Open AccessThickness dependence of the terahertz response in 〈110〉-oriented GaAs crystals for electro-optic sampling at 155 µm
Author(s) -
Zhenyu Zhao,
Andre Schwagmann,
F. Ospald,
D. C. Driscoll,
Hong Lü,
A. C. Gossard,
J. H. Smet
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.015956
Subject(s) - terahertz radiation , optics , materials science , crystal (programming language) , bandwidth (computing) , attenuation coefficient , optoelectronics , terahertz spectroscopy and technology , common emitter , absorption (acoustics) , physics , computer network , computer science , programming language
We experimentally study the thickness dependence of the terahertz (THz) response in {110}-oriented GaAs crystals for free space electro-optic sampling at 1.55 microm. The THz response bandwidths are analyzed and simulated under phase-matching condition with a model frequency response function. The results indicate that the detection bandwidth increases from 2 THz to 3 THz when the thickness of GaAs is reduced from 2 mm to 1 mm. Below 1 mm, the detected bandwidth is increasingly limited by the emitter characteristics and the finite probe pulse duration. The broadest bandwidth in experiment reaches 3.3 THz when using a 0.2 mm thick crystal, while it exceeds 5 THz in theory. The THz response sensitivity was studied experimentally and modeled taking into account the absorption of the THz radiation in the GaAs crystal. While absorption was found to be negligible for the crystal thickness range studied here, strong saturation is predicted theoretically for crystal thicknesses exceeding 5 mm.