Optical Rectification and Electro-Optic Sampling in Quartz

TL;DR

This paper demonstrates that quartz can be used as a reliable, high-field, echo-free electro-optic medium for terahertz detection, with broad response up to 8 THz and surface contributions playing a significant role.

Contribution

It introduces thin quartz plates as effective, reliable THz electro-optic sensors with broad bandwidth and surface nonlinear effects, expanding the applications of quartz in THz detection.

Findings

Quartz exhibits broad EO and THz OR responses up to ~8 THz.

Surface contributions significantly influence quartz's nonlinear susceptibility.

Quartz can measure intense THz pulses without saturation effects.

Abstract

We report electro-optic sampling (EOS) response and terahertz (THz) optical rectification (OR) in z-cut alpha-quartz. Due to its small effective second-order nonlinearity, echo-free waveform of intense THz pulses with a few MV/cm electric-field strength can be measured faithfully with no saturation effect. Both its OR and EOS responses are broad with extension up to ~8 THz. Strikingly, the latter responses are independent of the crystal thickness, a plausible indication of strong surface contribution to the total second-order nonlinear susceptibility of quartz. Our study introduces thin quartz plates as the reliable THz electro-optic medium for echo-free, high field THz detection.