Low-power signals experience a 03dB and 1dB boost in performance metrics. Compared to 3D orthogonal frequency-division multiplexing (3D-OFDM), the proposed 3D non-orthogonal multiple access (3D-NOMA) method offers the potential for a larger user base without apparent performance compromises. 3D-NOMA's exceptional performance makes it a promising approach for future optical access systems.

Multi-plane reconstruction is paramount for the development of a functioning holographic three-dimensional (3D) display. In conventional multi-plane Gerchberg-Saxton (GS) algorithms, inter-plane crosstalk is a significant concern. This arises from the omission of the interference from other planes during the amplitude replacement procedure at each object plane. Utilizing time-multiplexing stochastic gradient descent (TM-SGD), this paper proposes an optimization algorithm to address multi-plane reconstruction crosstalk. The global optimization feature of stochastic gradient descent (SGD) was initially used to address the issue of inter-plane crosstalk. However, the crosstalk optimization's impact weakens with a rising number of object planes, due to an imbalance in the quantity of input and output data. Subsequently, we integrated a time-multiplexing technique into the iterative and reconstructive process of multi-plane SGD to bolster the informational content of the input. Sub-holograms, produced via multi-loop iteration in TM-SGD, are sequentially applied to the spatial light modulator (SLM). The optimization criteria governing the interplay between holograms and object planes evolve from a one-to-many to a many-to-many configuration, leading to a more refined optimization of inter-plane crosstalk. During the persistence of sight, multiple sub-holograms collaboratively reconstruct the crosstalk-free multi-plane images. Employing simulation and experimentation, we confirmed that TM-SGD successfully reduces inter-plane crosstalk and yields higher image quality.

We present a continuous-wave (CW) coherent detection lidar (CDL) system for identifying micro-Doppler (propeller) features and capturing raster-scanned images of small unmanned aerial systems/vehicles (UAS/UAVs). A narrow linewidth 1550nm CW laser is integral to the system's design, which also takes advantage of the proven and low-cost fiber-optic components from telecommunications. Employing lidar technology, the characteristic pulsating motions of drone propellers were identified from afar, up to 500 meters, regardless of the beam geometry used – either collimated or focused. Furthermore, two-dimensional images of airborne UAVs, located up to a maximum range of 70 meters, were captured by raster scanning a focused CDL beam with a galvo-resonant mirror beamscanner. Raster-scanned images provide information about the target's radial velocity and the lidar return signal's amplitude, all via the details within each pixel. Raster-scan images, obtained at a speed of up to five frames per second, facilitate the recognition of varied UAV types based on their silhouettes and enable the identification of attached payloads. The anti-drone lidar, with realistic improvements, presents an enticing alternative to the expensive EO/IR and active SWIR cameras often employed within counter-unmanned aerial vehicle systems.

A continuous-variable quantum key distribution (CV-QKD) system relies on the data acquisition process to generate secure secret keys. Common data acquisition methods rely on the presumption of unchanging channel transmittance. The transmittance of the free-space CV-QKD channel is inconsistent during the transmission of quantum signals; therefore, the existing methods are inappropriate for this situation. This paper introduces a data acquisition method utilizing a dual analog-to-digital converter (ADC). Employing a dynamic delay module (DDM) and two ADCs, synchronized to the pulse repetition rate, this high-precision data acquisition system compensates for transmittance variations through a simple division of the ADC data streams. Simulation and experimental results, validated through proof-of-principle trials, highlight the effectiveness of the scheme for free-space channels. High-precision data acquisition is achievable under conditions of fluctuating channel transmittance and very low signal-to-noise ratios (SNR). Finally, we provide the direct application scenarios of the proposed framework within free-space CV-QKD systems and verify their practicality. This approach holds substantial importance for enabling both the experimental implementation and practical application of free-space CV-QKD systems.

The application of sub-100 femtosecond pulses is noteworthy for its ability to advance the quality and precision of femtosecond laser microfabrication processes. While utilizing such lasers at pulse energies frequently employed in laser processing, the nonlinear propagation within the air is known to alter the beam's temporal and spatial intensity distribution. Predicting the final shape of the processed craters in materials vaporized by these lasers has been problematic due to this distortion. Quantitative prediction of ablation crater shape was achieved in this study via the utilization of nonlinear propagation simulations. Subsequent investigations corroborated that the ablation crater diameters calculated by our method exhibited excellent quantitative alignment with experimental findings for several metals, across a two-orders-of-magnitude range in pulse energy. A substantial quantitative correlation was identified between the simulated central fluence and the resulting ablation depth. Improved controllability of laser processing using sub-100 fs pulses is anticipated with these methods, enabling broader practical application across varying pulse energies, including situations characterized by nonlinear pulse propagation.

Data-intensive technologies currently emerging require low-loss, short-range interconnections, as opposed to existing interconnects, which suffer from high losses and low aggregate data throughput, the cause of which is the absence of effective interfaces. A newly developed 22-Gbit/s terahertz fiber link utilizes a tapered silicon interface as a coupler for the interconnection of a dielectric waveguide and a hollow core fiber. We examined the core optical characteristics of hollow-core fibers, specifically focusing on fibers possessing core diameters of 0.7 millimeters and 1 millimeter. Within the 0.3 THz frequency range, a 10-centimeter fiber achieved a 60% coupling efficiency and a 3-dB bandwidth of 150 GHz.

From the perspective of coherence theory for non-stationary optical fields, we introduce a new type of partially coherent pulse source with the multi-cosine-Gaussian correlated Schell-model (MCGCSM) structure, and subsequently deduce the analytic expression for the temporal mutual coherence function (TMCF) of such an MCGCSM pulse beam during propagation through dispersive media. A numerical investigation of the temporally averaged intensity (TAI) and the temporal coherence degree (TDOC) of MCGCSM pulse beams propagating through dispersive media is undertaken. Selleckchem PLX5622 Analysis of our results demonstrates that varying source parameters influences the progression of pulse beams through distance, transforming them from a single initial beam into either multiple subpulses or a flat-topped TAI profile. Selleckchem PLX5622 Additionally, a chirp coefficient falling below zero results in MCGCSM pulse beams traversing dispersive media displaying the hallmarks of two concurrent self-focusing phenomena. A physical account is provided for the occurrence of two distinct self-focusing processes. Laser micromachining, material processing, and multiple pulse shaping procedures are all made possible by the pulse beam applications detailed in this paper.

The interface between a metallic film and a distributed Bragg reflector is where electromagnetic resonance effects, creating Tamm plasmon polaritons (TPPs), occur. While surface plasmon polaritons (SPPs) exhibit different characteristics, TPPs showcase a unique blend of cavity mode properties and surface plasmon behavior. This paper focuses on a careful study of the propagation characteristics exhibited by TPPs. Nanoantenna couplers are instrumental in the directional propagation of polarization-controlled TPP waves. Nanoantenna couplers, when combined with Fresnel zone plates, demonstrate asymmetric double focusing of TPP waves. Selleckchem PLX5622 In addition, radial unidirectional TPP wave coupling is attainable with nanoantenna couplers arranged in a circular or spiral pattern. This arrangement's focusing ability outperforms a single circular or spiral groove, boosting the electric field intensity at the focal point to four times the level. Compared to SPPs, TPPs display a superior excitation efficiency and a lower propagation loss. A numerical investigation reveals TPP waves' significant potential for integrated photonics and on-chip device applications.

By combining time-delay-integration sensors and coded exposure, we create a compressed spatio-temporal imaging framework that allows for both high frame rates and continuous streaming concurrently. Without the inclusion of extra optical coding elements and their subsequent calibration, this electronic-domain modulation permits a more compact and resilient hardware structure in comparison to currently employed imaging modalities. Benefiting from the intra-line charge transfer methodology, a super-resolution effect is obtained in both the temporal and spatial domains, ultimately increasing the frame rate to millions of frames per second. The forward model, with adjustable coefficients after training, and its two associated reconstruction methods, provide flexible post-interpretation of voxel data. By employing both numerical simulations and proof-of-concept experiments, the proposed framework's effectiveness is definitively shown. The proposed system's efficacy arises from its extended temporal window and customizable voxel analysis after interpretation, making it suitable for imaging random, non-repetitive, or long-term events.

This proposal details a twelve-core, five-mode fiber with a trench-assisted structure, which combines a low refractive index circle and a high refractive index ring (LCHR). Employing a triangular lattice arrangement, the 12-core fiber operates.