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Description
Photoacoustic microscopy is an imaging technique mainly applied to biological tissue, using short laser pulses to excite acoustic signals in optically absorbing structures. The standard approach in photoacoustic microscopy is the time-resolved detection of the generated sound waves using a single-element ultrasound detector. This has the advantage that, ideally, these sensors are acoustically focused and aligned confocally with the optical focus, thereby achieving high sensitivities. The 3D dataset for image generation is obtained from the recorded ultrasonic depth profiles at various lateral positions on the sample surface. However, to maintain the advantage of high sensitivity in imaging with a large field of view, it is necessary to scan the sample relative to the fixed arrangement of the excitation laser spot and the acoustic focus, which results in reduced imaging speed. This can be addressed, for example, through parallelization using multiple ultrasound sensors simultaneously.This work demonstrates ways in which this parallelization of ultrasound detection using an optical camera can be implemented for application in photoacoustic microscopy. Depending on the specific experimental setup, cross-sectional images or projections of the generated ultrasound field at a specific time can thus be efficiently recorded. In combination with structured optical excitation, such as focused multipoint or multiline excitation as well as coded pattern excitation, a variety of possibilities arise, which are presented in this work using simulations and discussed in terms of their advantages and disadvantages. In addition, results from proof-of-principle experiments are shown that were obtained using the camera-based ultrasonic detection projection method in combination with line-pattern excitation for photoacoustic microscopy.