Miniaturized all-optical photoacoustic microscopy based on microelectromechanical systems mirror scanning.
ABSTRACT Achieving photoacoustic microscopic imaging through a miniaturized scanning head is a crucial step toward high-resolution photoacoustic endoscopy. In this work, we have developed a miniaturized probe head using a microelectromechanical systems (MEMS) based mirror for raster scan of the laser beam and our newly developed super broad bandwidth microring resonator based ultrasound detector for photoacoustic signal detection. Through this all-optical design, which offers unique advantages for endoscopic applications, this system is capable of three-dimensional (3D) imaging with high resolution of 17.5 μm in lateral direction and 20 μm in axial direction at a distance of 3.7 mm. After the performance of this system was validated through the experiments on printed grids and a resolution test target, microscopic imaging of the 3D microvasculatures in canine bladders was also conducted successfully, demonstrating the potential of novel photoacoustic endoscopic in future clinical management of bladder cancer.
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ABSTRACT: Detectors play a vital role in ultrasound sensing and imaging applications. With the rapid development of photoacoustic imaging technology in recent years, novel ultrasound detectors based on optical methods have gained increased attention, among which the imprinted polymer microring is a representative one. This review covers the device design, fabrication, and characterization, with an emphasis on how the imprinting-based fabrication methodology benefits the device performance, which further facilitates photoacoustic imaging and sensing applications. By carefully designing and fabricating the imprint mold, the imprinted polymer microring has a quality factor on the order of at 780 nm. The device has advantages such as wide acoustic bandwidth response from dc to 350 MHz at −3 dB, low noise equivalent detectable pressure, wide acceptance angle, and so on. The polymer microring has been successfully employed in applications such as photoacoustic imaging and real-time terahertz pulse detection.IEEE Sensors Journal 06/2015; 15(6):3241-3248. DOI:10.1109/JSEN.2015.2421519 · 1.85 Impact Factor
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ABSTRACT: It is beneficial to study tumor angiogenesis and microenvironments by imaging the microvasculature and cells at the same time. Photoacoustic microscopy (PAM) is capable of sensitive three-dimensional mapping of microvasculature, while fluorescence microscopy may be applied to assessment of tissue pathology. In this work, a fiber-optic based PAM and confocal fluorescence microscopy (CFM) dual-modality imaging system was designed and built, serving as a prototype of a miniaturized dual-modality imaging probe for endoscopic applications. As for the design, we employed miniature components, including a microelectromechanical systems (MEMS) scanner, a miniature objective lens, and a small size optical microring resonator as an acoustic detector. The system resolutions were calibrated as 8.8 μm in the lateral directions for both PAM and CFM, and 19 μm and 53 μm in the axial direction for PAM and CFM, respectively. Images of the animal bladders ex vivo were demonstrated to show the ability of the system in imaging not only microvasculature but also cellular structure.Conference on Photons Plus Ultrasound: Imaging and Sensing; 03/2014
Article: MEMS based Medical EndomicroscopesIEEE Journal of Selected Topics in Quantum Electronics 07/2015; 21(4):1-1. DOI:10.1109/JSTQE.2015.2389530 · 3.47 Impact Factor