Terahertz (THz) waves have characteristics such as low energy, strong penetration, and high resolution. Therefore, THz imaging technology has broad prospects in areas such as security inspection, medical diagnosis, and non-destructive testing. As an important component of THz imaging systems, the performance of THz detectors has a significant impact on imaging resolution and speed. Field effect transistor (FET) THz detectors, due to their characteristics of room temperature operation, easy large-scale integration, and fast response speed, have enormous potential in imaging applications. This paper reviews the research progress of FET THz detectors in the field of THz imaging in recent years, including advances in imaging arrays, material selection, and analysis of existing design and manufacturing issues It points out that the antenna and pixel spacing are important factors limiting large-scale arraying. Based on this, it provides an outlook on future research directions, indicating that new materials and structural designs will further improve device performance,achieving faster and dearer THz imaging

X-ray morphology testing is a non-destructive testing method for detecting the integrity of the crystal structure of samples. Surface morphology testing of tellurium zine cadmium (111) wafers was conducted using a high-resolution digital X-ray morphometer, and the quality of tellurium zinc cadmium crystals was evaluated by defect form and density. After extensive data analysis, five common defects in tellurium zine cadmium crystals have been identified: scratches, voids, small angle grain boundaries, twinning and impurities. Based on specific processes, the reasons for the formation of 5 types of defects were explained and analyzed, and constructive suggestions were put forward for the growth and processing technology of tellurium zine cadmium crystals, which is conducive to obtaining high-quality substrate materials and improving the quality of epitaxial tellurium cadmium mercury films

Wet etching can effectively remove the damage caused by mechanical effects during the back thinning process of chips, and improve the quantum efficiency of devices. In order to obtain a suitable wet etching method, three different acidic indium antimonide etching solutions were studied, mainly consisting of hydrofluoric acid, hydrochloric acid and lactic acid. The optimal etching solution system was selected based on the characterization results of metallographic microscopy and atomic force microscopy. On this basis, the concentration and ratio of hydrofluoric acid etching solution were further optimized, and the etching rate and consistency of the etching solution were studied. Finally, the optimized etching solution was used to treat the indium antimonide chip, and the performance of the chip at 77 K temperature was studied. The planar results show that the etching solution can effectively remove the damage on the chip surface, and the device voltage signal reaches 485 mV. The successful application of wet etching technology in surface treatment of chip back thinning has important significance for the research of indium antimonide back treatment technology.

The cryocooler is the key component of Stirling refrigerator, its parameters directly affect the working efficiency of the refrigerator, and the stainless steel wire mesh is the filler of regenerator. In this paper, the influence of wire mesh parameters on the performance of Stirling refrigerator is analyzed. The flow field distribution and pressure distribution in the regenerator are obtained by computational fluid dynamics(CFD) simulation. The relationship between the void ratio and flow rate is obtained by means of flow measurement system. The larger the void ratio is, the larger the internal flow rate of the regenerator is, and the cooling time increases. The effect of different void ratios and numbers of meshes on the performance is studied by experiments The results show that when the number of meshes is the same and the void ratio of regenerator is 0. 61-0. 78, the cooling time of refrigerator increases with the increase of void ratio When the number of regenerator wire meshes is 600-800, the cooling time of the refrigerator decreases with the increase of the number of regenerator wire meshes filling.

Terahertz air-based coherent detection technology is an important detection method in the field of terahertz. By using liquid water (or other liquids) as the interaction medium, this detection technology can be improved. The basic principle of this detection technology is introduced, and the effect of laser second harmonic and its intensity on the detection results are analyzed in detail The characteristics and properties of the detection results in the time and frequency domains under different ratios of terahertz electric field and intensity signal at different intensities are analyzed The evolution law of the technology from incoherence to coherence at different laser second harmonic intensities is analyzed, as well as the influence of the intensity of the probe and the nonlinear coefficient of medium on the detection. The application of solid-state materials in this technology is discussed. The effects of gas, liquid, and solid-state materials on the generation of second harmonics and detection results are compared in this technology. The research results are helpful for understanding and using liquid-based terahertz broadband coherent detection technology.

In the conventional land use remote sensing updating and interpretation process, there are some shortcomings such as lack of effective control omission and low efficiency of interpretation operation. In this paper, the relevant reasons are analyzed, and on the basis of practice, an optimized update interpretation process is proposed. In order to improve the concentration of interpreters and increase the automation of editing operations, the optimization process optimizes part of the routine process, especially the original comprehensive search process is optimized to split the land use layer by type and search the change by type, so as to solve the problem of missing judgment. At the same time, some necessary links are newly established, and some complicated manual operations are handed over to application software. The application practice shows that this optimized land use remote sensing update interpretation process not only simplifies the tasks of each link, but also improves the pertinence of understanding translation and the automation of operation, which helps to reduce the missing judgment and editing errors in the interpretation process. Although the interpretation process is increased, the overall interpretation time is reduced and the interpretation efficiency is improved