As an artificial two-dimensional (2D) metamaterial, metasurface has been widely studied for its ability to regulate electromagnetic waves through simple structures. However, traditional metasurfaces make it difficult to modulate different polarizations by a single device, let alone the reasonable allocation of energy to multiplexed polarizations, which is not suitable for comprehensive applications in multifunctional integrated system. Here, a full polarization multiplexing scheme and power-target-field-based addition theory for multiple beams, and an interference reduction scheme are theoretically proposed and experimentally achieved using anisotropic metasurfaces. The full polarization multiplexing scheme achieves different linearly polarized and circularly polarized beams using the same feed and tensor units with a simple design for the first time. The proposed addition theory modifies the existing scheme to achieve performance improvement and accurate energy allocation for multiple beams. The interference reduction scheme can control the propagation orientation and initial position of multiple beams, and finally achieve multi-dimensional control. All methods are verified by achieving 2D Airy beams, and the relationship between modulation function and the surface impedance that reflects material characteristics is studied. The anisotropic metasurfaces provide multiplexing functions using multiple beams with orthogonal polarization states and controllable power levels, which represents a simple and effective transmitting end for multi-functional systems and multiple targets in wireless transfer systems.

Conventional single-pixel imaging (SPI) typically relies on expensive dynamic projectors or bulky moving parts, making its cost-effective implementation difficult in non-visible wavelength ranges. In this paper, we propose a compact, low-cost, and entirely solid-state single-static-pattern SPI (SSPI) system for moving objects. Our system employs a wavelength-independent metal-plate mask with microholes to generate illumination patterns, eliminating the need for dynamic projection devices. We carefully model the unique constraints of this configuration, such as image resolution and background reflection, and propose effective mitigation methods. Experimental demonstrations in the visible range confirm the effectiveness of the system. We also verify the mask's functionality in the short-wave infrared (SWIR) range, highlighting its potential for non-visible applications.

What is believed to be a new phenomenon - plasma-based thermally-induced optical reflection of sound (P-THORS) - overcomes the limitations of traditional THORS (e.g. need for line-of-sight, concentration dependence, and variations in efficiency at distance) by using a laser to generate a shaped plasma for the formation of highly-efficient, variable geometry, free-space acoustic reflector/barrier. These reflectors allow for the focusing and steering of acoustic waves without the need of a continuous barrier or engineered materials. This work demonstrates for the first time the generation of P-THORS barriers with highly efficient reflection efficiencies, exceeding those of traditional THORS barrier (i.e. > 70%) as well as the ability to transiently shape the barrier into various geometries to steer the acoustic wave to specific locations. P-THORS barriers are shown to reflect near 100% of incident ultrasonic signals and maintain that reflectivity for 5 ms post-plasma formation. Furthermore, by shaping the plasma it was possible to selectively direct the ultrasonic and/or acoustic waves to a desired location with efficiencies of 30% or greater, depending on the geometry of the shaped plasma.

A high-speed phase calibration method for large-scale silicon-based optical phased arrays (OPAs) is proposed, integrating the Hadamard parallel gradient descent (HPGD) algorithm and a dedicated hardware architecture. Deterministic, orthogonal Hadamard matrices generate perturbation sequences, enabling efficient optimization. The architecture consists of an FPGA, a DSP, and a high-speed avalanche photodiode (APD), employing the APD to acquire objective functions. Simulations show that, compared with the stochastic parallel gradient descent algorithm, HPGD reduces convergence iterations for a 512-element OPA from 4929 to 2285, and a variant with adaptive gain (adaHPGD) further reduces iterations to 1480 (70.0% reduction). For OPAs with 1024 to 4096 elements, HPGD reduces iterations by 31.8% to 41.3%. Experimentally, on a 512-element OPA, each iteration takes 6.7 ms, with a convergence time of 12.8 s. After calibration, the beam achieves a peak sidelobe ratio of 12.93 dB and a full width at half maximum of 0.110°, matching simulations.

Frequency-scanning nonlinearity fundamentally limits the ranging precision of frequency-scanning interferometry (FSI) systems based on external cavity diode lasers (ECDLs). To address this limitation, a frequency scanning nonlinearity suppression method based on a rate-dependent asymmetric Prandtl-Ishlinskii (RA-PI) model is proposed. By employing, for the first time, a phenomenological modeling approach, the rate-dependent and asymmetric nonlinear optical frequency response of the ECDL is accurately characterized. An inverse RA-PI model is derived and implemented as a feedforward compensator to linearize the frequency scanning. Experimental results show that the frequency-scanning linearity is improved by approximately one order of magnitude. Consequently, the maximum standard deviation of absolute distance measurements is reduced from 58.25 μm to 9.79 μm, and the maximum relative displacement deviation decreases from 42.97 μm to 11.56 μm. Furthermore, the velocity measurement precision for dynamic targets is improved by a factor of 2.61 to 5.75.

High speed and high saturation power germanium-silicon (Ge-Si) photodetectors (PDs) are highly desirable for microwave photonic links. However, the impact of series resistance on their performance remains poorly understood. In this work, the series resistance is engineered by optimizing the via-opening geometry while keeping the vertical PIN junction unchanged. A set of waveguide-integrated Ge-Si PDs with identical active regions but different via geometries is systematically characterized. The series resistance is extracted through equivalent-circuit fitting of the measured small-signal frequency responses, and the saturation behavior is quantified using photocurrent-optical power characteristics. Devices with reduced series resistance consistently exhibit both enhanced 3 dB bandwidth and improved saturation output capability. These improvements are attributed to the dual role of lower series resistance, which alleviates RC limited bandwidth and suppresses current-induced voltage drop, thereby maintaining the effective junction reverse bias and delaying output compression. The results provide a process compatible strategy for realizing high speed and high power Ge-Si PDs.