Zolliker Peter, Hack Erwin
Opt Express. 2015 May 4;23(9):10957-67. doi: 10.1364/OE.23.010957.
We demonstrate a digital holographic setup for Terahertz imaging of surfaces in reflection. The set-up is based on a high-power continuous wave (CW) THz laser and a high-resolution (640 × 480 pixel) bolometer detector array. Wave propagation to non-parallel planes is used to reconstruct the object surface that is rotated relative to the detector plane. In addition we implement synthetic aperture methods for resolution enhancement and compare Fourier transform phase retrieval to phase stepping methods. A lateral resolution of 200 μm and a relative phase sensitivity of about 0.4 rad corresponding to a depth resolution of 6 μm are estimated from reconstructed images of two specially prepared test targets, respectively. We highlight the use of digital THz holography for surface profilometry as well as its potential for video-rate imaging.
我们展示了一种用于反射式太赫兹表面成像的数字全息装置。该装置基于高功率连续波（CW）太赫兹激光器和高分辨率（640×480像素）测辐射热计探测器阵列。利用波传播到非平行平面来重建相对于探测器平面旋转的物体表面。此外，我们还实现了用于分辨率增强的合成孔径方法，并将傅里叶变换相位检索与相位步进方法进行了比较。分别从两个特别制备的测试目标的重建图像中估计出横向分辨率为200μm，相对相位灵敏度约为0.4rad，对应深度分辨率为6μm。我们强调了数字太赫兹全息术在表面轮廓测量中的应用及其在视频速率成像方面的潜力。
