Seven‐Fold Compression of Mid‐Infrared Pulses Using a Series of Titanium Dioxide Plates

Abstract

ABSTRACT We demonstrate a compact approach for generating 2‐cycle mid‐infrared pulses centered at 2.038 µm using bulk TiO 2 plates for nonlinear spectral broadening and self‐compression. Starting from a passively CEP‐stable idler pulse produced by an optical parametric amplifier, the beam is transmitted through a sequence of three 500 µm‐thick TiO 2 plates operated near the material's zero‐dispersion wavelength. The pulse duration is reduced from 103.9 to 14.1 fs without subsequent dispersion‐compensation stages, while the spectral bandwidth broadens from 10.85 to 84.42 THz and the output pulse energy is 42 µJ, corresponding to 76.3% transmission efficiency. The compressed output exhibits a CEP standard deviation of 334 mrad over a 50 min measurement. These results establish bulk TiO 2 self‐compression as a simple and scalable platform for generating mid‐infrared few‐cycle pulses.