Mcgrathadair6960

We theoretically investigate the single photon scattering properties in a waveguide chirally coupling to a giant atom. The single photon transmission spectrum depends on the direction of the single photon incident when the energy loss of the giant atom can not be neglected. The difference between the transmission probabilities corresponding to opposite transport direction ΔT is calculated. It shows that both of the position and width of the ΔT are dependent on the size of the giant atom. Furthermore, the position of the maximum ΔT and the frequency width of ΔT can be modulated by a classical laser beam. Our results will be beneficial to control single photons in quantum devices design involving giant atoms.We designed and optimized ultra-thin single junction InAlGaAs photonic power converters (PPC) with integrated back reflectors (BR) for operation at the telecommunications wavelength of 1310 nm and numerically studied the light trapping capability of three BR types planar, cubic nano-textured, and pyramidal nano-textured. The PPC and BR geometries were optimized to absorb a fixed percentage of the incident light at the target wavelength by coupling finite difference time-domain (FDTD) calculations with a particle swarm optimization. With 90% absorptance, opto-electrical simulations revealed that ultra-thin PPCs with 5.6- to 8.4-fold thinner absorber layers can have open circuit voltages (Voc) that are 9-12% larger and power conversion efficiencies (PCE) that are 9-10% (relative) larger than conventional thick PPCs. Compared to a thick PPC with 98% absorptance, these ultra-thin designs reduce the absorber layer thickness by 9.5-14.2 times while improving the Voc by 12-14% and resulting in a relative PCE enhancement of 3-4%. Of the studied BR designs, pyramidal BRs exhibit the highest performance for ultra-thin designs, reaching an efficiency of 43.2% with 90% absorptance, demonstrating the superior light trapping capability relative to planar and cubic nano-textured BRs.Terahertz (THz) imaging has been regarded as cutting-edge technology in a wide range of applications due to its ability to penetrate through opaque materials, non-invasive nature, and its increased bandwidth capacity. Recently, THz imaging has been extensively researched in security, driver assistance technology, non-destructive testing, and medical applications. The objective of this review is to summarize the selection criteria for current state-of-the-art THz image reconstruction algorithms developed for short-range imaging applications over the last two decades. Moreover, we summarize the selected algorithms' performance and their implementation process. This study provides an in-depth understanding of the fundamentals of image reconstruction algorithms related to THz short-range imaging and future aspects of algorithm processing and selection.We show scanning dynamic light scattering optical coherence tomography (OCT) omnidirectional flow measurements. Our method improves the velocity measurement limit over conventional correlation-based or phase-resolved Doppler OCT by more than a factor of 2. Our technique is applicable without a-priori knowledge of the flow geometry as our method works both for non-zero Doppler angle and non-ideal scan alignment. In addition, the method improves the particle diffusion coefficient estimation for particles under flow.The essence of stock market forecasting is to reveal the intrinsic operation rules of stock market, however it is a terribly arduous challenge for investors. The application of nanophotonic technology in the intelligence field provides a new approach for stock market forecasting with its unique advantages. In this work, a novel nanophotonic reservoir computing (RC) system based on silicon optomechanical oscillators (OMO) with photonic crystal (PhC) cavities for stock market forecasting is implemented. The long-term closing prices of four representative stock indexes are accurately forecast with small prediction errors, and the forecasting results with distinct characteristics are exhibited in the mature stock market and emerging stock market separately. Our work offers solutions and suggestions for surmounting the concept drift problem in stock market environment. The comprehensive influence of RC parameters on forecasting performance are displayed via the mapping diagrams, while some intriguing results indicate that the mature stock markets are more sensitive to the variation of RC parameters than the emerging stock markets. Furthermore, the direction trend forecasting results illustrate that our system has certain direction forecasting ability. Additionally, the stock forecasting problem with short listing time and few data in the stock market is solved through transfer learning (TL) in stock sector. The generalization ability (GA) of our nanophotonic reservoir computing system is also verified via four stocks in the same region and industry. Therefore, our work contributes to a novel RC model for stock market forecasting in the nanophotonic field, and provides a new prototype system for more applications in the intelligent information processing field.We present a multitasking tailored device (MTD) based on phase change material vanadium dioxide (VO2) and photoconductive semiconductor (PS) in the terahertz (THz) regime, thereby manipulating the interaction between electromagnetic waves and matter. By altering the control multitasking device, its room temperature, or pump illumination, we switch the function of absorption or polarization conversion (PC) on and off, and realize the tuning of absorptivity and polarization conversion rate (PCR). Meanwhile, the construction of cylindrical air columns (CACs) in the dielectric provides an effective channel to broaden the absorption bandwidth. For the MTD to behave as a polarization converter with VO2 pattern in the insulating phase (IP), exciting the PS integrated to the proposed device via an optical pump beam, the PCR at 0.82-1.6 THz can be modulated continuously from over 90% to perfectly near zero. When the PS conductivity is fixed at 3×104 S/m and VO2 is in the metal phase (MP) simultaneously, the MTD switched to an absorber exhibits ultra-broadband absorption with the absorptivity over 90% at 0.68-1.6 THz. By varying the optical pump power and thermally controlling the conductivity of VO2, at 0.68-1.6 THz, the absorbance of such a MTD can be successively tuned from higher than 90% to near null. Additionally, the influences of the polarization angle and incident angle on the proposed MTD are discussed. The designed MTD can effectively promote the electromagnetic reconfigurable functionalities of the present multitasking devices, which may find attractive applications for THz modulators, stealth technology, communication system, and so on.In this work, we have reported a vertical CsPbBr3/ZnO heterojunction photodetector for photo-sensing lights from UV to visible band. The ZnO thin film is deposited on the c-sapphire substrate through a molecular beam epitaxy (MBE) technique, and then the CsPbBr3 thin film is synthesized on the as-prepared ZnO film layer by using a solution processing method. The as-prepared CsPbBr3/ZnO heterostructure presents type-II energy band structure induced by the energy band offset effect, which can promote the separation and extraction efficiencies of the photo-generated electron-hole pairs. Compared with the CsPbBr3 based metal-semiconductor-metal (MSM) structure photodetector, the heterojunction photodetector presents higher responsivity and detectivity of 630 µA/W and 7 × 109 Jones. While compared with the ZnO based MSM structure photodetector, the heterojunction device reveals much faster response speeds of 61 µs (rise time) and 1.4 ms (decay time). These findings demonstrate that the CsPbBr3/ZnO heterojunction photodetector is promising for constructing next generation perovskite based optoelectronic devices.Quantum well intermixing (QWI) on a III-V-on-insulator (III-V-OI) substrate is presented for active-passive integration. Shallow implantation at a high temperature, which is essential for QWI on a III-V-OI substrate, is accomplished by phosphorus molecule ion implantation. As a result, the bandgap wavelength of multi-quantum wells (MQWs) on a III-V-OI substrate is successfully tuned by approximately 80 nm, enabling the monolithic integration of electro-absorption modulators and waveguide photodetectors using a lateral p-i-n junction formed along the InP/MQW/InP rib waveguide. Owing to the III-V-OI structure and the rib waveguide structure, the parasitic capacitance per unit length can be reduced to 0.11 fF/µm, which is suitable for high-speed and low-power modulators and photodetectors. The presented QWI can extend the possibility of a III-V complementary metal-oxide-semiconductor (CMOS) photonics platform for large-scale photonic integrated circuits.Vortex beam carrying orbital angular momentum (OAM) is disturbed by oceanic turbulence (OT) when propagating in underwater wireless optical communication (UWOC) system. Adaptive optics (AO) is a powerful technique used to compensate for distortion and improve the performance of the UWOC system. In this work, we propose a diffractive deep neural network (DDNN) based AO scheme to compensate for the distortion caused by OT, where the DDNN is trained to obtain the mapping between the distortion intensity distribution of the vortex beam and its corresponding phase screen representing OT. selleck chemicals In the experiment, the distorted vortex beam is input into the DDNN model where the diffractive layers are solidified and fabricated, and the intensity distribution of the modulated light field of the vortex beam can be recorded. The experiment results show that the proposed scheme can extract quickly the characteristics of the intensity pattern of the distorted vortex beam, and the predicted compensation phase screen can correct the distortion caused by OT in time. The mode purity of the compensated vortex beam is significantly improved, even with a strong OT. Our scheme may provide a new avenue for AO techniques, and is expected to promote the communication quality of UWOC system immediately.We report a whispering gallery mode (WGM)-based fiber optofluidic laser (FOFL), in which rhodamine B (RhB) in an aqueous surfactant solution of sodium dodecylbenzene sulfonate (SDBS) is used as the laser gain medium. Here, the role of SDBS is to scatter the RhB dye molecules to effectively prevent its self-association in the aqueous solution. Therefore, the fluorescence quantum yield of the used RhB dye is improved due to the enhanced solubilization, which results in a low lasing threshold of ∼2.2 µJ/mm2 when the concentration of SDBS aqueous solution reaches up to 20 mM, on par with or even better than most of the optofluidic dye lasers using RhB as the gain medium in an organic solution. We then establish a model of solubilization capacity of SDBS micelles, which successfully addresses the mechanisms of dye-surfactant interactions in the proposed FOFL system. We further apply this FOFL platform to the case of concentration sensing of the used SDBS, which exhibits a 2-order-of-magnitude improvement in sensitivity compared to the fluorescence measurement due to the signal amplification inherent to the lasing process. The proposed FOFL platform in combination with surfactant solubilization gain medium in an aqueous solution promises to enable chip-scale coherent light sources for various environmental and bio-chemical sensing applications.