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

24-Jun-20

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

English

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

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