One in a Trillion: Exploring Spectroscopic Limits of Detection with TOPTICA’s cw OPO

Direct tunable laser absorption spectroscopy fails to detect weakly absorbing molecules, where the absorption coefficient is below 10-4 cm-1. Several advanced spectroscopic techniques have taken advantage of laser frequency manipulation and stabilization to reduce the limit of detection down to 10-12 cm-1 or lower. These techniques have mostly been applied to wavelength regimes where direct sources of emission are widely available (e.g. diode lasers in the NIR). In this presentation, we will show how one can implement these techniques with a light source based on nonlinear frequency conversion, TOPTICA’s cw OPO. This new light source provides access to 2.2 – 4 µm (2500 – 4500cm-1), a spectral region containing many important fundamental molecular stretch vibrations.