Abstract

The crossed-beam thermal lens technique is used to probe weak optical absorbance and small variations in thermal diffusivity within a probe volume of a few cubic micrometers. By recording the signal as the sample is translated through the probe volume, a high spatial resolution image may be generated based on either the absorbance or thermal diffusion of the sample. Furthermore, use of an appropriate mask in the probe beam profile allows identification and study of interfaces between media with different thermal-optical properties. The photothermal microscope has been used to study both geological and histological samples. Fluid inclusions within mineral samples and localized bacteriological infections within human tissue samples have been imaged.

© 1986 Optical Society of America