Refining Photothermal Deflection Spectroscopy: Incorporating Reflectance for Enhanced Accuracy in Light‐Absorption Measurements

Abstract

We investigate a method for measuring light absorption using photothermal deflection spectroscopy (PDS). Typical reflectance and transmittance (R&T) absorption measurements have low spectral resolution with standard setups. We believe that absorption measurements using PDS solve this problem because of its high sensitivity, even at a high spectral resolution. However, accurate absorption measurements have not been obtained using conventional PDS. The reflectance of the sample must be considered in the absorptance calculations. We compare various absorption measurement methods and propose a novel calculation method for accurate PDS absorption measurements. We fabricate a sample with quantum structures and perform PDS measurements. Exciton absorption peaks are also observed. We demonstrate the high spectral resolution of PDS and confirm the measured exciton absorption peaks using piezoelectric photothermal measurements. Furthermore, we confirm that the absolute values of absorptance derived from the R&T and PDS measurements agree well. Our new PDS absorption measurement technique enabled us to obtain accurate absorption characteristics, which are indispensable for designing and optimizing optoelectronic devices.This article is protected by copyright. All rights reserved.