Microlaser-pumped periodically poled lithium niobate optical parametric generator–optical parametric amplifier

For what is believed to be the first time, a single-longitudinal-mode passively $Q$-switched Nd:YAG microlaser is used to pump a narrow-bandwidth periodically poled lithium niobate (PPLN) optical parametric generator–optical parametric amplifier (OPG–OPA). Before amplification in the OPA, the output of the OPG stage was spectrally filtered with an air-spaced etalon, resulting in spectroscopically useful radiation (bandwidth, $\sim 0.05 {\mathrm{cm}}^{-1}$ FWHM) that was tunable in $15‐{\mathrm{cm}}^{-1}$ segments anywhere in the signal range $6820–6220 {\mathrm{cm}}^{-1}$ and the idler range $2580–3180 {\mathrm{cm}}^{-1}$. The ability to pump an OPG–OPA with compact, high-repetition-rate, intrinsically narrow-bandwidth microlasers is made possible by the high gain of PPLN. The result is a tunable light source that is well suited for use in portable spectroscopic gas sensors.