HIGH-REPETITION-RATE FEMTOSECOND OPTICAL PARAMETRIC OSCILLATOR AMPLIFIER SYSTEM NEAR 3 MU-M

An ultrafast laser system for the chemically important 3-mu m spectral region has been constructed by means of noncritically phased-matched KTiOPO4 optical parametric gain elements. An optical parametric oscill ator, synchronously pumped by a mode-locked Ti:sapphire oscillator, ge nerates high-quality seed pulses for an optical parametric amplifier. The optical parametric amplifier, pumped by a high-repetition-rate Ti: sapphire regenerative amplifier, amplifies the seed pulses by a factor of 520. Pulses with an energy of 550 nJ and a pulse width of 160 fs a re produced at a 250-kHz repetition rate in the 3-mu m region.