Ringdown spectral photography

A new technique is presented which enables high-resolution cavity ringdown spectra to be obtained over a relatively large spectral region on microsecond timescales. The ringdown spectral photography (RSP) technique employs two key principles to simultaneously record the time and frequency response of the cavity along orthogonal axes of a two-dimensional array detector in a single-shot fashion. In these initial, proof-of-principle studies, the concepts employed in the RSP method are demonstrated and the fifth overtone spectrum of propane in the 635 nm region is measured.