Cavity ringdown laser absorption spectroscopy with a 1 kHz mid-infrared periodically poled lithium niobate optical parametric generator/optical parametric amplifier

A cavity ringdown spectrometer is described that employs a novel mid-infrared light source based on periodically poled lithium niobate. The source generates tunable light using the three-step process of optical parametric generation, spectral filtering, and optical parametric amplification. Its use allows for improvements over previous pulsed ringdown measurements including the ability to acquire data rapidly (at 1 kHz) over broad spectral regions (in principle, over the entire 2220–7690 cm−1 PPLN transparency window) with narrow linewidth (⩽0.08 cm−1). Data are presented that demonstrate performance and support its eventual use in a trace gas sensor.