Cavity-ringdown molecular spectroscopy based on an optical frequency comb at 1.45-1.65 microm
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Updated: Jul 17, 2026

Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
Michael J Thorpe1, Darren D Hudson, Kevin D Moll
1JILA, National Institute of Standards and Technology, Boulder, Colorado 80309-0440, USA.
Abstract:
Optical frequency comb-based cavity-ringdown spectroscopy has recently enabled high-sensitivity absorption detection of molecules over a broad spectral range. We demonstrate an improved system based on a mode-locked erbium-doped fiber laser source centered at 1.5 microm, resulting in a spectrometer that is inexpensive, simple, and robust. It provides a very large spectral bandwidth (1.45-1.65 microm) for investigation of a wide variety of molecular absorptions. Strong molecular absorptions at 1.5 mum allow for detection at sensitivities approaching the 1 part in 10(9) volume level. We provide a detailed description of our spectrometer and present measurements of the rovibrational spectra for CO, NH3, and C2H2 with an absorption sensitivity of 2 x 10(-8) cm(-1)Hz(-1/2) per detection channel.
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