隐藏物的连续太赫兹反射扫描成像实验

Experiments on Continuous-Wave Terahertz Reflection-Mode Imaging for Concealed Objects

太赫兹成像的优势在于能够穿透大多数非金属、非极性物质进行隐藏物的探测,而且不会对生物体造成伤害。其中太赫兹反射成像具有更为广泛的应用空间。由于对常见包装品和衣物的穿透能力在太赫兹反射成像系统的评估中十分重要,故利用CO2抽运太赫兹激光器所搭建的2.52THz反射扫描成像系统对剃须刀、铅笔字、5角硬币、金属纪念币和星卡等多种物体进行了穿透力实验;以纸、纸质快递信封和实验服为遮挡物,进行了成像对比分析。实验结果表明,该成像装置可以穿透单层实验服或单层纸制信封对目标成反射像,最大插入损耗近42dB。

Terahertz （THz） imaging has the advantages that THz radiation can penetrate most nonmetal and nonpolar materials for concealed objects detection, while it is harmless to the organisms. THz reflection-mode imaging has a more widely application range. Thus the penetrating ability for common packaging materials and clothes becomes very important to evaluate a THz reflection-mode imaging system. Therefore, penetration experiments are carried out by using a 2.52 THz reflection-mode scanning system. The system is constructed based on a CO2 pumped THz laser. The imaging targets are a razor blade, a penciled character, a 50 cents coin, a metal commemorative coin, and Siemens star. Papers, paper envelopes, and lab gowns are used as the shelters, and the imaging results are compared and analyzed, The experiment results demonstrate that the system can image through one layer of the lab gown or a paper envelope. The maximum insertion loss approaches 42 dB.