Previous research on achieving the alignment of compression gratings has mainly focused on the parallelism of the gratings. We propose a promising method to achieve parallelism and especially accurately adjust the grating to its optimum working angle to achieve dispersion compensation. A spectrometer and a precisely adjustable mirror pair are cooperatively used to measure the wavelength of the light diffracted by the grating, satisfying the Littrow condition. Meanwhile, the tiny slit of the spectrometer can decrease the grating-tip and in-plane rotation error during the alignment procedure. Using this technique, the residual phase of the compressed pulse is optimized and the compressed pulse duration is 25.4 fs, which is 1.06 times that of the Fourier-transform-limited compressed pulse.
We report a generation of 10.6% conversion efficiency near 1053 nm first order Stokes pulse in stimulated Raman
scattering pumped using 800 nm Ti:sapphire based femtosecond pulses that are stretched to 460 ps, obtained by use of a
single pass ethonal Raman shifter. The Stokes pulse almost maintains the bandwidth of the pump and is compressed to
~10 ps using a mismatched grating-pair. The spectral characteristic of the Raman pulse is calculated and the results
explain the observed transient features.
We demonstrate high amplified spontaneous emission (ASE) contrast pulses in a Nd:glass laser system based on the hybrid double chirped pulse amplification (double CPA) scheme. By an OPA temporal cleaning device, ~100 uJ/46 fs/ 1011 clean pulses are generated and amplified in the next Nd:glass laser. After compressor, >150 mJ/~0.5 ps/1 Hz pulses can be obtained. The ASE temporal contrast of amplified pulses is ~1011 with energy gain ~2.5×104 in the Nd:glass amplifiers.
Comb-like supercontinuum generation is investigated with dual-pulse filamentation in air. The period of spectral
fringes varies with the time delay between collinearly propagating pulses. The comb-like supercontinuum may be a
potential tool for optical remote sensing.