Multispectral photoacoustic microscopy based on an optical–acoustic objective

AbstractWe have developed reflection-mode multispectral photoacoustic microscopy (PAM) based on a novel optical–acoustic objective that integrates a customized ultrasonic transducer and a commercial reflective microscope objective into one solid piece. This technical innovation provides zero chromatic aberration and convenient confocal alignment of the optical excitation and acoustic detection. With a wavelength-tunable optical-parametric-oscillator laser, we have demonstrated multispectral PAM over an ultrabroad spectral range of 270–1300nm. A near-constant lateral resolution of ∼2.8μm is achieved experimentally. Capitalizing on the consistent performance over the ultraviolet, visible, and near-infrared range, multispectral PAM enables label-free concurrent imaging of cell nucleus (DNA/RNA contrast at 270nm), blood vessel (hemoglobin contrast at 532nm), and sebaceous gland (lipid contrast at 1260nm) at the same spatial scale in a living mouse ear