High-Resolution Photothermal Laser Probe

Abstract

An advance in pbotothermal imaging is described. A photothermal laser probe is presented that operates at a frequency of 1 GHz. At this frequency the spacial resolution is limited only by the optical spot size of the probe beam. The photothermal sensitivity of the probe is 1.2 × 10–4 degrees celsius with a 5-mW probe beam and a 1Hz bandwidth. The theoretical basis for the photothermal sensitivity will be presented along with an experimental description and verification of the theory. High-resolution photothermal images of implanted silicon will also be presented. Copyright © 1985 by The Institute of Electrical and Electronics Engineers, Inc.