High resolution ultrasound and photoacoustic images of stained neutrophils, lymphocytes and
monocytes from a blood smear were acquired using a combined acoustic/photoacoustic microscope.
Photoacoustic images were created using a pulsed 532 nm laser that was coupled to a single mode fiber to
produce output wavelengths from 532 nm to 620 nm via stimulated Raman scattering. The excitation
wavelength was selected using optical filters and focused onto the sample using a 20 objective. A
1000 MHz transducer was co-aligned with the laser spot and used for ultrasound and photoacoustic
images, enabling micrometer resolution with both modalities. The different cell types could be easily
identified due to variations in contrast within the acoustic and photoacoustic images. This technique
provides a new way of probing leukocyte structure with potential applications towards detecting cellular
abnormalities and diseased cells at the single cell level.