Novel Optical-resolution Photoacoustic Microscopy System Developed

Researchers from the California Institute of Technology have developed a two-dimensional (2D) MFOR-PAM system utilizing a 2D microlens array for optical excitation and an acoustic ergodic relay to simultaneously detect the PA responses to the multifocal optical illuminations with a single-element ultrasonic transducer. Their paper was published in Light: Science & Applications. 

The system—currently referred to as multifocal optical-resolution photoacoustic microscopy through an ergodic relay (MFOR-PAMER)— shortens scanning time by at least 400 times when compared to conventional optical-resolution photoacoustic microscopy (OR-PAM) systems, according to researchers. 

The functionality of the system is centered around acoustic ergodic relay (ER). For PA imaging, an ergodic relay is used as an encoder to transform the PA signals from different inputs into unique temporal signals. “By combining the microlens array with the ergodic relay, we can improve the acoustically defined image resolution of the system to the optically defined image resolution, and improve the imaging speed by a factor equal to the number of microlens elements," says lead researcher Lihong Wang. 

"Our MFOR-PAMER system has promising potential for many biomedical applications, such as utilizing ultra-violet (UV) illumination for the high-speed, label-free histological study of biological tissues. This design can reduce the imaging time from several hours (with a conventional UV OR-PAM system) to less than a minute, significantly improving the efficiency of clinical histology and diagnostics,” they conclude.