Lidar based on the optical phased array (OPA) and frequency-modulated continuous wave (FMCW) technology stands out in automotive applications due to its all-solid-state design, high reliability, and remarkable resistance to interference. However, while FMCW coherent detection enhances the interference resistance capabilities, it concurrently results in a significant increase in depth computation, becoming a primary constraint for improving point cloud density in such perception systems. To address this challenge, this study introduces a lidar solution leveraging the flexible scanning characteristics of OPA. The proposed system categorizes target types within the scene based on RGB images. Subsequently, it performs scans with varying angular resolutions depending on the importance of the targets. Experimental results demonstrate that, compared to traditional scanning methods, the target-adaptive method based on semantic segmentation reduces the number of points to about one-quarter while maintaining the resolution of the primary target area. Conversely, with a similar number of points, the proposed approach increases the point cloud density of the primary target area by about four times.

In this review paper, we discuss the properties and applications of photonic computing and analog signal processing. Photonic computational circuits have large operation bandwidth, low power consumption, and fine frequency control, enabling a wide range of application-specific computational techniques that are impossible to implement using traditional electrical and digital hardware alone. These advantages are illustrated in the elegant implementation of optical steganography, the real-time blind separation of signals in the same bandwidth, and the efficient acceleration of artificial neural network inference. The working principles and use of photonic circuits for analog signal processing and neuromorphic computing are reviewed and notable demonstrated applications are highlighted.

AlGaN-based light-emitting diodes (LEDs) on offcut substrates enhance radiative emission via forming carrier localization centers in multiple quantum wells (MQWs). This study introduces the carrier transport barrier concept, accessing its impact on the quantum efficiency of LEDs grown on different offcut sapphire substrates. A significantly enhanced internal quantum efficiency (IQE) of 83.1% is obtained from MQWs on the 1° offcut sapphire, almost twice that of the controlled 0.2° offcut sample. Yet, 1° offcut LEDs have higher turn-on voltage and weaker electroluminescence than 0.2° ones. Theoretical calculations demonstrate the existence of a potential barrier on the current path around the step-induced Ga-rich stripes. Ga-rich stripes reduce the turn-on voltage but restrict sufficient driving current, impacting LED performance.

Organic–inorganic hybrid perovskite formamidinium lead bromide nanosheet (FAPbBr₃ NS) is regarded as a superior substance used to construct optoelectronic devices. However, its uncontrollable stability seriously affects its application in the field of photodetectors. In this paper, FAPbBr₃ is combined with cadmium sulfide nanobelt (CdS NB) to construct a hybrid device that greatly improves the stability and performance of the photodetector. The response of the FAPbBr₃ NS/CdS NB detector under 490 nm light illumination reaches 5712 A/W, while the response of the FAPbBr₃ photodetector under equivalent conditions is only 25.45 A/W. The photocurrent of the FAPbBr₃ NS/CdS NB photodetector is nearly 80.25% of the initial device after exposure to air for 60 days. The difference in electric field distribution between the single material device and the composite device is simulated by the finite-difference time-domain method. It shows the advantages of composite devices in photoconductive gain and directly promotes the hybrid device performance. This paper presents a new possibility for high stability, fast response photodetectors.

In this paper, we demonstrate nBn InAs/InAsSb type II superlattice (T2SL) photodetectors with AlAsSb as the barrier that targets mid-wavelength infrared (MWIR) detection. To improve operating temperature and suppress dark current, a specific Sb soaking technique was employed to improve the interface abruptness of the superlattice with device passivation using a SiO2 layer. These result in ultralow dark current density of 6.28×10-6A/cm2 and 0.31A/cm2 under -600mV at 97 K and 297 K, respectively, which is lower than most reported InAs/InAsSb-based MWIR photodetectors. Corresponding resistance area product values of 3.20×104Ω·cm2 and 1.32Ω·cm2 were obtained at 97 K and 297 K. A peak responsivity of 0.39 A/W with a cutoff wavelength around 5.5 µm and a peak detectivity of 2.1×109cm·Hz1/2/W were obtained at a high operating temperature up to 237 K.

Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability. Over the past several years, benefitting from the sustainable innovations in laser technology and the significant progress in materials technology, megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices. Here, we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode, including the mechanism, system architecture, critical technology, and experimental demonstration of the proposed high-power photonic microwave sources. The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.

The fabrication of different perovskite materials with superior properties into lateral heterostructures can greatly improve device performance and polarization sensitivity. However, the sensitivity of perovskites to solvents and environmental factors makes the fabrication of lateral heterojunctions difficult. Here, we realize high-quality perovskite microwire crystal heterojunction arrays using regioselective ion exchange. Photodetectors with responsivity and detectivity up to 748AW-1 and 8.2×1012 Jones are fabricated. The photodetector exhibits responsivity as high as 13.5AW-1 at 0 V bias. In addition, the device exhibits ultra-high polarization sensitivity with a dichroic ratio of 5.6, and 81% of its performance was maintained after 144 days of exposure to air.

In this work, a Si/MoS2 heterojunction photodetector enhanced by hot electron injection through Fano resonance is developed. By preparing Au oligomers using capillary-assisted particle assembly (CAPA) on the silicon substrate with a nanohole array and covering few-layer MoS2 with Au electrodes on top of the oligomer structures, the Fano resonance couples with a Si/MoS2 heterojunction. With on-resonance excitation, Fano resonance generated many hot electrons on the surface of oligomers, and the hot electrons were injected into MoS2, providing an increased current in the photodetector under a bias voltage. The photodetectors exhibited a broadband photoresponse ranging from 450 to 1064 nm, and a large responsivity up to 52 A/W at a wavelength of 785 nm under a bias voltage of 3 V. The demonstrated Fano resonance-enhanced Si/MoS2 heterojunction photodetector provides a strategy to improve the photoresponsivity of two-dimensional materials-based photodetectors for optoelectronic applications in the field of visible and near-infrared detection.

Superconducting nanowires enable the operation of outstanding single-photon detectors, which are required particularly for quantum information and weak-light measurement applications. However, the trade-off between detection speed and efficiency, which is related to the filling factors of superconducting nanowires, is still a challenge. Here, we propose a fast, efficient single-photon detector fabricated by integrating ultralow-filling-factor meandered superconducting nanowires atop a photonic crystal (PhC) resonator. This unique structure enables a fast photon response due to the low kinetic inductance of the short nanowires and ensures efficient photon absorption due to the resonant effect of the PhC structure. The proposed detector has a filling factor of only ∼12% while maintaining a high maximum absorption in our simulation of 90%. The fabricated device exhibits a maximum system detection efficiency of 60%, a maximum count rate of ∼80MHz, and a recovery time of only ∼12ns, which is three times faster than that of the conventional meandered structure at the same sensing diameter (18 μm). This work helps advance the movement toward high-efficiency, high-speed single-photon detectors and promotes their future application in quantum communication and imaging.

Top-illuminated structure facilitates the integration of organic photodetectors (OPDs) into high-resolution flexible wearable light detection systems by allowing the OPDs to be deposited on the bottom readout circuit. However, constructing this structure poses a challenge as it demands metallic electrodes with both high optical transparency and high electrical conductivity. But to achieve practical sheet resistances, most semitransparent metallic electrodes tend to reflect a large portion of incident light instead of allowing it to be absorbed by the photoactive layer of the OPDs. This, in turn, results in reduced photocurrent generation. To address this issue, a semiconducting germanium (Ge) film is introduced into a sliver (Ag) film, effectively reducing its reflectivity by lessening scattering. The Ge film also changes how the Ag film grows, further reducing its absorption by lowering the critical thickness needed for forming a continuous film. This approach yields a 10 nm metallic electrode with a transmittance of 70%, a reflectivity of 12%, and a sheet resistance of 35.5 Ω/□. Using this metallic electrode, flexible OPDs exhibit a high photo-to-dark current ratio of 2.9×104 and improved mechanical properties. This finding highlights the benefits of the top-illuminated structure, which effectively reduces losses caused by waveguided modes of the incident light.