Selenium gallium barium crystals. Courtesy of Shenyang Automation
Shenyang, January 25 (Reporter Wang Jingwei) The Shenyang Institute of Automation of the Chinese Academy of Sciences (hereinafter referred to as the Shenyang Institute of Automation) released a message on January 25 that the institute has made key technological breakthroughs in the field of infrared detection, realized the 3-8 micron mid-infrared high sensitivity detection based on selenium gallium barium crystals, and the detection sensitivity index of nanosecond pulses has reached the international advanced level and realized the localization of the system. This technology will provide a powerful detection tool for the mainland to carry out cutting-edge scientific research in the fields of biology, medical treatment, chemical industry and other fields, and the relevant results have been published by the international authoritative journal of optics "Optica".
Researchers conduct tests in the laboratory. Courtesy of Shenyang Automation
It is reported that compared with the traditional visible light near-infrared band, the resonance phenomenon between mid-infrared light and molecules can greatly improve the signal-to-noise ratio of spectral measurement, thereby realizing the effective identification of material components. Therefore, the mid-infrared detection technology is of great significance for promoting scientific exploration such as life science and physical property analysis, as well as practical applications such as environmental protection, chemical industry, and medical diagnosis.
At present, mid-infrared detection mainly uses two direct detection methods of thermal detection and photoelectric detection, and the existing performance is difficult to meet the needs of scientists for accurate detection of trace substances, and detection sensitivity has become a bottleneck problem in the mid-infrared system.
Qi Feng, a researcher at Shenyang Institute of Automation, said: "In view of the current bottleneck problem of mid-infrared detection, we proposed a solution based on laser frequency conversion technology, and designed and built an experimental system. Its working principle is to convert the weak mid-infrared signal into a near-infrared signal with high efficiency, the near-infrared light carries the information of the mid-infrared light and is easy to detect, and the detection sensitivity of the mid-infrared signal is greatly improved through this indirect detection method. ”
Mid-infrared detection system based on laser frequency conversion technology. Courtesy of Shenyang Automation
According to Qi Feng, after in-depth analysis and study of the optical properties of a variety of crystals, the scientific research team targeted the selenium gallium barium crystal, which was developed by the Yao Jiyong team of the Institute of Physics and Chemistry of the Chinese Academy of Sciences. "Selenium gallium barium crystal is usually used as a wave source, we boldly tried to use it as part of the detection system, on the basis of mastering its optical characteristics, designed a high-performance optical parameter oscillator, optimized the phase matching conditions, solved the problem of strong background noise suppression in the weak signal environment, and realized the mid-infrared system of transceiver integration."
Through the experimental test of nanosecond pulses, it is shown that the detection sensitivity achievable by the system is currently 100 times better than that of the tellurium mercury detector, which realizes the effective detection of the nanosecond pulse of the flying focus level, the dynamic range of the system exceeds 110 decibels, and the uniform response in the wide frequency range can reach 1.4 octaves, which is better than the traditional direct detection system.
Shi Zelin, director of the Shenyang Institute of Automation and director of the Key Laboratory of Optoelectronic Information Processing of the Chinese Academy of Sciences, said that in the photoelectric detection research, the institute adheres to demand traction and problem orientation, and overcomes problems such as high-sensitivity infrared detection through new mechanisms and new methods. The realization of mid-infrared high-sensitivity detection based on selenium gallium barium crystals will make it possible to bring new scientific means to the fields of biology, medical treatment, and chemical industry, making it possible to do things that could not be done before. (End)