Master thesis

Grueneisen relaxation photoacoustic microscopy with optical ultrasonic detection

This thesis was submitted at the physics department, Karl Franzens University of Graz, Austria, to achiev the degree Master of sience (M. Sc.).

License

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License

Author

• Franz Taffner

Supervisor

• Robert Nuster (Mag. Dr.rer.nat.)
• Günther Paltauf (Ao.Univ.-Prof. Mag. Dr.rer.nat.)

Abstract

In search of new contrast mechanisms, the Grueneisen relaxation photoacoustic microscopy (GR-PAM) emerged in the field of photoacoustic microscopy. In this thesis the underlaying effect, where the amplitude of the photoacoustic pressure wave changes due to a preheating, is proven. Furthermore, a comparison of GR-PAM to conventional optical resolution photoacoustic microscopy (OR-PAM) is done. Additionally, a compact version of an optical ultrasonic transducer, based on a Fabry–Pérot interferometer, is constructed and built.

Table of contents

1. Introduction
2. Principles of photoacoustics
   1. Photoacoustic effect
   2. Generation and propagation of photoacoustic waves
   3. Photoacoustic microscopy
3. Grueneisen relaxation photoacoustic microscopy (GR-PAM) theory
   1. The Grueneisen effect
   2. Dual pulse technique
   3. Resolution considerations
4. Experimental results of photoacoustic microscopy
   1. Proof of the Grueneisen effect
   2. Experimental results of GR-PAM
   3. Topographical analysis of OR-PAM images
5. Optical ultrasonic detection (OUSD)
   1. Principle of optical ultrasonic detection
   2. OUSD setup
   3. System development
   4. Cutoff frequency estimation
   5. Measuring-methods to determine the ultrasonic pressure
6. Experimental results of the optical ultrasonic detection system
   1. Finesse
   2. Transferfunction
7. Conclusion

• Appendix

Code base

Simulation of a photo acoustical signal excitation

Contact

franz.taffner@yahoo.de