795 nm大功率外腔半导体激光器的研究  

Research on 795 nm High Power External Cavity Semiconductor Laser

作　　者：张薇 仲莉[1] 张德帅 吴霞[1] 倪羽茜 刘素平[1] 马骁宇[1] Zhang Wei;Zhong Li;Zhang Deshuai;Wu Xia;Ni Yuxi;Liu Suping;Ma Xiaoyu(National Engineering Research Center for Optoelectronic Devices,Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China;College of Materials Science and Opto-Electronic Technology,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院半导体研究所光电子器件国家工程研究中心,北京100083 [2]中国科学院大学材料科学与光电技术学院,北京100049

出　　处：《光学学报》2023年第10期181-186,共6页Acta Optica Sinica

摘　　要：采用超极化惰性气体的磁共振成像技术可大大提高肺部影像成像质量,其中自旋交换光泵作为超极化惰性气体的关键,通常是对碱金属铷进行泵浦,为获得较好的泵浦效率,要求泵浦源具有窄光谱宽度和高功率的特点。针对这一需求,提出以体布拉格光栅(VBG)作为外腔反馈元件的795 nm窄谱宽外腔半导体激光器设计,并对VBG的外腔锁模稳定性进行了分析讨论,最终实现了功率为6.36 W,谱宽低至0.036 nm的795.245 nm单管外腔激光输出,为实现大功率的单管外腔半导体激光器奠定基础。Objective Compared with traditional techniques,magnetic resonance imaging using hyperpolarized inert gas as the contrast agent has greatly improved the quality of lung images.The hyperpolarized inert gas is obtained by means of spinexchange optical pumping,and pumping the alkali metal rubidium is the key to this process.However,the bandwidth of commercial high-power semiconductor lasers is wide,while the Doppler broadening linewidth of alkali metal atoms is narrow,which leads to low pumping efficiency.To match the pump spectrum width and atomic absorption spectrum width,researchers mainly use the surface grating or volume Bragg grating(VBG)as an external cavity feedback element to develop external cavity semiconductor lasers.In this way,the spectrum width can be narrowed,and the pumping efficiency can be improved to a certain extent.In the existing reports,however,few studies have realized the simultaneous output of lasers with narrow spectrum width and high power.Moreover,under the high power demand,most studies use the laser bar as the internal gain chip,which is exposed to problems such as poor beam quality and great coupling difficulty.Therefore,this work proposes an external cavity semiconductor laser based on a single-tube gain chip.The output performance of the laser can satisfy the narrow spectrum width and have high power in the meanwhile.Methods VBGs have the characteristics of a high damage threshold and polarization insensitivity.Therefore,this study uses a VBG as the external cavity feedback element and designs the external cavity structure given the performance characteristics of the element.The diffraction efficiency of the VBG is affected by the incident wavelength and the angle of the incident light.According to the diffraction efficiency diagram of the VBG(Fig.2),a single-tube semiconductor laser with a suitable wavelength is selected as the gain chip.Meanwhile,the front cavity surface of the gain chip can resist reflection after treatment to suppress the influence of the internal cavity mode,an

关 键 词：激光器 外腔半导体激光器 体布拉格光栅 窄谱宽 锁模 

分 类 号：TN248.[电子电信—物理电子学]