Photoacoustic guided wavefront shaping using digital micromirror devices

In recent years, wavefront shaping technology has made it possible to refocus scattered photons through turbid media. The utilization of photoacoustic signal as feedback for wavefront shaping offers non-invasive and deeppenetrating advantages, making it increasingly attractive in the field of biomedical research. However, due to the short decorrelation time of scattered light in living biological tissues, demonstrating the technique in vivo remains challenging. Digital Micromirror Devices (DMD) with their various modulation modes and high refresh rates hold great potential in addressing this challenge and have been widely employed in Photoacoustic Guided Wavefront Shaping (PAWS) applications. This paper presents the fundamental principles of using photoacoustic signal as feedback to guide wavefront shaping and highlights the advantages of PAWS in biological tissue imaging. Furthermore, a comparative analysis of three commonly used spatial light modulators in PAWS is provided, along with an overview of the three main techniques employed in wavefront shaping. Additionally, methods for improving the signal-to-noise ratio and imaging resolution in PAWS are summarized, followed by a discussion on potential future directions for this field.