Sn doping is an effective way to improve the response rate of Ga₂O₃ film based solar-blind detectors. In this paper, Sn-doped Ga₂O₃ films were prepared on a sapphire substrate by radio frequency magnetron sputtering. The films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and ultraviolet visible spectroscopy, and the effect of annealing atmosphere on the properties of films was studied. The Ga₂O₃ films changed from amorphous to β-Ga₂O₃ after annealing at 900 °C. The films were composed of micro crystalline particles with a diameter of about 5–20 nm. The β-Ga₂O₃ had high transmittance for wavelengths above 300 nm, and obvious absorption for solar-blind signals at 200–280 nm. The metal semiconductor metal type solar-blind detectors were prepared. The detector based on Sn-doped β-Ga₂O₃ thin film annealed in N₂ has the best response performance to 254 nm light. The photo-current is 10 μA at 20 V, the dark-current is 5.76 pA, the photo dark current ratio is 1.7 × 10⁶, the response rate is 12.47 A/W, the external quantum efficiency is 6.09 × 10³%, the specific detection rate is 2.61 × 10¹² Jones, the response time and recovery time are 378 and 90 ms, respectively.

Face recognition technology has great prospects for practical applications. Three-dimensional (3D) human faces are becoming more and more important in consideration of the limits of two-dimensional face recognition. We propose an active binocular setup to obtain a 3D colorful human face using the band-limited binary patterns (BBLP) method. Two grayscale cameras capture the BBLP projected onto the target of human face by a digital light processing (DLP) projector synchronously. Then, a color camera captures a colorful image of the human face. The benefit of this system is that the 3D colorful human face can be obtained easily with an improved temporal correlation algorithm and the precalibration results between three cameras. The experimental results demonstrated the robustness, easy operation, and the high speed of this 3D imaging setup.

For manufacturing a fine optical glass lens, it is important to obtain a 3D profile of a semi-finished product with a rough surface. We develop an active binocular 3D scanning setup to measure the 3D profile of a rough surface optical element. Two cameras simultaneously capture the band-pass binary random patterns which are projected on the target object. The highlight of this system is using the temporal correlation technique to determine the stereo correspondence between the pixels of the two cameras. The 3D point cloud can be reconstructed by the triangulation principle. Experiment results confirmed that this method effectively measures the rough surface of an optical element with sufficient accuracy.