基于单纵模纳秒脉冲激光的光学分辨率光声显微成像  

Optical Resolution Photoacoustic Microscopy Based on Single-longitudinal-mode Nanosecond Laser

作　　者：刘江波 李渊骥[1,2] 冯晋霞 张宽收[1,2] LIU Jiang-bo;LI Yuan-ji;FENG Jin-xia;ZHANG Kuan-shou(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学光电研究所,量子光学与光量子器件国家重点实验室,山西太原030006 [2]山西大学,极端光学协同创新中心,山西太原030006

出　　处：《量子光学学报》2022年第1期71-78,共8页Journal of Quantum Optics

基　　金：国家自然科学基金(62175135)。

摘　　要：本文设计并搭建了一套激励光和超声探测器对向共轴共焦的具备亚细胞尺度成像分辨率和毫米级成像深度的光学分辨率光声显微成像(OR-PAM:Optical-resolution photoacoustic microscopy)系统。与基于多纵模脉冲激光激励的光声成像系统相比,使用自制的单纵模纳秒532 nm脉冲激励光源,将光声探测的信号强度提高了1.35倍,测得成像系统的轴向分辨率为18μm,横向分辨率为8μm,成像深度为1.54 mm,成像深度-横向空间分辨率比达192.5。利用研制的OR-PAM系统对嵌有碳纤维丝的仿体样品以及活体小鼠的耳朵进行成像,获得了高分辨率的图像。Optical resolution photoacoustic microscopy(OR-PAM), benefiting from rich optical contrast, scalable acoustic resolution, and deep penetration depth, is a rapidly developing biomedical imaging technology in recent years. To meet the need of shallow cells imaging in large-scale living organisms, an OR-PAM system with subcellular level imaging resolution and more than one millimeter imaging depth was designed and constructed in this paper. In the OR-PAM system, a homemade single longitudinal mode(SLM) nanosecond(ns) 532 nm pulse laser was adopted as excitation source, and an ultrasonic sensor with a center frequency of 50 MHz was adopted as the acoustic detector, noting that the excitation laser and the ultrasonic detector were coaxially mounted with a common focus. Two-dimensional(2D) and three-dimensional(3D) images was obtained based on a homemade program-controlled 2D electric translation table, as well as an automatic signal acquisition and image reconstruction program. In a single point photoacoustic detection experiment using a agar block embedded with black tape as sample, the signal-to-noise ratio(SNR) of our OR-PAM was 1.35 times higher than that of a conventional OR-PAM system excited by a multi-longitudinal mode pulsed laser, owing to the low amplitude noise, less clutter and good beam quality of the self-made SLM 532 nm excitation laser.On this basis, the key performance index of the OR-PAM system was measured. The imaging depth of the system was determined by a series of single point photoacoustic detection with different excitation laser focus position, while the absorbers were 10 hairs placed at different depths in an imitation sample. Since the measured imaging depth was 1.54 mm, the axial and lateral resolutions of the OR-PAM system was determined using two samples embedded with a human hair and a sharp knife edge at the depth of1.54 mm, respectively. The measured photoacoustic signal of the human hair was copied and translated in time domain, and when the translated signal and the original signal

关 键 词：单纵模纳秒脉冲激光 光学分辨率 光声显微成像 亚细胞结构尺度 

分 类 号：TN249[电子电信—物理电子学]