Algorithm for high-resolution single-shot THz measurement using in-line spectral interferometry with chirped pulses

Abstract

Z. P. Jiang and X. C. Zhang demonstrated a single-shot THz diagnostic based on spectral encoding of a chirped optical probe pulse [Appl. Phys. Lett. 72, 1945 (1998)]. This technique is thought to have an inherent uncertainty principle-imposed temporal resolution limitations. In this letter, we describe a method to recover the THz field without distortions, surpassing previous resolution limitations. Our approach is based on interpreting the spectral encoding experiment as in-line spectral interferometry, analogous to Gabor’s in-line spatial holography [D. Gabor, Nature (London) 161, 777 (1948)]. We recover the THz field from the interferogram and the characterized probe by using Tikhonov regularization combined with lower and upper triangular decomposition.

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“…A fourth technique (spectral encoding geometry [9][10][11]) is based on EO modulation by the THz pulse of a chirped laser pulse. Analysis of the spectrum of the modulated laser pulse yields information of the THz pulse.…”

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