Simple technique for the compression of nanojoule pulses from few-cycle laser oscillator to 1.7-cycle duration via nonlinear spectral broadening in diamond
Abstract
We report on a simple approach for the compression of fewcycle laser pulses generated in an ultrafast laser oscillator to a duration corresponding to 1.7 cycles of near-infrared light (compression factor of 1.44) by nonlinear spectral broadening in diamond and subsequent dispersion compensation using chirped mirrors. After the spectral broadening, the pulse spectrum spans over almost an octave (580-1000 nm at the -10 dB level).
The pulses are compressed by broadband-chirped mirrors and a wedge pair to a duration of 4.5 fs measured by spectral phase interferometry for direct electric-field reconstruction (SPIDER). The properties of the broadened spectrum and their modelling by numerical solution of a 1D nonlinear Schrodinger equation show that the main source of spectral broadening is self-phase modulation, whereas stimulated Raman scattering does not play a significant role. (C) 2018 Optical Society of America