High-resolution THz time-of-flight imaging with reflective optics

In this study, we developed THz time-of-flight imaging based on all-reflective optics to preserve the high-frequency components of a THz antenna for inline applications. In particular, asynchronous optical sampling enables rapid scanning at 200 Hz per pixel with a full time-delay of 10 ns. This configuration enabled us to obtain phase and amplitude images with a spatial resolution of 0.5 mm for non-destructive testing applications such as finding defects in packaged chips. Also, we introduced conformal mapping techniques for maintaining high spatial resolution, applicable for objects with variable heights.