Automated Laser-Fiber Coupling Module for Optical-Resolution Photoacoustic Microscopy

• Published in: Sensors (Basel, Switzerland) Switzerland), 2023-07, Vol.23 (14), p.6643
• Main Authors: Han, Seongyi, Kye, Hyunjun, Kim, Chang-Seok, Kim, Tae-Kyoung, Yoo, Jinwoo, Kim, Jeesu
• Format: Article
• Language: English
• Subjects: Acoustics; Automation; Contrast agents; Efficiency; Fiber optics; Hemoglobin; Imaging systems; laser delivery; laser-fiber coupling; Lasers; Light; Microelectromechanical systems; Microscope and microscopy; Microscopy; optical fiber; Optimization; photoacoustic microscopy; Signal processing; Software; Tissues; Ultrasonic imaging; Ultrasonic transducers
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23146643

Photoacoustic imaging has emerged as a promising biomedical imaging technique that enables visualization of the optical absorption characteristics of biological tissues in vivo. Among the different photoacoustic imaging system configurations, optical-resolution photoacoustic microscopy stands out by providing high spatial resolution using a tightly focused laser beam, which is typically transmitted through optical fibers. Achieving high-quality images depends significantly on optical fluence, which is directly proportional to the signal-to-noise ratio. Hence, optimizing the laser-fiber coupling is critical. Conventional coupling systems require manual adjustment of the optical path to direct the laser beam into the fiber, which is a repetitive and time-consuming process. In this study, we propose an automated laser-fiber coupling module that optimizes laser delivery and minimizes the need for manual intervention. By incorporating a motor-mounted mirror holder and proportional derivative control, we successfully achieved efficient and robust laser delivery. The performance of the proposed system was evaluated using a leaf-skeleton phantom in vitro and a human finger in vivo, resulting in high-quality photoacoustic images. This innovation has the potential to significantly enhance the quality and efficiency of optical-resolution photoacoustic microscopy.