Phase-shift feedback cavity ring-down spectroscopy

Phase shift cavity ring down absorption spectroscopy

Cavity ring down absorption spectroscopy with a continuous light souree is used to measure the transition frequencies and absolute absorption coefficient of the weak b ItCv' = 2) +--X I;-Cv" = 0) transition of 02. The absorption spectrum is extracted from a measurement of the magnitude of the phase shift that an intensity modulated continuous light beam experiences upon passing through an unsta...

Cavity-locked ring-down spectroscopy

Derivation of new equations for phase-shift cavity ring-down spectroscopy.

Current phase-shift cavity ring-down spectroscopy (PS-CRDS) experiments make use of equations originally developed for fluorescence studies. As these equations fail to take the length of the optical cavity and the superposition of reflecting beams into account, they lose validity as the length of the cavity increases. A new set of equations, based solely on the principles of PS-CRDS, is develop...

Phase-shift cavity ring-down spectroscopy on a microsphere resonator by Rayleigh backscattering

The optical ring-down time in a silica microsphere resonator is measured using phase-shift cavity ring-down spectroscopy. When detecting Rayleigh backscattered light that is coupled into the input waveguide it is found that the shift of the modulation phase angle, φ, is approximately linearly dependent on the amplitude modulation frequency. The microresonator therefore behaves as if it was a de...

Saturated-absorption cavity ring-down spectroscopy.

We report on a novel approach to cavity ring-down spectroscopy with the sample gas in saturated-absorption regime. This technique allows us to decouple and simultaneously retrieve the empty-cavity background and absorption signal, by means of a theoretical model that we developed and tested. The high sensitivity and frequency precision for spectroscopic applications are exploited to measure, fo...