High-field THz source centered at 2.6 THz

TL;DR

This paper presents a novel tabletop high-field THz source at 2.6 THz using optical rectification in GaP, achieving peak fields over 300 kV/cm and promising higher fields with increased pulse energy, enabling new THz applications.

Contribution

The work introduces a new high-field THz generation method using tilted-pulse-front phase matching in GaP with etched phase gratings, achieving high peak fields at 2.6 THz.

Findings

Peak THz fields exceed 300 kV/cm with current setup.

Efficiency saturates at 0.57 mJ pulse energy.

Potential to reach 866 kV/cm with higher pulse energy.

Abstract

We demonstrate a table-top high-field terahertz (THz) source based on optical rectification of a collimated near-infrared pulse in gallium phosphide (GaP) to produce peak fields exceeding 300 kV/cm with a spectrum centered at 2.6 THz. The experimental configuration, based on tilted-pulse-front phase matching, is implemented with a phase grating etched directly onto the front surface of the GaP crystal. Although the THz generation efficiency starts showing a saturation onset as the near-infrared pulse energy reaches 0.57 mJ, we can expect our configuration to yield THz peak fields up to 866 kV/cm when a 5 mJ generation NIR pulse is used. This work paves the way towards broadband, high-field THz sources able to access a new class of THz coherent control and nonlinear phenomena driven at frequencies above 2 THz.