As materials science, nanotechnology, and energy conversion technologies continue to advance, renewable energy technologies continue to evolve. Photovoltaic power generation has become one of the most widely used renewable energy generation technologies. However, photovoltaic cells rely on sunlight to generate electricity and cannot work under poor light intensity or dark conditions. As a new type of energy conversion technology, thermoradiative photovoltaics can generate electricity in the absence of light, and the working principle of the device is similar to that of solar cells working in reverse, providing another way for energy production. In the future, thermoradiative photovoltaics may become one of the important ways of power generation, with broad application prospects and significant development potential. This paper reviews the research progress of domestic and foreign scholars in thermoradiative photovoltaics, summarizes, and analyzes future prospects and outlooks.

A single-station real-time multi-target 3D coordinate measurement system is proposed to address the challenges in traditional multi-base station positioning systems that rely on multi-source observation intersection mechanisms. Such systems are often hindered by occlusions in complex environments and face difficulties in station layout adjustments. Achieving single-station real-time multi-target 3D sensing and measurement requires a measurement module with parallel range angle sensing capability to decouple the strong correlation between range and angle measurements, thus meeting the demands of real-time automatic multi-target measurement. This paper presents a novel method combining ultra-wideband ranging and rotational laser scanning for angle measurement. A comprehensive calibration model and measurement model for the range angle fusion system are established, and cooperative targets are designed with an analysis of the effect of target decentering errors. Additionally, a compensation method for systematic errors in the UWB ranging system is studied. Finally, a prototype system is developed for feasibility verification. Experimental results demonstrate that the proposed single-station measurement system achieves an average point error of less than 30 mm, representing nearly a 70% reduction in error compared to traditional UWB multi-target positioning.

To better utilize the optical fiber bandwidth and enhance the communication capability of the RoF system, this paper combines photonic vector modulation and optical millimeter-wave generation techniques, proposing an 18-fold frequency 16 quadrature amplitude modulation (QAM) millimeter-wave generation scheme based on polarization division multiplexing (PDM). The system consists of two parallel modules: frequency doubling and vector modulation. In the frequency doubling module, two dual-parallel Mach-Zehnder modulators (DP-MZM) and an optical phase shifter are used to generate the ±6th-order optical sidebands. After passing through a semiconductor optical amplifier (SOA), four-wave mixing effects are induced, and the 18th-order sidebands are obtained through filtering. In the vector modulation module, eight 10 Gbit/s binary NRZ signals drive the DP-MZM, and polarization multiplexing technology is applied to implement 16QAM optical domain modulation on two orthogonal polarization directions. The PDM-16QAM signal is coupled with the 18th-order optical sidebands and, after photodetection, an 18-fold frequency PDM-16QAM signal is generated. Simulation analysis shows that when the photodetector's received power is ?25 dBm, the signal-to-noise ratio (SNR) of the system is greater than 20.5 dB, and after 30 km transmission through single-mode optical fiber, the system performance remains good. Even when there are fluctuations in the SOA injection current and laser linewidth within a certain range, the bit error rate (BER) of the system remains below 3.8×10?3.

Optical fingerprint liveness detection plays a crucial role in preventing spoofing attacks on fingerprint recognition systems. Existing deep learning-based methods require large amounts of labeled data, while fingerprint image acquisition remains challenging. A few-shot optical fingerprint liveness detection method, featuring the fusion of spatial and frequency domain features, has been proposed for few-shot scenarios. Performance in liveness detection under few-shot conditions is enhanced using a bidirectional cross-domain attention mechanism and a high-frequency enhancement factor. Experimental results demonstrate outstanding performance on two benchmark datasets. With only 10 samples, the average classification error rate (ACER) reaches as low as 0.21% and 0.45%, outperforming existing methods. Notably, excellent adaptability in cross-sensor detection is shown. The method expands the practical applications of fingerprint liveness detection technology.

A measurement method for mapping the reflectivity distribution of curved high-reflectivity mirrors based on optical feedback cavity ring-down (OF-CRD) technique is introduced. The setup consists of a high-stability folded optical cavity and a high-precision positioning system with 5 degrees of freedom (DOF). By mathematical modeling, we established a universal mathematical relationship between the curved surface described by mathematical formula and the required adjustment for sample positioning, enabling dynamic five-dimensional compensation for optical elements with varying curvatures, apertures, and surface profiles. Through high-precision automated scanning strategy, the high-reflectivity distributions of samples with different surface profiles, apertures, and curvature diameters are obtained, this measurement is achieved by two-dimensionally raster-scanning while compensating for the other three dimensions (depth, pitch, and yaw) of the samples using a control program to ensure strict normal alignment between the probe beam and local surface throughout the measurement process. A reflectivity measurement repeatability error at the part-per-million (ppm) level is experimentally achieved. Good agreement is observed between the CRD-measured reflectivity profile and the grayscale image obtained by a laser confocal microscopy. Compared with the reflectivity values obtained by manual high-precision alignment, both reflectivity distributions obtained via automatic and manual alignments are consistent, demonstrating the reliability of the reflectivity distribution obtained with the experimental apparatus.

Bone tissue is a heterogeneous material with a complex structure. Large cracks are prone to propagate into the bone prolonging postoperative recovery. A pulsed laser is used to cut the bone tissue, and a heterogeneous structure bone model related to the direction of the osteon is established. The stress intensity factors in the directions transverse, parallel, and across to the osteon are 2.70, 2.03, and 1.94 MPa·m0.5, respectively. The surface roughness in the directions transverse, parallel, and across to the osteon are 10.14, 7.12, and 6.98 μm, respectively. The stress intensity factor and roughness of the laser surface cut in the direction transverse to the osteons are higher compared with the parallel and across directions. The value of stress intensity factor, surface roughness and the crack propagation patterns are similar when the laser cutting direction is parallel and across to the osteons. Results show that the laser cutting only needs to consider two characteristic directions, i.e., the directions perpendicular and parallel to the osteon. The roughness of laser-cut surfaces in the directions, perpendicular, parallel, and across to the osteon is lower than that of mechanical-cut surface, indicating that laser cutting is more conducive to postoperative bone healing.

When measuring the front surfaces of transparent objects by using phase measuring deflectometry (PMD), the reflections from the front and back surfaces of the object are superimposed, resulting in parasitic reflection, which makes it difficult to accurately reconstruct the front surface of objects. In this paper, we proposed a front-surface PMD method that suppresses parasitic reflections of transparent objects. Firstly, the initial phase of the front surface was extracted by continuous wavelet transform. Then, an optimized model was constructed by combining the multi-frequency phase-shifting method to obtain the accurate phase. Finally, the gradient integral was used to restore the three-dimensional (3D) morphology of the transparent object surface. The surfaces of transparent glasses and plano-convex lenses were measured using the above theory. Compared with the multi-frequency phase-shifting method, the reconstruction error of the 3 mm glass plate decreased from 21.81 μm to 15.72 μm, the error of the 4 mm glass plate is reduced from 19.98 μm to 13.46 μm, and the radius of curvature error of the plano-convex lens is reduced from 39.44 μm to 16.59 μm, thereby improving the accuracy of the front surface of transparent objects measurements.

In recent years, research on the dynamic regulation of electromagnetic wave absorbers using graphene has attracted extensive attention. In this paper, a patterned graphene absorber is designed with a catenary, and the calculated results show that the absorber achieves perfect dual-frequency absorption at 5.57 THz and 7.11 THz in the terahertz frequency band in the TE wave mode. The analysis of the electric field strength and current distribution on the surface of the graphene layer shows that the perfect absorption of the dual frequency is related to the electric dipole resonance caused by the local surface plasmon excitation of the graphene layer. On this basis, the simulation of the relationship between the resonant absorption frequency and the geometric parameters of the absorber structure, the coupled bias voltage and the incident angle shows that the absorber can effectively realize the dynamic control of the absorption, and the structure can also reflect the absorption rate of more than 90% for a large range of incidence angle (0° to 40°).

Addressing the challenge of unclear segmentation boundaries arising from multi-component aliasing in coke optical tissue images, this paper proposes a MD-UNet semantic segmentation model. This model employs VGG16 as its backbone network and incorporates the CloAttention module at the deepest level of the encoder. By leveraging context-aware local enhancement and a global attention mechanism, CloAttention enables the model to focus better on critical image regions and enhances the perception of the complex textures inherent in coke optical tissues. Furthermore, a multi-branch dilated fusion (MBDF) module has been designed to replace the conventional convolution modules in the decoder. This substitution aims to effectively preserve and integrate multi-scale information, thereby enriching feature representation and mitigating information loss and detail blurring. Finally, the GELU activation function is adopted in place of ReLU to address the vanishing gradient problem encountered during network training. Comparative experiments on semantic segmentation models demonstrate that the proposed MD-UNet model achieves the most superior segmentation performance on coke optical tissues, reaching mIoU and F1-Score values of 88.72% and 94.28%, respectively. These results significantly outperform traditional semantic segmentation models, thereby validating the effectiveness of MD-UNet in enhancing the segmentation accuracy of coke optical tissues.

The optical performance of the microscope objective lens directly affects the quality of microscopic imaging, so it is of great significance to detect its wavefront aberration. A method for detecting the aberration of a microscopic objective lens based on a Hartmann wavefront sensor was proposed. This method employed the two-sphere method to calibrate systematic errors, enabling aberration characterization of microscope objectives. The model was established and simulated and analysed, and the results show that measured wavefront aberrations closely matched actual values, verifying model validity. The experimental setup was constructed, and the aberration detection of the microscope objective was carried out. The measurement shows the objective lens's root mean square (RMS) detection accuracy is ≤ 10 nm, with a repeatability accuracy of < 0.3 nm. This confirms the practical feasibility of the detection model. The method is simple and easy to set up, providing an detection model for wavefront aberration detection of medium and low power finite-conjugate microscope objectives.