Flowing cryogenic liquid target for terahertz wave generation

TL;DR

This paper demonstrates broadband terahertz wave generation from a flowing cryogenic liquid nitrogen target under high-repetition-rate laser excitation, offering a debris-free and sustainable method for terahertz source development.

Contribution

It introduces a novel flowing cryogenic liquid nitrogen target for terahertz generation, enabling debris-free, high-repetition-rate laser excitation and broader bandwidth emission compared to water.

Findings

Broadband terahertz emission observed from liquid nitrogen

Target sustains 1 kHz laser repetition rate

Terahertz peak field comparable to liquid water

Abstract

Terahertz wave emission from condensed matter excited by intense laser pulses not only reflects the details in laser-matter interaction but also offers bright terahertz wave sources. Flowing liquid targets possess the advantage of providing a fresh area for each laser pulse. To demonstrate a debris-free target under laser excitation, we investigate the use of liquid nitrogen as a target. By creating a flowing liquid nitrogen line in the ambient environment, we successfully observe broadband terahertz wave emission under short pulse excitation. Our cryogenic line is able to sustain the excitation of a high-repetition-rate (1 kHz) laser. The terahertz peak field emitted from liquid nitrogen is comparable to that from liquid water, yet a broader bandwidth is observed. This demonstration prompts new opportunities in choosing potential materials for studying terahertz wave generation process and in understanding laser-induced ionization in different liquids.