  We demonstrate surface acoustic waves inside polystyrene microspheres of
different sizes experimentally through photoacoustic microscopy and validate
the experimental result with simulation. A novel method for sample preparation
of a lifted sample is also presented where the microparticles are suspended in
agarose above the surface of the petridish. Another objective of this study was
to investigate the results with different laser focus hitting on the
microparticles and their impact on photoacoustic images and photoacoustic
signals. An absorbing microsphere is excited with a pulsed laser of wavelength
532 nm and the photoacoustic signal is detected using a 40 MHz transducer. On
analyzing the photoacoustic signals from microspheres, we find the signature of
surface acoustic waves.
