Photothermal spectroscopy is a powerful tool to investigate the optical absorption and thermal characteristics of a
sample. The photo-thermal effect, that is the basis for photothermal spectroscopy, is the conversion of optical energy
into heat. Photothermal spectroscopy is implemented in a variety of methods. Biomedical imaging applications
commonly implement the Photo-Thermo-Acoustic (PTA) method, that is based on measuring the acoustic pressure wave
that propagates due to the photothermal effect, caused by absorption of energy from a heating laser.
This research demonstrates photothermal elastic displacement measurement using a coherent confocal microscope, as a
first step towered pothothermal spectroscopy. The high accuracy of the interferometer, that is the heart of the coherent
confocal microscope, in detecting small changes in position makes it intrinsically adequate to measure the thermoelastic
expansion of the sample that results from the photothermal process. In this research Polyvinyl-Chloride Plastisol (PVCP)
samples, constructed with different absorption coefficients, were tested using different heating light fluences. The results
are compared against an approximate theoretical model and are found to be in good agreement.
The Opto-Photo-Thermo-Elastic (Optical detection of elastic displacement changes due to the phototheraml process)
technique is demonstrated in this research as a first step toward extending the capability of confocal microscopes to
image deeper into tissues than is presently possible, and to detect new modes of contrast.