Optimum Sample Thickness for Trace Analyte Detection with Field-Resolved Infrared Spectroscopy.

ABSTRACT: The strong absorption of liquid water in the infrared (IR) molecular fingerprint region constitutes a challenge for applications of vibrational spectroscopy in chemistry, biology, and medicine. While high-power IR laser sources enable the penetration of ever thicker aqueous samples, thereby mitigating the detrimental effects of strong attenuation on detection sensitivity, a basic advantage of heterodyne-measurement-based methods has-to the best of our knowledge-not been harnessed in broadband IR measurements to date. Here, employing field-resolved spectroscopy (FRS), we demonstrate in theory and experiment fundamental advantages of techniques whose signal-to-noise ratio (SNR) scales linearly with the electric field over those whose SNR scales linearly with radiation intensity, including co

SUBMITTER: Huber M 

PROVIDER: S-EPMC7304664 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature