Towards generation of mJ-level ultrashort THz pulses by optical rectification

TL;DR

This paper explores optimizing optical rectification in LiNbO3 to generate ultrashort THz pulses with electric fields reaching hundreds of MV/cm and energies in the tens of millijoules, suitable for various advanced applications.

Contribution

It provides a detailed theoretical analysis and optimization strategies for generating high-field, high-energy THz pulses via optical rectification in LiNbO3, including cryogenic cooling and contact grating techniques.

Findings

Peak electric field of several MV/cm predicted at 0.3-1.5 THz

Potential to reach 100 MV/cm with focusing and contact grating

Generation of tens of mJ THz pulses feasible with optimized setup

Abstract

Optical rectification of ultrashort laser pulses in LiNbO3 by tilted-pulse-front excitation is a powerful way to generate near single-cycle terahertz (THz) pulses. Motivated by various applications, calculations were carried out to optimize the THz peak electric field strength. The results predict THz output with peak electric field strength on the MV/cm level in the 0.3-1.5 THz frequency range by using optimal pump pulse duration of about 500 fs, optimal crystal length, and cryogenic temperatures for reducing THz absorption in LiNbO3. The THz electric field strength can be increased further to tens of MV/cm by focusing. Using optimal conditions together with the contact grating technique THz pulses with 100 MV/cm field strength and energies on the tens-of-mJ scale are feasible.