led to identifiable changes in bedform morphology and fluvial cross strata. These findings advance our ability to better interpret geological records of past floods. Key Points: Experiments show that baseflow‐equilibrated bedform turnover timescale sets the lower bound on preserved flood duration in cross strataFloods with a duration less than this lower bound do not cause a detectable change in preserved set thickness and scour‐depth distributionFloods with duration longer than the lower bound cause scour‐depth deepening and preferential preservation of falling‐limb deposits [ABSTRACT FROM AUTHOR]

Holography is an ideal solution for truly 3D display. Complex‐amplitude hologram can realize high quality reconstructions compared to amplitude‐only hologram and phase‐only hologram. It is difficult for conventional spatial light modulators to achieve complex‐amplitude holographic display while ensuring temporal and spatial resolution, let alone color complex‐amplitude holographic display. Benefiting from the subwavelength pixel size and the powerful multi‐dimensional electromagnetic wave control capabilities, a few metasurface hologram with large viewing angle, high resolution, and no high‐order diffraction crosstalk based on complex‐amplitude control have been studied and realized. Nevertheless, colorful complex‐amplitude metasurface holography at visible frequency has not been implemented yet. Here a complex‐amplitude dual‐wavelength metasurface holography is proposed by using a single cross‐shaped meta‐atom. The polarization conversion efficiency of each wavelength channel is controlled by adjusting the geometric size, while the phase value from 0 to 2π is manipulated based on the Pancharatnam–Berry(PB) phase by rotating the meta‐atom. Without spatial multiplexing, the high‐resolution property of the metasurface is retained. The designed metasurface achieves dual‐color holographic display in the far‐field and the experimental results agree well with the simulation results. The proposed metasurface opens a pathway for high quality color holographic displays and other applications that require complex‐amplitude modulation at different wavelengths. [ABSTRACT FROM AUTHOR]

In this work, layer-by-layer organic photovoltaics (LbL OPVs) were prepared by sequentially spin-coating PM1 and L8-BO solutions. The solvent additive 1,8-diiodooctane (DIO), which has a high boiling point, and solid additive l,3,5-trichlorobenzene (TCB), which has a high volatile, were deliberately selected to incorporate with the L8-BO solutions. The power conversion efficiency (PCE) of LbL OPVs was considerably enhanced from 17.43% to 18.50% by employing TCB as the additive, profiting by the concurrently increased short-circuit current density (JSC) of 26.74 mA cm−2 and a fill factor (FF) of 76.88%. The increased JSCs of LbL OPVs with TCB as additive were ascribed to the tilted-up absorption edge in the long wavelength range and the external quantum-efficiency spectral difference between LbL OPVs with and without TCB as an additive. The molecular arrangement of L8-BO and the PM1 domain was enhanced with TCB as an additive, which was most likely responsible for the increased charge mobilities in the layered films processed with additives. It was indicated that the dynamic film-forming process of the acceptor layers plays a vital role in achieving efficient LbL OPVs by employing additive strategy. Over 6% PCE improvement of the LbL OPVs with PM1/L8-BO as the active layers can be achieved by employing TCB as additive. [ABSTRACT FROM AUTHOR]

Array waveguide gratings (AWGs) have been widely used in multi-purpose and multi-functional integrated photonic devices for Microwave photonics (MWP) systems. In this paper, we compare the effect of output waveguide configurations on the performance of AWGs. The AWG with an output waveguide converging on the grating circle had larger crosstalk and lower nonuniformity. We also fabricated a 1 × 8 AWG with an output waveguide converging onto the SOI's grating circle, whose central operation wavelength was around 1550 nm. The fabricated AWG has a chip size of 500 μm × 450 μm. Experimental results show that the adjacent channel crosstalk is −12.68 dB. The center channel insertion loss, as well as 3 dB bandwidth, are 4.18 dB and 1.22 nm at 1550 nm, respectively. The nonuniformity is about 0.494 dB, and the free spectral range is 19.4 nm. The proposed AWG is expected to play an important role in future MWP systems given its good nonuniformity and insertion loss level. [ABSTRACT FROM AUTHOR]

Perfect absorption with adjustable Q factor and wavelength is essential in both theory and application. To address this issue, a structure composed of an epsilon-near-zero (ENZ)- SiO2 grating and a multilayer dielectric structure was designed. In the structure, the intrinsic loss is related to the ENZ thickness, while the external leakage depends on the grating parameters. By adjusting the ENZ film thickness, the intrinsic loss rate was tuned to match the external leakage rate corresponding to different grating parameters, realizing the critical couplings with different Q factors and wavelengths. Under critical coupling, the absorption rate reached a maximum of 99.999%, demonstrating ultra-perfect absorption. The Q factor was adjusted from 4350 to 35800, and the absorption wavelength was modified from 1050 to 1282 nm. The design work may provide new ideas for developing wavelength- and Q-selective absorbers, optical modulators, dielectric sensors, and photodetectors. [ABSTRACT FROM AUTHOR]

Miniaturized reconstructive spectrometers play a pivotal role in on-chip and portable devices, offering high-resolution spectral measurement through precalibrated spectral responses and AI-driven reconstruction. However, two key challenges persist for practical applications: artificial intervention in algorithm parameters and compatibility with complementary metal-oxide-semiconductor (CMOS) manufacturing. We present a cutting-edge miniaturized reconstructive spectrometer that incorporates a self-adaptive algorithm referenced with Fabry-Perot resonators, delivering precise spectral tests across the visible range. The spectrometers are fabricated with CMOS technology at the wafer scale, achieving a resolution of ~2.5 nm, an average wavelength deviation of ~0.27 nm, and a resolution-to-bandwidth ratio of ~0.46%. Our approach provides a path toward versatile and robust reconstructive miniaturized spectrometers and facilitates their commercialization. [ABSTRACT FROM AUTHOR]

Spintronic terahertz emitters (STEs) are powerful sources of ultra-broadband single-cycle terahertz (THz) field transients. They work with any pump wavelength, and their polarity and polarization direction are easily adjustable. However, at high pump powers and high repetition rates, STE operation is hampered by a significant increase in the local temperature. Here, we resolve this issue by rotating the STE at a few 100 Hz, thereby distributing the absorbed pump power over a larger area. Our approach permits stable STE operation at a fluence of ∼1 mJ/cm2 with up to 18 W pump power at megahertz repetition rates, corresponding to pump-pulse energies of a few 10 μJ and pump power densities approaching 1 kW/cm2. The rotating STE is of interest for all ultra-broadband high-power terahertz applications requiring high repetition rates. As an example, we show that terahertz pulses with peak fields of 10 kV/cm can be coupled to a terahertz-light wave-driven scanning tunneling microscope at 1 MHz repetition rate, demonstrating that the rotating STE can compete with standard terahertz sources such as LiNbO3. [ABSTRACT FROM AUTHOR]

Two novel aza-BODIPY based anion sensors, decorated with halogen bonding recognition sites, are capable of detecting halide anions at biologically-relevant near-IR wavelengths. With potential application for improving the selectivity of photodynamic therapy agents, unprecedented supramolecular host–guest anion binding-modulated singlet oxygen generation is demonstrated. [ABSTRACT FROM AUTHOR]

Different types of devices with modulable resistance are attractive for the significant potential applications such as sensors, information storage, computation, etc. Although extensive research has been reported on resistance effects, there is still a need for exploring new mechanisms that offer advantages of low power consumption, high sensitivity, and long-term stability. Here, we report a graphene–Si based spatial-dependence photo-rheostat (SDPR), which enables bipolar resistance modulation in the range of 5 mm with a resistance sensitivity exceeding 1,000 Ω/mm at operating wavelengths from visible to near infrared band (1,550 nm). Especially, at ultra-low energy consumption, the device can achieve modulation of even 5 orders of magnitude of resistance and response speed up to 10 kHz. A theoretical model based on carrier dynamics is established to reveal the diffusion and drift of carriers as a mechanism explaining such experimental phenomenon. This work provides a new avenue to modulate resistance at low power consumption as novel opto-potentiometers in various photoelectric applications. [ABSTRACT FROM AUTHOR]

Position‐sensitive detectors (PSDs) are widely used in optical inspection applications, such as precise measurement of distance and angle, surface profiling, and motion tracking, etc. The lateral photovoltaic effect is the mechanism employed by most PSDs to determine position, but its gain‐free nature hinders weak‐light detection and applications. Here, a new position recognition mechanism with an intrinsic high gain is proposed and employ it to design a weak‐light and large‐size photoconductor‐type PSD. The position recognition is established by the intrinsic link between the gain and channel length in a photoconductor, and the designed linear correlation between the channel length and position. The photoconductor‐type graphene/Si PSD based on the recognition mechanism shows an active length of over 1 mm, a high spatial position resolution at the sub‐micrometer level, and a low detection limit power of 100 pW. Compared with Si PSDs, the gain of the photoconductor‐type PSD is improved by 3–4 orders of magnitude. In addition, the operational wavelength range of the PSD is expanded to include the near‐infrared region, specifically at 1300 and 1550 nm. The new position recognition mechanism paves the way for the development of ultra‐sensitive light position detection. [ABSTRACT FROM AUTHOR]

We present exponential wave integrator Fourier pseudospectral (EWI‐FP) methods and establish their error estimates of the fully discrete schemes for the Dirac equation in the massless and nonrelativistic regime. This regime involves a small dimensionless parameter where 0<ε≤1$$ 0<\varepsilon \le 1 $$, and ε$$ \varepsilon $$ is inversely proportional to the speed of light. The solution exhibits highly oscillatory behavior in time and rapid wave propagation in space in this regime. Specifically, the time oscillations have a wavelength of O(ε)$$ O\left(\varepsilon \right) $$, while the spatial oscillations have a wavelength of O(1)$$ O(1) $$, with a wave speed of O(ε−1)$$ O\left({\varepsilon}^{-1}\right) $$. We employ (symmetric) exponential wave integrators for temporal derivatives and Fourier spectral discretization for spatial derivatives. We rigorously derive the error bounds which explicitly depend on the mesh size h$$ h $$, the time step τ$$ \tau $$ and the small dimensionless parameter ε$$ \varepsilon $$. The error estimates for the EWI‐FP methods demonstrate that their meshing strategy requirement (ε$$ \varepsilon $$‐scalability) necessitates setting h=O(1)$$ h=O(1) $$ and τ=O(ε)$$ \tau =O\left(\varepsilon \right) $$ when 0<ε≪1$$ 0<\varepsilon \ll 1 $$. Finally, some numerical examples are provided to validate the error bounds. [ABSTRACT FROM AUTHOR]

Multicolor tuning of persistent luminescence has been extensively studied by deliberately integrating various luminescent units, known as activators or chromophores, into certain host compounds. However, it remains a formidable challenge to fine-tune the persistent luminescence spectra either in organic materials, such as small molecules, polymers, metal-organic complexes and carbon dots, or in doped inorganic crystals. Herein, we present a strategy to delicately control the persistent luminescence wavelength by engineering sub-bandgap donor-acceptor states in a series of single-phase Ca(Sr)ZnOS crystals. The persistent luminescence emission peak can be quasi-linearly tuned across a broad wavelength range (500–630 nm) as a function of Sr/Ca ratio, achieving a precision down to ~5 nm. Theoretical calculations reveal that the persistent luminescence wavelength fine-tuning stems from constantly lowered donor levels accompanying the modified band structure by Sr alloying. Besides, our experimental results show that these crystals exhibit a high initial luminance of 5.36 cd m−2 at 5 sec after charging and a maximum persistent luminescence duration of 6 h. The superior, color-tunable persistent luminescence enables a rapid, programable patterning technique for high-throughput optical encryption. Persistent luminescence is typically confined to discrete wavelengths. Here, the authors can fine tune emission color from green to orange through blending isostructural compounds in single-phase Ca(Sr)ZnOS crystals. [ABSTRACT FROM AUTHOR]

We obtained crystals of novel supramolecular compounds with cucurbit[6]uril which contain aquanitrato complexes of mixed lanthanides. The supramolecular approach was used to produce compounds exhibiting multicolor emission. An X-ray diffraction study demonstrated that the compounds have the following compositions: [{Ln 10.5 Ln 20.5 (H2O)5(NO3)}2CB[6]](NO3)4·HNO3·nH2O (Ln1 = Eu, Ln2 = Pr (1), Nd (2), Sm (3), Gd (4), Tb (5) Dy (6), Er (8)), [{Ln 10.7 Ln 20.3 (H2O)5(NO3)}2CB[6]](NO3)4·HNO3·nH2O (Ln1 = Eu, Ln2 = Ho (7)) and 2[Ln 10.5 Ln 20.5 (H2O)8](NO3)3·CB[6]·2HNO3·mH2O (Ln1 = Eu, Ln2 = Yb (9)). The luminescence properties of compounds 1–9 were investigated in the solid state. The color purity of compound 6 is very close to zero, so it is well suited for white-light generation and can be used for WLED applications. A cool white LED device was fabricated by combining the supramolecular compound 6 and a UV LED chip (365 nm) at a voltage of 3.0 V; the CIE, CCT and CP were (0.328; 0.313), 5736 K and 2%, respectively. Compounds 5 and 6 have different glow colors when irradiated with different wavelengths; modulation of light emission in such compounds can be used to protect against counterfeiting. [ABSTRACT FROM AUTHOR]

In this paper, a Raman laser is proposed based on a high-Q silica microcavity, and arbitrary wavelength tuning is realized by fine and coarse tuning. The mechanical tuning range is extended to 5.5 GHz by designing the geometry of the microcavity. Axial discrete tuning in a wideband range is achieved by coupling different transverse modes. The wavelength of the Raman laser is tuned arbitrary in a range of 38.6 nm with the tuning accuracy about 50 MHz. This study extends the application of microcavity Raman laser to the field of tunable lasers and high dynamic range sensors. [ABSTRACT FROM AUTHOR]

Accurate assessment of food freshness is critical to maintaining human health. However, the complex environment of food usually leads to false‐positive measurements result. Therefore, the development of sensing platforms with self‐calibration for accurate detection of food freshness in complex environments is essential. Here, using the green fluorescence‐emitting FITC‐ene and the red fluorescence‐emitting DBA‐ene‐Eu3+ as fluorescent units, fluorescent polymeric materials P1‐P4 with excitation wavelength‐dependent (254 and 365 nm, matched with standard UV lamp) emission are prepared. P1‐P4 responded rapidly to biogenic amines (BAs). Among them, P3 exhibits the widest linear range, and the most noticeable fluorescence color change (from orange‐red to yellow‐green) under 254 nm excitation and enhanced green fluorescence under 365 nm excitation. The changes of P3‐prepared labels at different excitation wavelengths can be utilized to rapidly evaluate the food's freshness. Furthermore, by using a smartphone to read the Red/Green/Blue values of the labels, the total volatile basic nitrogen (TVBN) values can be output to quantitatively evaluate the food freshness, and the output TVBN values at different excitation wavelengths are utilized for mutual calibration to improve the accuracy of the estimation results. This self‐calibrating sensing platform is fast and nondestructive, which provides an effective method for the accurate evaluation of food freshness. [ABSTRACT FROM AUTHOR]

ABSTRACT A robust method for multiplicative scatter correction (MSC) in infrared spectroscopy is presented. Using quantile regression, the outlier wavelengths (concentration‐dependent wavelengths) that are irrelevant to the regression are identified and therefore excluded from the regression model. This new MCS method, which could be implemented in its simple or extended form, is much simpler than the recently proposed methods and has only one hyperparameter (the quantile value) to be adjusted. To achieve this, a scoring function based on residual analysis can automatically determine the correct quantile value. The method is first explained using simulation data sets and then its validation is explained by analysing some experimental data sets. It was found that our new method can perform well in the presence of strong outlying variables. On the other hand, when the data sets are not associated outlying wavelengths, this method behaves similarly to the conventional MSC method. [ABSTRACT FROM AUTHOR]

Over the past decade, significant advancements in high-resolution imaging technology have been driven by the miniaturization of pixels within image sensors. However, this reduction in pixel size to submicrometer dimensions has led to decreased efficiency in color filters and microlens arrays. The development of color routers that operate at visible wavelengths presents a promising avenue for further miniaturization. Despite this, existing color routers often encounter severe interpixel crosstalk, around 70 %, due to the reliance on periodic boundary conditions. Here, we present interpixel crosstalk-minimized color routers that achieve an unprecedented in-pixel optical efficiency of 87.2 % and significantly reduce interpixel crosstalk to 2.6 %. The color routers are designed through adjoint optimization, incorporating customized incident waves to minimize interpixel crosstalks. Our findings suggest that our color router design surpasses existing color routing techniques in terms of in-pixel optical efficiency, representing a crucial step forward in the push toward commercializing the next generation of solid-state image sensors. [ABSTRACT FROM AUTHOR]

The free electron spin dynamics in Kapitza–Dirac (KD) effect had been studied theoretically in one-dimensional standing wave of EUV to X-ray laser with extremely high intensity, which is far beyond experimental realization. Here, we propose to achieve the free electron spin-dependent KD effect in two-dimensional triangular optical lattice with spatial inversion symmetry breaking, and the theoretical results reveal that laser with wavelength in visible or near-IR and five orders of magnitude decreased intensity could lead to obvious spin-dependent KD effect. This work provides the way to realize the free electron spin-dependent KD effect experimentally. [ABSTRACT FROM AUTHOR]

This letter presents a grounded coplanar waveguide (GCPW) slow‐wave transmission line (SWTL) with an improved wavelength reduction technique by adopting capacitor array. By cross‐interleaving additional capacitors between a signal line and side ground planes, the total capacitance in the capacitor array increases approximately two times compared to the conventional structure, allowing designers to choose a smaller signal conductor's width for higher inductance, thus, improving wavelength reduction performance while preserving the same characteristic impedance. At the 150 GHz frequency of interest, the proposed GCPW SWTL shows approximately 20% and 62.16% reduction in wavelength compared to the reported GCPW SWTL and regular CPW, respectively, with the same 35Ω $35\,{\rm{\Omega }}$ characteristic impedance. To prove the effectiveness of the proposed SWTL concept, the proposed GCPW SWTL test patterns are fabricated in a 65 nm CMOS process. [ABSTRACT FROM AUTHOR]

We report the design, fabrication, and experimental results of an optical wavelength demultiplexer for a new wireless-optical signal converter for Beyond-5G/6G mobile communication system. This optical wavelength demultiplexer is based on a lithium niobate (LiNbO3) multimode interference (MMI) coupler and is intended to be applied in an advanced electro-optics modulator (EOM) with ability in converting the space division multiplexing (SDM) wireless-wavelength division multiplexing (WDM) optical signals. The designed MMI coupler displays a high splitting ratio over -13 dB in both O and L bands. The results from the experiments align well with the simulation. The utilization of the MMI coupler in EOM enables the direct conversion of SDM wireless signals to WDM optical signals, without any additional power supply. The modification of the characteristic of a constructed MMI coupler can be achieved by controlling of the applied voltage of the device. [ABSTRACT FROM AUTHOR]

Two stereoisomers of bicyclic ladder oligosilanes bearing phenyl and tert‐butyldimethylsilyl groups were synthesized, and their structures and electronic properties are compared with a previously reported perisopropyl‐substituted analog. These novel ladder oligosilanes have highly twisted structures with the twist angles between the two terminal Si−Si bonds of av. 37.7 and 39.8°. The UV spectra of these compounds show bathochromically shifted absorption maxima with the longest wavelength compared with that of the perisopropyl‐substituted bicyclic ladder oligosilane. The electronic properties of the ladder oligosilanes were analyzed by theoretical calculations. [ABSTRACT FROM AUTHOR]

Photonic neuromorphic computing is a competitive paradigm to overcome the bottleneck of von Neumann architectures. Incoherent and coherent synaptic networks are two popular schemes realizing photonic weighting functions. Previous works have proved the distributed feedback (DFB) laser with an intracavity saturable absorber (DFB‐SA) can behavior like a spiking neuron. However, the compatibility with the incoherent synaptic architecture has not yet been demonstrated. Here the neuron‐like dynamics of a DFB‐SA laser subject to single‐wavelength and multiple‐wavelengths incoherent optical injections are experimentally demonstrated. The results show that, for the DFB‐SA laser subject to single‐wavelength incoherent injection, the neuron‐like dynamics including threshold, temporal integration, and refractory period are achieved. Besides, the range of injection wavelength that leads to a successful neuron‐like response is identified. For the DFB‐SA laser with four‐wavelength incoherent optical injection, the neuron‐like dynamics can also be achieved. In addition, the effect of wavelength interval is also considered. The logic XOR operation and Iris recognition tasks are successfully implemented. Furthermore, the feasibility of a cascaded system for the DFB‐SA lasers with four‐wavelengths incoherent optical injection is demonstrated. This work provides a feasible scheme for the system integration of photonic spiking neurons and incoherent synaptic networks. [ABSTRACT FROM AUTHOR]

In this article, coherent manipulation of conductivity-dependent sensitivity of the surface plasmon polariton waves(SPPs) is theoretically investigated at the interface of silver metal and conductive atomic medium based on grating geometry using wavelength interrogation. It is reported that the sensitivity of SPPs depends on the phase and amplitude of the complex conductivity of the conductive atomic medium as well as the parameters of driving fields. The conductivity-dependent wavelength interrogation of sensitivity with respect to the refractive index is written as d λ / d n d (σ) and is a function of complex conductivity. A useful control in sensitivity is investigated with variation of phase and amplitude of complex conductivity as well as probe and control field detunings and Rabi frequency as well as decay rates. The order of diffraction and grating period play an important role in the manipulation of the sensitivity. The sensitivity increases with increasing grating period and decreases with increasing order of diffraction. A maximum value of sensitivity is reported to 600 nm/RIU with amplitude and phase of complex conductivity. The reported results have benefits in sensor devices and plasmonster technology. [ABSTRACT FROM AUTHOR]

While considerable research has addressed flow around stationary sinusoidal wavy cylinders, studies on vortex-induced vibration (VIV) of elastic-supported wavy cylinders still remain limited. This study aims to address this gap through a series of water tunnel experiments, focusing on the effects of the cylinder's spanwise wavelength. Three typical spanwise wavelengths (λ* = 1.8, 3.6, and 6.0) are considered, with the first and third identified as the optimal for reducing fluid forces (lift forces by over 90%) in previous stationary cylinder studies. The cylinder oscillates transversally at a range of reduced velocities Ur = 3.0–12.0, corresponding to the Reynolds numbers (1.5–7.0) × 103. Results indicate that, compared with a smooth cylinder, the λ* = 1.8 cylinder experiences reduced oscillation throughout the VIV regime, while the cylinders with λ* = 3.6 or 6.0 undergo enhanced oscillation over a broader lock-in range. The oscillation of the wavy cylinders with λ* = 3.6 or 6.0 tend to occur at a higher Ur, leading to an extension of the lower branch. Frequency analysis shows that, despite affecting vibration amplitude, the wavy surface retains typical VIV features. These results reveal a notable dependence of fluid forces and force-displacement phase lag on the cylinder's wavelength. Finally, we provide a detailed discussion of the phase-averaged and time-averaged flow structures from the time-resolved particle image velocimetry measurement. Overall, this study addresses the research gap concerning the impact of wavelength on the behavior of elastically supported wavy cylinders, providing significant insights for the development of practical strategies for VIV suppression and enhancement. [ABSTRACT FROM AUTHOR]

The development of the Automated Agricultural Cabinet (AAC) prototype was driven by the goal of improving the aromatic qualities of locally grown rice. This compact prototype, designed with attention, employed Arduino programming to investigate genes related to the production of aromatic compounds in rice seedlings under different light conditions, including red, blue and white light. To ensure the reliability of experiments, a controlled environment was maintained at 25 °C and 75 % humidity, and rigorous testing confirmed precise light intensity measurements within the AAC. Results indicated specific light values: 9.25 ± 0.602 for red light, 11.47 ± 0.055 for blue light and 0.91 ± 0.027 µmol·m-²·s-1 for white light. The study focused on up-regulated genes in 7-day-old 'Hom Bon' rice seedlings, revealing a significant increase in P5CS and 1Δ-pyrroline gene expression. These genes are crucial in the biosynthesis pathway of 2-acetyl-1-pyrroline (2-AP), with P5CS acting as a precursor and 1Δ-pyrroline as the final step. Interestingly, the study discovered that when 7-day-old 'Hom Bon' rice seedlings were exposed to both red and blue light, gene expression rose dramatically, contrasting when exposed to white light. This finding demonstrates that the wavelength of light exposure influences gene expression in the 2-acetyl-1-pyrroline (2-AP) biosynthetic pathway of 'Hom Bon' rice seedlings throughout the 7-day growth stage. This study demonstrates the feasibility of improving the smell of indigenous rice varieties by changing pre-planting light conditions, giving a promising avenue for increased commercial appeal. Furthermore, this project aims to improve the local community's financial well-being by supporting better farming methods. [ABSTRACT FROM AUTHOR]