Terahertz Phase Retrieval Imaging in Reflection

Collaboration with ITMO University about Terahertz

After the visit of the great museum of optics in ITMO, Saint Petersbourg, Russia, an interesting discussion started with ITMO colleagues about terahertz phase retrieval and holography. We were also pleased to invite Nicholay Petrov at IMS Laboratory in Bordeaux. I am delighted to present here the results of this research in collaboration with our colleagues from ITMO.

Abstract of terahertz phase retrieval article

Terahertz phase recovery is a promising method for evaluating the complex properties of a diffracted wave using an iterative processing algorithm. In this letter, we will demonstrate the implementation of this method in reflection geometry with a continuous wave system operating at a frequency of 287 GHz. To ensure a high signal-to-noise ratio in the measured data set, we have proposed a double parallel recording circuit with a detector and two lock-in amplifiers, operating with an additional sensitivity adjustment. This provided a higher digital aperture than conventional focal plane scanning during the raster scanning. A special digital interferometric post-processing procedure was applied to obtain a map of surface heights by phase distribution reconstructed in the irradiated area of the object.

Double lock-in amplifier configuration allow a high sensitivity and a high dynamic range

Access to holography article and citation

https://www.researchgate.net/publication/342398739_Terahertz_Phase_Retrieval_Imaging_in_Reflection

Petrov, N. V., Perraud, J. B., Chopard, A., Guillet, J. P., Smolyanskaya, O. A., & Mounaix, P. (2020). Terahertz Phase Retrieval Imaging in Reflection. Optics Letters.

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