Programmable chirp compensation for 6-fs pulse generation with a prism-pair-formed pulse shaper

We describe a TF5 prism-pair-formed pulse shaper for programmable pulse chi rp compensation. The advantages of this kind of pulse shaper are: 1) very b road bandwidth of transmission; 2) smaller losses; and 3) no requirement fo r a large-size spatial light modulator (SLM) if the input spectrum is very broad. In our experiment, an ultrabroad spectral (500-1000 nm) pulse is pro duced by launching 1-kHz, 30-fs, 400-mu J pulses at 780 nm into an argon-fi lled glass capillary fiber at the gas pressure of 2.0 bar. The fiber has an inner diameter of 140 mu m and a length of 60 cm, The chirped pulse is fir st precompressed by a pair of BK7 prisms with a separation length of 65 cm and then directed into the prism-pair-formed pulse-shaping apparatus with a 128-pixel SLM, which provides quadratic and cubic phase compensation. When the quadratic and cubic phases are -330 fs(2) and +2000 fs(3), respectivel y, at the wavelength of 760 nm, an ultrashort optical pulse of 6 fs (FWHM) is generated. This is, to the best of our knowledge, the shortest optical p ulse ever compressed using the SLM pulse-shaping technique.