Abstract

We present a thorough analysis of the signal line shapes of Fourier-transform-based noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS). We discuss the signal dependence on the ratio of the modulation frequency, $f_m$, to the molecular linewidth, $\mathrm{\Gamma }$. We compare a full model of the signals and a simplified absorption-like analytical model that has high accuracy for low $f_m/\mathrm{\Gamma }$ ratios and is much faster to compute. We verify the theory experimentally by measuring and fitting the NICE-OFCS spectra of ${\mathrm{CO}}_2$ at 1575 nm using a system based on an Er:fiber femtosecond laser and a cavity with a finesse of $\sim 11000$.

© 2017 Optical Society of America

Wavelength-modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy signal line shapes in the Doppler limit

Aleksandra Foltynowicz, Weiguang Ma, Florian M. Schmidt, and Ove Axner
J. Opt. Soc. Am. B 26(7) 1384-1394 (2009)

Measurement of pressure-broadened, ultraweak transitions with noise-immune cavity-enhanced optical heterodyne molecular spectroscopy

Nicola J. van Leeuwen and Andrew C. Wilson
J. Opt. Soc. Am. B 21(10) 1713-1721 (2004)

Use of etalon-immune distances to reduce the influence of background signals in frequency-modulation spectroscopy and noise-immune cavity-enhanced optical heterodyne molecular spectroscopy

Patrick Ehlers, Alexandra C. Johansson, Isak Silander, Aleksandra Foltynowicz, and Ove Axner
J. Opt. Soc. Am. B 31(12) 2938-2945 (2014)

Doppler-broadened noise-immune cavity-enhanced optical heterodyne molecular spectrometry signals from optically saturated transitions under low pressure conditions

Aleksandra Foltynowicz, Weiguang Ma, Florian M. Schmidt, and Ove Axner
J. Opt. Soc. Am. B 25(7) 1156-1165 (2008)

Doppler broadened noise-immune cavity-enhanced optical heterodyne molecular spectrometry: optimum modulation and demodulation conditions, cavity length, and modulation order

Patrick Ehlers, Isak Silander, and Ove Axner
J. Opt. Soc. Am. B 31(9) 2051-2060 (2014)