Cavity ring-down spectroscopy measurements of resonance-enhanced two-photon absorption by n2o

Hodges, Joseph T.

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https://hdl.handle.net/2142/107485 Copy

Description

Title

Cavity ring-down spectroscopy measurements of resonance-enhanced two-photon absorption by n2o

Author(s)

Hodges, Joseph T.

Contributor(s)

• Lehmann, Kevin
• Bailey, D. Michelle
• Fleisher, Adam J.
• Zhao, Gang

Issue Date

2020-06-24

Keyword(s)

Comparing theory and experiment

Abstract

As recently discussed by K.K. Lehmann in a theoretical analysis of two-photon absorption (TPA) [1], the combination of high circulating power and counterpropagating fields associated with the cavity ring-down spectroscopy (CRDS) technique can yield relatively prominent, two-photon, Doppler-free absorption features for near-resonant, three-level rovibrational systems. Here, we present CRDS measurements of TPA by N$_2$O near $\lambda$ =4.5 $\mu$m. The experiment comprises a quantum cascade laser which is frequency-coupled to a high-finesse optical resonator through controlled optical feedback. Consistent with Lehmann's model, we observe CRDS decay signals that depend upon two characteristic decay rates: a constant single-photon value and an intracavity-power-dependent two-photon absorption rate. The resulting spectra exhibit strong Doppler-free features, saturation effects at low pressure, and TPA cross-section and collisional broadening coefficient consistent with theoretical predictions. 1. K.K. Lehmann, "Resonance enhanced two-photon cavity ring-down spectroscopy of vibrational overtone bands: A proposal," J Chem Phys \textbf{151}, 144201 (2019).

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/107485

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Copyright 2020 is held by the Author(s)

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