Shear interferometry for terahertz wavefront sensing

Mostafa Agour; Claas Falldorf; Fatima Taleb; Enrique Castro-Camus; Martin Koch; Ralf B. Bergmann

doi:10.1117/12.2621696

31 May 2022 Shear interferometry for terahertz wavefront sensing

Mostafa Agour, Claas Falldorf, Fatima Taleb, Enrique Castro-Camus, Martin Koch, Ralf B. Bergmann

Proceedings Volume 12134, Terahertz Photonics II; 121340B (2022) https://doi.org/10.1117/12.2621696
Event: SPIE Photonics Europe, 2022, Strasbourg, France

Abstract

We propose a new solution for sensing a terahertz (THz) wavefront based on a THz reference-less shear interferometer. The key component of the experimental configuration of the proposed interferometer is a THz Ronchi phase grating (RPG). The RPG is custom designed and fabricated for a 0.28 THz source using mechanical milling on a block of high-density polyethylene (HDPE) with a computer numerical control (CNC) machine. It acts as a shearing element that generates two diffraction orders, thereby creating two laterally shifted copies of the investigated wavefront in the sensor plane where a THz camera is placed. The direction of the shear can be varied by rotating the grating. Since the grating is a phase grating, the diffraction efficiency is very high. The approach is verified experimentally by demonstrating interferograms of a spherical wave and wavefront reconstruction from five different shears using a gradient-based iterative process.

Conference Presentation

Citation Download Citation

Mostafa Agour, Claas Falldorf, Fatima Taleb, Enrique Castro-Camus, Martin Koch, and Ralf B. Bergmann "Shear interferometry for terahertz wavefront sensing", Proc. SPIE 12134, Terahertz Photonics II, 121340B (31 May 2022); https://doi.org/10.1117/12.2621696

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