Doppler-Free Nonlinear Absorption in Ethylene by Use of Continuous-Wave Cavity Ringdown Spectroscopy
C R. Bucher, K K. Lehmann, David F. Plusquellic, Gerald T. Fraser
We report the first systematic study of Doppler-free, nonlinear absorption using cavity ring-down spectroscopy. We have developed a variant of cavity ring-down spectroscopy for the mid-infrared region between 9-11 m exploiting the intracavity power buildup that is possible using continuous wave lasers. The light source consists of a continuous wave CO2 laser with 1 mW of tunable infrared sidebands and couples into a high finesse stable resonator. The cavity is filled with a mixture of 0.5% ethylene (C2H4) in He (by volume) at a total pressure of 1.3 Pa. We tune the sideband frequencies to observe a saturated, Doppler-free Lamb dip in the υ7, 111,10 112,10 rovibrational transition of ethylene (C2H4) centered at 949.2 cm -1 . Power studies on the Lamb dip are presented to understand the effect of saturation on the Lamb dip linewidth, the peak depth and the broadband absorption.
, Lehmann, K.
, Plusquellic, D.
and Fraser, G.
Doppler-Free Nonlinear Absorption in Ethylene by Use of Continuous-Wave Cavity Ringdown Spectroscopy, Applied Optics
(Accessed March 2, 2024)