The impact of the response speed of a microelectromechanical system (MEMS) bolometer on the quality of terahertz (THz) imaging with rapid scan has been investigated and compared with a pyroelectric detector (PED). The imaging system was an active imaging composed of the MEMS bolometer, THz quantum cascade laser, and two-dimensional translation stage. The scanning process of the imaging system consisted of continuous scans in the X direction and step scans in the Z direction. The MEMS bolometer had a beam resonator with a resonant peak of 422 kHz, and it was operated in the frequency modulation detection mode. The frequency shifts in the resonant peak due to the irradiation of the THz waves were tracked using the phase-locked loop system built in the lock-in amplifier. In the measurement of the response characteristics using a 100-μm pinhole, the peak intensity was almost constant against the stage speed in the case of the MEMS bolometer. For the PED, there was a decrease in the peak intensity and delay in the peak positions with increasing stage speed due to the insufficient response speed. When the images were acquired using the MEMS bolometer with a stage speed of 25 mm/s, fine structures of a metal bookmark were clearly observed and no degradation in the resolution was observed with changing stage speed. In the case of the PED, the resolution gradually degraded with increasing stage speed.

中文翻译：

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使用MEMS测距仪进行快速扫描THz成像

已经研究了微机电系统辐射热计的响应速度对快速扫描的太赫兹（THz）成像质量的影响，并将其与热释电探测器（PED）进行了比较。成像系统是一个主动成像，由MEMS热辐射计，太赫兹量子级联激光器和二维平移台组成。成像系统的扫描过程包括在X方向上连续扫描和在Z方向上步进扫描方向。MEMS热辐射计具有一个波束谐振器，其谐振峰值为422 kHz，并且以频率调制检测模式运行。使用内置在锁相放大器中的锁相环系统跟踪了由于太赫兹波的照射而导致的共振峰中的频移。在使用100μm针孔的响应特性测量中，对于MEMS辐射热计，峰值强度相对于载物台速度几乎恒定。对于PED，由于响应速度不足，随着工作台速度的增加，峰强度降低，峰位置延迟。当使用MEMS辐射热计以25 mm / s的载物台速度采集图像时，可以清楚地观察到金属书签的精细结构，并且随着载物台速度的变化，分辨率也不会降低。