Abstract-Optical rectification in a chalcopyrite AgGaSe2 crystal for broadband terahertz radiation generation

B. N. Carnio, K. T. Zawilski, P. G. Schunemann, and A. Y. Elezzabi

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-44-11-2867

We report on optical rectification in a ⟨110⟩$⟨110⟩$ AgGaSe2${\mathrm{AgGaSe}}_2$ crystal that produces terahertz (THz) electric field pulses across the broad frequency range of 0.02–4 THz. Due to the large coherence length of the AgGaSe2${\mathrm{AgGaSe}}_2$ crystal (>4$>4$ times larger than that of CdSiP2${\mathrm{CdSiP}}_2$ and ZnGeP2${\mathrm{ZnGeP}}_2$), in-phase THz radiation is produced over the entire crystal thickness of 485 μm. Furthermore, THz time-domain spectroscopy is used to determine the ordinary and extraordinary refractive indices and extinction coefficients of the uniaxial AgGaSe2${\mathrm{AgGaSe}}_2$ crystal across the broad spectral range of 0.5–2.9 THz, encompassing several phonon resonances.

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