Cavity ring-down in a fibre amplifier loop and combination with wavelength modulation spectroscopy [gas detection]

Assessed the suitability of a fibre cavity ring-down system for gas detection. Whilst relatively long ring-down times have been achieved, the sensitivity and stability of the system are not currently sufficient for monitoring the low gas concentrations of interest. We are therefore currently examining combining cavity ring-down with wavelength modulation spectroscopy and results are forthcoming.