Abstract

Spectroscopic studies of the absorption of light by pigments in lichen in situ have been hindered by the optical properties of the samples. Characteristic of many biological samples, the crustose lichen Acarospora schleicheri have a low reflectivity and high optical density. These properties make conventional transmittance spectroscopy and diffuse reflectance measurements difficult. Photoacoustic spectroscopy (PAS), however, is ideally suited for measuring the spectral characteristics of opaque and/or low reflecting samples.

© 1981 Optical Society of America