Single-cycle THz pulses with amplitudes exceeding 1 MV/cm generated by optical rectification in LiNbO3

TL;DR

This paper demonstrates the generation of single-cycle terahertz pulses exceeding 1 MV/cm in amplitude using optical rectification in LiNbO3 with optimized tilted-pulse-front scheme, focusing geometry, and high efficiency.

Contribution

It introduces an optimized setup for generating high-amplitude single-cycle THz pulses via optical rectification in LiNbO3, achieving record electric field strengths.

Findings

Maximum THz electric field of 1.2 MV/cm achieved

Optimized tilted-pulse-front scheme improves efficiency

Focusing geometry enables near-diffraction-limited beam

Abstract

Using the tilted-pulse-intensity-front scheme, we generate single-cycle terahertz (THz) pulses by optical rectification of femtosecond laser pulses in LiNbO3. In the THz generation setup, the condition that the image of the grating coincides with the tilted-optical-pulse front is fulfilled to obtain optimal THz beam characteristics and pump-to-THz conversion efficiency. The designed focusing geometry enables tight focus of the collimated THz beam with a spot size close to the diffraction limit, and the maximum THz electric field of 1.2 MV/cm is obtained.