Ultrashort pulses in the infrared from synchronously pumped optical parametric oscillators

Two subjects are presented in this dissertation, the common theme being the development of ultrashort optical pulse-generation techniques: a continuous wave synchronously pumped and mode-locked optical parametric oscillator; and the use of the intracavity optical Kerr effect to enhance the performance of an actively mode-locked homogeneously broadened laser.;There is very large continuing interest in generating ultrashort optical pulses in the picosecond to femtosecond time range, tunable in the mid-infrared spectral region (1-5 ;The penultimate chapter details the use of the optical Kerr effect to enhance the performance of a conventional lamp-pumped and actively mode-locked Nd:YAG laser. Theories of mode locking in the presense of intracavity self-phase modulation are presented, from which a pulsewidth-reduction limit is predicted. Experimentally, this technique is applied to a commercial lamp-pumped and actively mode-locked Nd:YAG laser, and the reduction of pulsewidth by approximately a factor of two, with no loss of average power, is demonstrated; these results are reported in detail. Also illustrated is the bifurcation of the mode-locked pulses which occurs when an excessive amount of intracavity self-phase modulation is present.