Supercontinuum source as a probing beam in photoreflectance and photoacoustic spectroscopy

Abstract

In this paper we show a proof of concept for the application of the supercontinuum light source as a probing beam in photoreflectance (PR) and photoacoustic (PA) spectroscopies. We have observed that the signal-to-noise ratio in PR measurements is about one order of magnitude worse when the supercontinuum is applied as the probing beam instead of the quartz tungsten halogen (QTH) lamp, which is a typical light source for PR measurements. When the PR signal is relatively strong (ΔR/R ≥ 10−4) measurements with no significant loss in spectral details can be obtained. It means that the supercontinuum light source has promising perspectives in the application in PR spectroscopy especially that with this light source it is easy: i) to eliminate the unwanted photoluminescence signal, ii) to increase the distance between the sample and the optical elements of the experimental setup, and iii) to improve the spatial resolution in PR measurements. Moreover, it is shown that the supercontinuum can be applied in PA spectroscopy. In this case we did not observe any significant differences in the signal-to-noise ratio for measurements with supercontinuum and QTH lamp.