Continuously tunable narrow-band operation of an injection-seeded ring-cavity optical parametric oscillator:...

A pulsed beta-barium borate optical parametric oscillator is injection seeded by cw diode lasers, yielding continuously tunable narrow-band output at its idler wavelength. A notable feature of this optical parametric oscillator is that it comprises a simple passive ring cavity with no active control of path length as the seed wavelength is scanned. We demonstrate this by recording Doppler-limited photoacoustic absorption spectra of acetylene gas and Doppler-free two-photon fluorescence spectra of rubidium vapor.