Optical Parametric Amplification of Mid-Infrared Few-Cycle Pulses

We describe Ti:Sapphire pumped optical parametric amplification of carrier-envelope phase stabilized few-cycle ($<10$fs) mid-infrared pulses in type I $\beta$-barium borate. Experimental measurements show a $\times3.5$ amplification factor (from 100$\mu$J to 350$\mu$J) of the octave spanning spectrum ($1.1-2.4$$\mu$m) using a pump beam with 2.3mJ energy, 30fs duration and central wavelength of 800nm, corresponding to an energy extraction efficiency of $11\%$. Numerical simulations suggest potential amplification to 4.25mJ energy and temporal compression to a pulse duration of 7.3fs is possible with a pump energy of 30mJ and duration of 30fs in a 25mm diameter, 1.5mm thick BBO crystal.