Abstract

The ultrabroadband chirped mirrors [1] in combination with well-advanced spectral broadening technique open the door to the generation of mono-cycle laser pulses in the blue-visble-IR spectral range, will benefit the development of optical waveform and frequency-comb synthesizers. We report on a design and manufacturing of a complementary pair of ultrabroadband mirrors which has an average reflectivity of 87% in the wavelengths range 300-900 nm with residual group delay dispersion (GDD) ripples <100 fs². Their GDD and reflectivity is shown on Fig. 1. The mirror pair allows one to compensate a chirp of the corresponding spectrum (with a smooth phase), resulting in 2.2-fs pulses. To analyze the potential these mirrors offer for pulse compression and optical waveform synthesis, we have considered a hypothetical broadband dispersive delay line with 5 bounces off each of the two complementary chirped mirrors (total GDD is of the order of -200 fs² at 450 nm ) compensating the dispersion of 2 mm fused silica and 0.4 m of air. The measured GDD curve over the 400-900 nm range (limited by available white light interferometer) is in good correspondence with the design which is close to the target. We sent a Gaussian pulse carried at a wavelength of 450 nm (with a corresponding spectrum shown in inlet of Fig. 2) of duration of 1.8 fs (FWHM) through this optical delay line and calculated the temporal intensity profile of the pulse exiting the system. The results are summarized in Fig. 2.

© 2007 IEEE