Absolute distance measurement of optically rough objects using asynchronous-optical-sampling terahertz impulse ranging

作者：Yasui Takeshi^*; Kabetani Yasuhiro; Ohgi Yoshiyuki; Yokoyama Shuko; Araki Tsutomu

来源：Applied Optics, 2010, 49(28): 5262-5270.

DOI：10.1364/AO.49.005262

We report on a real-time terahertz (THz) impulse ranging (IPR) system based on a combination of time-of-flight measurement of pulsed THz radiation and the asynchronous-optical-sampling (ASOPS) technique. The insensitivity of THz radiation to optical scattering enables the detection of various objects having optically rough surfaces. The temporal magnification capability unique to ASOPS achieves precise distance measurements of a stationary target at an accuracy of -551 mu m and a resolution of 113 mu m. Furthermore, ASOPS THz IPR is effectively applied to real-time distance measurements of a moving target at a scan rate of 10 Hz. Finally, we demonstrate the application of ASOPS THz IPR to a shape measurement of an optically rough surface and a thickness measurement of a paint film, showing the promise of further expanding the application scope of ASOPS THz IPR. The reported method will become a powerful tool for nondestructive inspection of large-scale structures.

• 出版日期2010-10-1