Compact laser-diode-based optoacoustic mesoscopy.

Short-pulsed solid-state lasers (SSLs) are the most commonly employed light sources in optoacoustic imaging applications. However, their bulky size hinders compact and portable system implementations. Here we developed a compact laser diode (LD)-based optoacoustic mesoscopy (CoLD-OAM) scanner that employs a fiber-coupled laser diode source with 46 × 43 × 11 mm dimensions. CoLD-OAM features a scalable excitation pulse width in the 30-200 ns range, high pulse energies up to 6 µJ, and excellent pulse-to-pulse energy stability of 0.42%. Real-time imaging of the human wrist has been demonstrated with the system, achieving image quality similar to that of SSL-based systems. These advancements facilitate the development of portable optoacoustic systems with strong clinical translation and commercialization potential.