Continuous-wave terahertz multi-plane in-line digital holography

Terahertz digital holography is a non-scanning and real time method for reconstructing the absorption and phase distributions of the wave-front diffracted by a given sample simultaneously in the terahertz region. A continuous-wave terahertz in-line digital holographic multi-plane imaging method is presented here for achieving a three-dimensional shape of a specific portion of a sample with the best possible focus. The three enhancement techniques of synthetic aperture, autofocusing and phase retrieval are applied to the single plane recordings for achieving a high resolution, good quality and optimally focused reconstructed image. Later, multi-plane reconstructed images are processed with the threshold mask and a three dimensional profile of the sample is obtained. Experimental verification confirms that the proposed method is a valid tool for acquiring multi-plane information of a target in the terahertz range.