Tandem neural network-assisted inverse design of highly efficient diffractive slanted waveguide grating.

Virtual reality devices featuring diffractive grating components have emerged as hotspots in the field of near-to-eye displays. The core aim of our work is to streamline the intricacies involved in devising the highly efficient slanted waveguide grating using the deep-learning-driven inverse design technique. We propose and establish a tandem neural network (TNN) comprising a generative flow-based invertible neural network and a fully connected neural network. The proposed TNN can automatically optimize the coupling efficiencies of the proposed grating at multi-wavelengths, including red, green, and blue beams at incident angles in the range of 0°-15°. The efficiency indicators manifest in the peak transmittance, average transmittance, and illuminance uniformity, reaching approximately 100%, 92%, and 98%, respectively. Additionally, the structural parameters of the grating can be deduced inversely based on the indicators within a short duration of hundreds of milliseconds to seconds using the TNN. The implementation of the inverse-engineered grating is anticipated to serve as a paradigm for simplifying and expediting the development of diverse types of waveguide gratings.

Hybrid integrated thin-film lithium niobate-silicon nitride electro-optical phased array incorporating silicon nitride grating antenna for two-dimensional beam steering.

This study proposes a solid-state two-dimensional beam-steering device based on an electro-optical phased array (EOPA) in thin-film lithium niobate (TFLN) and silicon nitride (SiN) hybrid platforms, thereby eliminating the requirement for the direct etching of TFLN. Electro-optic (EO) phase modulator array comprises cascaded multimode interference couplers with an SiN strip-loaded TFLN configuration, which is designed and fabricated via i-line photolithography. Each EO modulator element with an interaction region length of 1.56 cm consumed a minimum power of 3.2 pJ/π under a half-wave voltage of 3.64 V and had an estimated modulation speed of 1.2 GHz. Subsequently, an SiN dispersive antenna with a waveguide grating was tethered to the modulator array to form an EOPA, facilitating the out-of-plane radiation of highly defined near-infrared beams. A prepared EOPA utilized EO phase control and wavelength tuning near 1550 nm to achieve a field-of-view of 22° × 5° in the horizontal and vertical directions. The proposed hybrid integrated platform can potentially facilitate low-power and high-speed beam steering.

Dual-Functional Ru/Ni-B-P Electrocatalyst Toward Accelerated Water Electrolysis and High-Stability.

Development of advanced electrocatalysts for the green hydrogen production by water electrolysis is an important task to reduce the climate and environmental issues as well as to meet the future energy demands. Herein, Ru/Ni-B-P sphere electrocatalyst is demonstrated by a combination of hydrothermal and soaking approaches, meeting the industrial requirement of low cell voltage with stable high-current operation. The Ru/Ni-B-P sphere catalyst demonstrates low overpotentials of 191 and 350 mV at 300 mA cm-2 with stable high current operation, ranking it as one of the best oxygen evolution reaction (OER) electrocatalysts. The bifunctional 2-E system demonstrates a low cell voltage of 2.49 V at 2000 mA cm-2 in 6 m KOH at 60 °C of harsh industrial operation condition. It also demonstrates outstanding stability with continuous 120 h (5 days) CA operation at 1000 mA cm-2. Further, the hybrid configuration of Ru/Ni-B-P || Pt/C being paired with the conventional benchmark electrode demonstrates a record low 2-E cell voltage of 2.40 V at 2000 mA cm-2 in 6 m KOH and excellent stability at high current of 1500 mA cm-2 under industrial operational condition.

Switchable optical trapping based on vortex-pair beams generated by a polarization-multiplexed dielectric metasurface.

Optical trapping is a state-of-the-art methodology that plays an integral role in manipulating and investigating microscopic objects but faces formidable challenges in multiparticle trapping, flexible manipulation, and high-integration applications. In this study, we propose and demonstrate a switchable optical scheme for trapping microparticles incorporating disparate vortex-pair beams generated by a polarization-multiplexed metasurface. The miniaturized all-dielectric metasurface, which comprises an array of titanium dioxide nanoposts, was manufactured and characterized to provide polarization-tuned two-fold vortex-pair beams. The profiles of the created vortices can be flexibly tailored by adjusting the combination of topological charges and the separation among phase singularities. Under transverse electric polarized light conditions, a vortex-pair beam with opposite topological charge combinations traps a single microparticle within one beam spot, while under transverse magnetic polarization conditions, two microparticles are captured simultaneously by a vortex-pair beam with the same topological charge signs. The proposed switchable trapping scheme (incorporating a vortex-pair light beam) is expected to feature enhanced integration and flexible manipulation of multiple particles with potential applications in biophysics, nanotechnology, and photonics.

High-performance optical phased array for LiDARs demonstrated by monolithic integration of polymer and SiN waveguides.

Optical phased array (OPA) beam scanners for light detection and ranging (LiDAR) are proposed by integrating polymer waveguides with superior thermo-optic effect and silicon nitride (SiN) waveguides exhibiting strong modal confinement along with high optical power capacity. A low connection loss of only 0.15 dB between the polymer and SiN waveguides was achieved in this work, enabling a low-loss OPA device. The polymer-SiN monolithic OPA demonstrates not only high optical throughput but also efficient beamforming and stable beam scanning. This novel integrative approach highlights the potential of leveraging heterogeneous photonic materials to develop advanced photonic integrated circuits with superior performance.

Inverse design of optical lenses enabled by generative flow-based invertible neural networks.

Developing an optical geometric lens system in a conventional way involves substantial effort from designers to devise and assess the lens specifications. An expeditious and effortless acquisition of lens parameters satisfying the desired lens performance requirements can ease the workload by avoiding complex lens design process. In this study, we adopted the Glow, a generative flow model, which utilizes latent Gaussian variables to effectively tackle the issues of one-to-many mapping and information loss caused by dimensional disparities between high-dimensional lens structure parameters and low-dimensional performance metrics. We developed two lenses to tailor the vertical field of view and magnify the horizontal coverage range using two Glow-based invertible neural networks (INNs). By directly inputting the specified lens performance metrics into the proposed INNs, optimal inverse-designed lens specifications can be obtained efficiently with superb precision. The implementation of Glow-assisted INN approach is anticipated to significantly streamline the optical lens design workflows.

Intraoral approach for the treatment of non­infiltrating angiolipoma of the floor of the mouth in an elderly patient: A case report with review of the literature.

A 75-year-old male patient visited Gangneung-Wonju National University Dental Hospital (Gangneung, South Korea) with a 35-mm fluctuant lesion on the floor of the mouth. It was a dome-shaped exophytic lesion with its top on Wharton's duct orifice area. The encapsulated lesion was excised cautiously and the final diagnosis was non-infiltrating angiolipoma. To the best of our knowledge, this is the first report of an intraoral approach for the treatment of a non-infiltrating angiolipoma on the floor of the mouth in an elderly patient. Differentiating it from a ranula is essential for the surgical approach and, as there is a higher transition to infiltrating angiolipoma, definite treatment should be considered in elderly patients.

Highly Efficient Refractive Index Sensor Based on a Dual-Side Polished SMS Fiber Enabled by Femtosecond Laser Writing.

Fiber-optic refractive index (RI) sensors based on wavelength-shift-based interrogation continue to present a challenge in achieving high sensitivity for a wide detection range. In this paper, we propose a sensor for determining the RI of liquids based on femtosecond laser (fs-laser) writing of a dual-side polished singlemode-multimode-singlemode (SMS) fiber. The proposed sensor can determine the RI value of a surrounding liquid by detecting the dip wavelength in the transmission spectrum of the light propagating through the sensing area. The high RI sensitivity is attributed to the increased interaction area established by the fs-laser, which creates hydrophilic surfaces and maintains the wide detection range of the SMS structure. The results of the wavelength-shift-based interrogation reveal that the fabricated device exhibited a high sensitivity of 161.40 nm per refractive index unit (RIU) over a wide RI detection range of 0.062 RIU. The proposed device has high processing accuracy and a simple manufacturing process. Hence, it has the potential to be used as a lab-on-fiber sensing platform in chemical and biotechnological applications.

Direct CVD Growth of Transferable 3D Graphene for Sensitive and Flexible SERS Sensor.

Three-dimensional (3D) graphene (Gr) has been successfully grown on a patterned sapphire substrate (PSS) with very low mismatch between Gr and the sapphire nanostructure through metal-catalyst-assisted chemical vapor deposition (CVD). However, the transfer of the 3D Gr film without compromising the structural integrity of Gr is challenging because of the low etching rate of PSS. For easy and high-quality transfer of 3D Gr, we propose to coat a transfer-support layer (TSL) on PSS before direct CVD growth of 3D Gr. The TSL is directly deposited on PSS by atomic layer deposition without causing any structural changes in the substrate, as verified through atomic force microscopy (AFM). Few-layer 3D Gr is conformally produced along the surface of the TSL/PSS and successfully transferred onto a flexible substrate through wet-etching transfer, as confirmed by scanning electron microscopy, AFM, and Raman spectroscopy studies. We also present the fabrication of a sensitive and flexible surface-enhanced Raman scattering sensor based on 3D Gr on PMMA with high detection performance for low concentrations of R6G (10-9 M). The proposed transfer method with TSL is expected to broaden the use of 3D graphene in next-generation device applications.

Monolithic integration of polymer waveguide phase modulators with silicon nitride waveguides using adiabatic transition tapers.

Polymer waveguide phase modulators (PMs) demonstrate high thermal confinement with outstanding thermo-optic properties and can provide stable low-power phase modulation in optical phased arrays (OPA). On the other hand, silicon nitride (SiN) waveguides produce stronger optical confinement with smaller waveguide core sizes than polymer waveguides and can handle high optical power without nonlinear effects. In this work, a high-performance PM was achieved by monolithic integration of a polymer waveguide and tapered SiN input and output waveguides. The integration of heterogeneous waveguide materials on a single substrate will enable the fabrication of efficient OPAs for advanced imaging, display, sensing, and communications applications.

Dispersive silicon-nitride optical phased array incorporating arrayed waveguide delay lines for passive line beam scanning.

As optical phased arrays (OPAs), used as solid-state beam scanning elements, swiftly stride towards higher efficiency and faster scanning speed, the line beam scanner is emerging as a viable substitute for its counterpart relying on point-beam-incorporated raster scanning. However, line-beam scanners require active phase shifters for beam scanning; thus, they consume more power and have complex device designs. This study proposes and demonstrates a dispersive silicon-nitride OPA that allows for passive wavelength-tuned steering of a line beam with an elongated vertical beamwidth. To steer the line beam passively covering the two-dimensional field of view, we deployed an array of delay lines with progressive delay lengths across adjacent channels. Furthermore, adiabatic tapers that allow precise effective array aperture adjustment are used as emitter elements to flexibly realize different vertical beamwidths. Combinations of different delay-length differences and taper tip-widths resulted in beam coverage (lateral × vertical) ranging from 6.3° × 19° to 23.8° × 40° by tuning the wavelength from 1530 to 1600 nm. The main lobe emission throughput was as small as - 2.8 dB. To the best of our knowledge, the embodied OPA is the first demonstration of a passive line beam scanner facilitating an adjustable beam coverage with quick operation and enhanced efficiency.

Perovskite solar cells integrated with blue cut-off filters for mitigating light-induced degradation.

The stability of methylammonium (MA)-based perovskite solar cells (PSCs) remains one of the most urgent issues that need to be addressed. Inherent weak binding forces between MAs and halides cause the perovskite structure to become unstable under exposure to various external environmental factors such as moisture, oxygen, ultraviolet radiation, and heat. In particular, the degradation of perovskite films under light exposure accelerates the deterioration of the device, mainly due to the migration of halide ions. In this study, we investigated the effect of light energy on the degradation of inverted PSCs by introducing red ( = 610-800 nm), green (500-590 nm), and blue (300-500 nm) light-pass filters. After 30 h, the inverted PSCs of blue-light-induced devices retained a power conversion efficiency (PCE) of 70%, while those of the green and red light-induced devices retained PCEs of 85% and 90%, respectively. Direct evidence of light-induced degradation was obtained by investigating morphological changes in the perovskite films and the amount of ion accumulation on the Ag electrode. This evidence highlights the varying effect of light with different energies on device degradation. Furthermore, to minimize light-induced device degradation, we designed two types of blue cut-off filters that can selectively block light ranging from = 400 to 500 nm, comprising a multilayered inorganic metasurface. An optical simulation was used to optimize the performance of the designed filters. By investigating the changes in the photovoltaic parameters and the amount of ion accumulation on the Ag electrode, we confirmed that integrating blue cut-off filters into PSCs greatly improved the operational lifetime of the devices.

MicroRNA-18a regulates the metastatic properties of oral squamous cell carcinoma cells via HIF-1α expression.

BACKGROUND: Rapid metastasis of oral squamous cell carcinoma (OSCC) is associated with a poor prognosis and a high mortality rate. However, the molecular mechanisms underlying OSCC metastasis have not been fully elucidated. Although deregulated expression of microRNA (miRNA) has a crucial role in malignant cancer progression, the biological function of miRNA in OSCC progression remains unclear. This study aimed to investigate the function of miRNA-18a in OSCC metastatic regulation via hypoxia-inducible factor 1α (HIF-1α). METHODS: miRNA-18a-5p (miRNA-18a) expressions in patients with OSCC (n = 39) and in OSCC cell lines (e.g., YD-10B and HSC-2 cells) were analyzed using quantitative real-time polymerase chain reaction. HIF-1α protein expressions in OSCC cells treated with miRNA-18a mimics or combined with cobalt chloride were analyzed using western blotting. The miRNA-18a expression-dependent proliferation and invasion abilities of OSCC cells were analyzed using MTT assay, EdU assay, and a Transwell® insert system. RESULTS: miRNA-18a expression was significantly lower in OSCC tissue than in the adjacent normal tissue. In OSCC cell lines, HIF-1α expression was significantly decreased by miRNA-18a mimic treatment. Furthermore, the migration and invasion abilities of OSCC cells were significantly decreased by miRNA-18a mimics and significantly increased by the overexpression of HIF-1α under hypoxic conditions relative to those abilities in cells treated only with miRNA-18a mimics. CONCLUSIONS: miRNA-18a negatively affects HIF-1α expression and inhibits the metastasis of OSCC, thereby suggesting its potential as a therapeutic target for antimetastatic strategies in OSCC.

Multilevel Anti-Counterfeiting Based on Covert Structural Features Embedded in Femtosecond-Laser-Treated Gold Nanocluster/Graphene Hybrid Layer.

The conventional nanoscale anti-counterfeiting scheme, exhibiting limited encoding capacity, faces growing challenges of being falsified with the advent of advanced high-resolution equipment. In this study, we propose a multilevel anti-counterfeiting device based on a femtosecond laser (fs-laser) treated plasmonic gold nanocluster/graphene (AuNC/Gr) hybrid structure integrated with a resonant cavity. The covert structural features encoded in random colored patterns, optical reflection spectra, and Raman spectra constitute three classes of anti-counterfeiting signatures, which originate from the AuNC-covered Gr, which initiates plasmonic and thermal couplings. The attendant inverted thermal distribution is presumed to confine the structural features to the AuNC-Gr interface while leaving no detectable traces on the surface of AuNC/Gr even under advanced high-resolution equipment. Therefore, the proposed approach achieves multilevel anti-counterfeiting accomplishing physically unclonable functions in the form of random colored patterns, reflection spectra, and Raman spectra. As the first report for realizing remarkable optical modulation (i.e., random colored patterns) without any surface trace or damage via fs-laser-AuNC/Gr interaction, our study also discloses the outstanding performance of Gr in fs-laser-induced optothermoplasmonic lithography on near-percolation metal films. Simultaneously, the demonstrated fs-laser-processed plasmonic hybrid structure in conjunction with a resonant cavity is anticipated to expand the encoding capabilities for nanoscale anti-counterfeiting while avoiding the risk of being imitated because of the covert structural features.

Reconfigurable fiber-to-waveguide coupling module enabled by phase-change material incorporated switchable directional couplers.

In silicon photonics, grating-assisted fiber-to-waveguide couplers provide out-of-plane coupling to facilitate wafer-level testing; however, their limited bandwidth and efficiency restrict their use in broadband applications. Alternatively, end-fire couplers overcome these constraints but require a dicing process prior usage, which makes them unsuitable for wafer-level testing. To address this trade-off, a reconfigurable fiber-to-waveguide coupling module is proposed and designed to allow for both grating-assisted and end-fire coupling in the same photonic circuit. The proposed module deploys a switchable directional coupler incorporating a thin layer of phase-change material, whose state is initially amorphous to render the coupler activated and hence facilitate grating-assisted coupling for wafer-level testing. The state can be altered into crystalline through a low-temperature annealing process to deactivate the directional coupler, thus facilitating broadband chip-level coupling through end-fire couplers. All the components encompassing conjoined switchable directional couplers as well as the grating and end-fire couplers were individually designed through rigorous simulations. They were subsequently assembled to establish the proposed reconfigurable coupling module, which was simulated and analyzed to validate the selective coupling operation. The proposed module gives rise to a low excess loss below 1.2 dB and a high extinction ratio over 13 dB throughout the C-band, when operating either under grating-assisted or end-fire input. The proposed reconfigurable coupling module is anticipated to be a practical solution for flexibly expediting the inspection of integrated photonic circuits on a wafer scale.

Flat optical phased array receiver incorporating an on-chip metalens concentrator.

We propose and design a flat optical phased array (OPA) receiver that consists of a grating antenna, a free-propagation region (FPR) incorporating an on-chip metalens concentrator (OCMC), and an output port of a tapered waveguide. By concatenating the OCMC-integrated FPR with the antenna, the proposed OPA allows light coupled at a slanted ψ angle to be conveyed to the output, thereby resolving the challenges of phase-controlled light detection. To impose a space-dependent phase on the incident light from the antenna, the OCMC is constructed by laterally arranging subwavelength slot meta-atoms with varying slot lengths, which are created in the core layer of a slab and uniformly quantized at 16 phase levels. Hence, without the aid of phase modulators, the light beam emerging from the grating antenna can be focused on the output port through angle-tolerant coupling along the lateral direction. The miniaturized OCMC was confirmed to play a pivotal role in achieving enhanced in-plane coupling efficiency over the field of view.

Fast-running beamforming algorithm for optical phased array beam scanners comprised of polymeric waveguide devices.

The phase error imposed in optical phased arrays (OPAs) for beam scanning LiDAR is unavoidable due to minute dimensional fluctuations that occur during the waveguide manufacturing process. To compensate for the phase error, in this study, a fast-running beamforming algorithm is developed based on the rotating element vector method. The proposed algorithm is highly suitable for OPA devices comprised of polymer waveguides, where thermal crosstalk between phase modulators is suppressed effectively, allowing for each phase modulator to be controlled independently. The beamforming speed is determined by the number of phase adjustments. Hence, by using the least square approximation for a 32-channel polymer waveguide OPA device the number of phase adjustments needed to complete beamforming was reduced and the beamforming time was shortened to 16 seconds.

The prevalence and correlates of depression in Korean adults with rheumatoid arthritis: Results from the Korea National Health and Nutrition Examination Surveys.

PURPOSE: This study aimed to investigate the prevalence and correlates of depression in Korean patients with rheumatoid arthritis (RA). METHODS: We analyzed the data of the Korean National Health and Nutrition Examination Survey (KNHANES). The sociodemographic, clinical, and psychiatric variables were compared between the RA group (n = 277) and the gender- and age-matched non-RA group (n = 1068). Participants in the RA group who had a Patient Health Questionnaire-9 (PHQ-9) score of 10 or more were sub-categorized as the depression group (n = 52), and the prevalence of depression with RA was determined. Complex samples logistic regression analysis was performed to clarify the associated factors for depression in patients with RA. RESULTS: The prevalence of depression in patients with RA was 17.4%. The RA group experienced more pain, restrictions on usual activities, and stress in their daily lives. RA patients with 3 or more comorbid diseases, extreme pain, problems in usual activities, and moderate to severe perceived stress were more likely to develop depression. Female gender and low income were also associated factors to consider. CONCLUSION: Depression is significantly prevalent in Korean RA patients. Along with managing pain and daily life functions, interventions to reduce perceived stress are needed for comprehensive RA management.

Efficient All-Dielectric Diatomic Metasurface for Linear Polarization Generation and 1-Bit Phase Control.

Optical metasurface has exhibited unprecedented capabilities in the regulation of light properties at a subwavelength scale. In particular, a multifunctional polarization metasurface making use of light polarization to integrate distinct functionalities on a single platform can be greatly helpful in the miniaturization of photonic systems and has become a hot research topic in recent years. Here, we propose and demonstrate an efficient all-dielectric diatomic metasurface, the unit cell of which is composed of a pair of a-Si:H-based nanodisks and nanopillars that play the roles as polarization-maintaining and polarization-converting meta-atoms, respectively. Through rigorous theoretical analyses and numerical simulations, we show that a properly designed diatomic metasurface can work as a nanoscale linear polarizer for generating linearly polarized light with a controllable polarization angle and superior performances including a maximum transmission efficiency of 96.2% and an extinction ratio of 32.8 dB at an operation wavelength of 690 nm. Three metasurface samples are fabricated and experimentally characterized to verify our claims and their potential applications. Furthermore, unlike previously reported dielectric diatomic metasurfaces which merely manipulate the polarization state, the proposed diatomic metasurface can be easily modified to empower 1-bit phase modulation without altering the polarization angle and sacrificing the transmission efficiency. This salient feature further leads to the demonstration of a metasurface beam splitter that can be equivalently seen as the integration of a nonpolarizing beam splitter and a linear polarizer, which has never been reported before. We envision that various metadevices equipping with distinct wavefront shaping functionalities can be realized by further optimizing the diatomic metasurface to achieve an entire 2π phase control.

Alteration of Pituitary Tumor Transforming Gene 1 by MicroRNA-186 and 655 Regulates Invasion Ability of Human Oral Squamous Cell Carcinoma.

BACKGROUND: Pituitary tumor-transforming gene 1 (PTTG1) was recently shown to be involved in the progression as well as the metastasis of cancers. However, their expression and function in the invasion of oral squamous cell carcinoma (SCC) remain unclear. METHODS: The expressions of PTTG1 and PTTG1-targeted miRNA in oral SCC cell lines and their invasion capability depended on PTTG1 expression were analyzed by quantitative RT-PCR, Western blots, the transwell insert system and Zymography. RESULTS: Invasion abilities were decreased in oral SCC cells treated with siRNA-PTTG1. When PTTG1 were downregulated in oral SCC cells treated with microRNA-186 and -655 inhibited their invasion abilities via MMP-9 activity. CONCLUSIONS: These results indicate that alteration of expression of PTTG1 in oral SCC cells by newly identified microRNA-186 and -655 can regulate invasion activity. Therefore, these data offer new insights into further understanding PTTG1 function in oral SCC and should provide new strategies for diagnostic markers for oral SCC.