All-diode-laser ultra-violet absorption spectroscopy and temporal gas correlation spectroscopy

Here, we present a scheme producing UV radiation around 302 nm by sum-frequency generation in beta-barium borate employing a blue and a near-infrared diode laser. The diode-laser-based spectrometer has a mode-hop-free tuning range of 50 GHz and can be used for high-resolution spectroscopic detection of sulfur dioxide. Differential measurements of several sulfur dioxide gas concentrations, at low pressure as well as at ambient atmospheric pressure, are demonstrated. A particularly interesting aspect of the mixing scheme, is that the near-infrared and blue radiation can be tuned to absorption features of water and nitrogen dioxide, respectively.