MODELING OF A PHOTOACOUSTIC PROBE DESIGNED FOR MEDICAL APPLICATIONS

A model is presented describing the thermoelastic photoacoustic intera ction in a layered medium within a transparent fluid, where a polymer transducer is used for the detection of ultrasonic pulses. By taking t he optical absorption coefficient and finite layer thickness into acco unt, the amplitude and shape of photoacoustic transients are calculate d for both forward and backward travelling directions. Additionally, p hotoacoustic transient interaction with the PVDF transducer has been c haracterised using a discrete-time algorithm for the transducer respon se. Good agreement with experimental waveforms are demonstrated, so th at this may form the basis of system characterisation when miniature l aser-ultrasound probes are used in various applications.