基于太赫兹量子级联激光器的实时成像研究进展

太赫兹(THz)实时成像是THz技术中颇具潜力的一个领域,具有成像速度快、成像分辨率高等特点,基于THz量子级联激光器(QCL)的实时成像系统是其中最重要的一种,系统体积小、重量轻、成像信噪比高等特点使其在实际应用中具有独特的优势。本文主要介绍了THz QCL器件及其实时成像系统的研究进展,采用超半球高阻硅透镜改善了THz QCL的输出激光,实现了准高斯光束输出,搭建了基于二维摆镜消干涉技术的THz实时成像系统,单帧成像光斑面积45mm×30 mm,实现了对刀片、药片的实时成像演示,成像分辨率优于0.5 mm;最后对成像系统激光源、成像光路和探测端的改进以及成像效果的改善方面进行了综述,并探讨了THz实时成像系统未来的发展趋势及其在材料分析和生物医学成像方面的应用前景。

Progress in real-time imaging based on terahertz quantum-cascade lasers

Terahertz(THz) real-time imaging is a promising field in most of THz technologies. It has lots of features such as fast imaging, high-resolution imaging, etc. The imaging system based on THz quantum-cascade laser(QCL) is one of the most important THz imaging techologies. This type of imaging system has a unique advantage in applications with the features of small size, light weight, and high SNR. In this paper, the research progress of THz QCL and the related real-time imaging system are mainly presented. A hyper-hemispherical high-resistivity silicon lens is used to improve the beam quality of THz QCL. Then a quasi-Gaussian light beam is acquired in imaging system. A THz real-time imaging system is constructed by employing a two dimensional wobbling mirror to eliminate the interference of the THz light. A beam spot size of 45 mm×30 mm for single frame imaging is obtained. The real-time imaging for blade and tablets is demonstrated with a resolution better than 0.5 mm. Finally, the improvements of the source, optics, and detector array of the system and the imaging effect are summarized. The application prospect in material analysis and bio-medical imaging as well as the future trends of the real-time imaging system are discussed.