T.W. Tukker

Design, optimization, and characterization of a narrow-bandwidth optical parametric oscillator

The design, optimization, and performance of a narrow-bandwidth high-repetition-rate singly resonant picosecond optical parametric oscillator, based on a noncritical phase-matched lithium triborate crystal and synchronously pumped by the second harmonic of a mode-locked Nd:YLF laser, is described. The spectral bandwidth of the signal output is reduced with an intracavity birefringent filter to 0.06 nm. Furthermore, the filter allowed fast scanning of the output wavelength within the phase-matching bandwidth. A maximum average signal output of 1.6 W in pulses with a duration of 22 ps was obtained when the optical parametric oscillator was pumped four times above threshold with a 4-W pump source. With the present mirror set the signal and the idler wavelengths were tunable from, respectively, 740 to 930 nm and 1220 to 1830 nm. The total external power conversion efficiency was better than 55%.

A narrow-bandwidth optical parametric oscillator

A narrow-bandwidth, singly resonant, picosecond optical parametric oscillator based on a non-critical phase-matched lithium triborate crystal and synchronously pumped by the second-harmonic of a Nd:YLF laser mode-locked at 76 MHz is described. An intracavity birefringent filter reduces the spectral bandwidth and allows fast scanning of the output wavelength within the phase-matched bandwidth. A signal output of 1.6 W in Fourier transform limited pulses with a duration of 22 ps and a bandwidth of 0.06 nm has been obtained. The signal and idler wavelengths were tunable from 750 to 930 nm and from 1220 to 1770 nm, respectively.

Elliptical-focusing effect on parametric oscillation and downconversion

A theoretical study is presented that enables the calculation of the optimal focusing parameters in a singly resonant optical parametric oscillator and difference-frequency generation with elliptical foci. The effect of diffraction, phase matching, beam walk-off, and resonator astigmatism are included in the model. The results show that an optimal focusing configuration is obtained with unequal confocal beam parameters and that an elliptical beam profile can substantially increase the conversion efficiency when beam walk-off is present in the crystal.

Stimulated Raman gain scattering in planar dielectric waveguides

We have measured the vibrational Raman spectrum of a 1.2-microm-thick polystyrene film by using this film as an optical waveguide in a waveguide-stimulated Raman gain experiment. A gain factor of 1.3% was measured for the strong benzene mode at 1002 cm(-1). This value is in reasonable agreement with theoretical predictions.