We experimentally demonstrate large, widely tunable gain using Kerr instability amplification in MgO. By pumping the crystal near optical damage at 1.4 × 10 13 W / c m 2 by a femtosecond Ti:sapphire laser, we amplify visible and near-infrared pulses by factors > 5000 or a gain g ≈ 17 / m m . We temporally characterize the pulses to show that they are 42 fs in duration, much shorter than the pump pulse. In the non-collinear setup, the angle between the pump and seed selects the amplified wavelength, where we find certain angles amplify both the visible and near-infrared simultaneously. We find that near the maximum pumping intensities, higher-order nonlinearities may play a role in the amplification process.

Although gases, and more recently solids, have been used to create few-cycle pulses, we explore using liquid alcohols for spectral broadening and femtosecond pulse compression. By using a series of 1 cm cuvettes filled with 1-decanol, we have compressed a pulse from 83.6 fs down to 31.3 fs with a spectrum capable of supporting 25 fs pulses without filamentation. We measure the nonlinear index of refraction for various liquids, measuring n2 = (6.8 ± 0.5) × 10-20 m2/W for 1-decanol. We demonstrate liquids to be a compact, simple, versatile, and cost-effective material to obtain broad spectra.