Design and application of 500 nm bandwidth chirped mirror pair

A chirped dielectric multilayer mirror pair with controlled dispersion in the wavelength range 600 nm~1100 nm with 825 nm centre wavelength was designed and fabricated. The group delay dispersion of the mirror pair is about -100 fs2. The reflectivity of the mirror is 99% and the theoretical group delay dispersion ripple is less than 50 fs2 in the working spectral range. The mirror pair was used to compensate the 10.3 fs ultra-short pulse passed through 0.5 mm lithium triborate (LBO) crystal and the frequency-resolved optical gating technique was used to measure pulse,then the 10.3 fs pulse was broadened to 39.6 fs due to the dispersion of LBO crystal.Experimental results show that the full width at half summit is 11.6fs after one bounce dispersion compensation of the chirped mirror pair;and the broaden pulse is compressed to 10.7 fs by using two bounces dispersion compensation.