Nonlinear Generation, Compression and Spatio-Temporal Analysis of GV/cm-Class Femtosecond Mid-Infrared Transients

TL;DR

This paper presents a high-repetition-rate femtosecond mid-infrared source capable of generating extremely strong electric fields, enabling advanced spectroscopic techniques like electro-optic sampling to study ultrafast phenomena.

Contribution

The work introduces a novel nonlinear generation scheme producing intense, stable mid-infrared transients with high repetition rate, surpassing previous field strength and bandwidth limitations.

Findings

Electric field strength exceeds 330 MV/cm at 45 THz

Demonstration of solitonic self-compression and octave-spanning supercontinua

Support for advanced ultrafast spectroscopic methods

Abstract

A thin-disk regenerative amplifier with 3 kHz repetition rate pumps a second-order nonlinear mixing scheme providing femtosecond transients of maximum electric field strength beyond 330 MV/cm at a center frequency of 45 THz. This value surpasses field conditions present at sub-molecular dimensions of matter. The inherent competition between efficiency and bandwidth in parametric downconversion is overcome with a third-order nonlinear step of self-phase modulation. The high repetition rate, versatility, beam quality and passive phase stability of our system support advanced spectroscopic approaches like electro-optic sampling. With this technique, we study solitonic self-compression and octave-spanning supercontinua directly on a subcycle scale.