基于声光偏转的高速GHz超快激光扫描技术  

High-Speed Scanning of GHz Ultrafast Laser Using Acousto-Optic Deflection

作　　者：张静 温俊鹏[1,2] 朱喆 韦小明 杨中民 Zhang Jing;Wen Junpeng;Zhu Zhe;Wei Xiaoming;Yang Zhongmin(School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510640,Guangdong,China;State Key Laboratory of Luminescent Materials and Devices,South China University of Technology,Guangzhou 510640,Guangdong,China;Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices,South China University of Technology,Guangzhou 510640,Guangdong,China;Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques,South China University of Technology,Guangzhou 510640,Guangdong,China;Research Institute of Future Technology,South China Normal University,Guangzhou 510006,Guangdong,China)

机构地区：[1]华南理工大学物理与光电学院,广东广州510640 [2]华南理工大学发光材料与器件国家重点实验室,广东广州510640 [3]华南理工大学广东省特种光纤材料与器件工程技术研究开发中心,广东广州510640 [4]华南理工大学广东省光纤激光材料及应用技术重点实验室,广东广州510640 [5]华南师范大学未来技术研究院,广东广州510006

出　　处：《光学学报》2023年第23期225-232,共8页Acta Optica Sinica

基　　金：国家自然科学基金重大科研仪器研制项目(61927816);广东省珠江人才引进创新团队项目(2021ZT09Z109);广东省自然科学基金(2021B1515020074);广东省科技计划(2020B1212060002);中德交流项目(M-0296)。

摘　　要：双光子激发显微镜是研究脑神经元活动的重要工具。基于传统机械式逐点激光扫描技术的双光子激发显微镜成像速度较慢,无法进行脑神经元活动的实时观察研究。此外,高速双光子激发显微成像需要配置高重复频率飞秒激光,以保证在较短的像素停留时间内获得较高的信息强度。本文提出了基于声光偏转的并行GHz超快激光扫描技术,通过设计射频编码方案,在920 nm波段搭建了高速GHz超快激光扫描系统。通过调整时间和空间重合,最终在15~31 MHz频率范围内获得了33个可分辨的并行GHz超快激光扫描光束,为实现高速双光子激发显微成像提供了技术支撑。Objective Two-photon excitation microscopy is a powerful tool for studying brain neuronal activities.The imaging speed of traditional two-photon excitation microscopy technologies based on mechanical point-by-point laser scanning is relatively slow,which prevents the real-time observation of neuronal activities.Additionally,femtosecond lasers with high repetition rate are essential for high-speed two-photon excitation microscopy to achieve high signal intensity within a short pixel dwell time.We demonstrate a parallel GHz ultrafast laser scanning technology using acousto-optic deflection to exploit new potential for high-speed two-photon microscopy.The high-speed GHz ultrafast laser scanning system is built in the 920 nm wavelength range.By adjusting the temporal and spatial arrangement,33 distinguishable parallel GHz ultrafast laser scanning beams are simultaneously generated within a frequency range of 15-31 MHz.Methods We adopt high-speed single-pixel parallel signal detection.The 920-nm femtosecond laser with a high repetition rate is split into two polarized beams using a polarizing beam splitter.One beam experiencing multitone-frequency modulation via an acousto-optic modulator serves as the reference beam,and the other beam is deflected by the radio frequency(RF)encoding technology.A time-domain signal with a random initial phase for each frequency drives the acousto-optic deflector to generate a one-dimensional laser beam array.The light spot is characterized by a CCD camera,then a delay line is employed to adjust the spatio-temporal overlap of the two beams to achieve interference.The electrical signals generated by the photodetector are digitally sampled by a high-speed data acquisition card and then are applied with a fast Fourier transform(FFT).Each laser beam is tagged with a specific frequency.Results and Discussions Frequency encoding design is performed within an RF range of 55-71 MHz to generate multitone RF driving signals with 33 frequencies,and each with a random initial phase.The duration of

关 键 词：双光子显微成像 声光偏转 高速激光扫描 飞秒激光 

分 类 号：O439[机械工程—光学工程]