Application of the BaTiO3 Beam Fanning Limiter as an Adaptive Spatial Filter for Signal Enhancementin Pulsed Laser Excited Photothermal Spectroscopy

Document Type

Article

Journal/Book Title

Optics Letters

Publication Date

1989

Volume

14

First Page

1020

Abstract

A method for obtaining a high-contrast visible-light signal from infrared absorption in low-absorbance samples is described. This method is based on a beam-fanning optical limiter in photorefractive BaTiO3. The resulting signal is not linear but does exhibit an enhanced signal-to-background ratio that is 4 to 6 orders of magnitude better than that of conventional infrared absorption spectrophotometry in the shot-noise limit. A simple model for the beam-fanning, optical-limiter-based, pulsed-laser-excited photothermal spectroscopy detector is found to describe the experimental data adequately. This technique using photothermal spectroscopy detection may have advantages for rapid signal analysis and for two-dimensional visible imaging of infrared absorption.

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