Efficient Generation of Intense Broadband Terahertz Pulses from Quartz

TL;DR

This paper presents a simple method to generate strong, broadband terahertz pulses from quartz, with tunable frequencies between 2-4 THz, suitable for advanced nonlinear spectroscopy and optical applications.

Contribution

It demonstrates that quartz can efficiently produce broadband THz pulses comparable to LiNbO3, expanding options for nonlinear optical crystal selection.

Findings

Broadband THz pulses with 1.2 microjoule energy generated from quartz.

Tunable center frequency between 2-4 THz achieved.

Quartz's efficiency rivals LiNbO3 over a broader spectral range.

Abstract

The intense terahertz (THz) pulses facilitate the observation of various nonlinear optical effects and manipulation of material properties. In this work, we report a convenient approach that can produce strong broadband terahertz pulses with center frequency tunable between 2-4 THz. The coherent THz light source with pulse energy of 1.2 microjoule can be generated from a low-cost crystalline quartz pumped by an ultrashort tilted wave-front pulse. Thanks to the wide transparent spectral window and high damage threshold, our theoretical analysis and experiment show that the optical rectification in quartz is as efficient as that in LiNbO3, but covers much broader spectral range. This work not only provides the light source that is urgently needed for nonlinear THz spectroscopy beyond 1 THz, but offers an alternative route in the selection of nonlinear optical crystals for optical frequency conversion.