Chandran A M, Runcorn T H, Murray R T, Taylor J R
Opt Lett. 2019 Dec 15;44(24):6025-6028. doi: 10.1364/OL.44.006025.
We demonstrate a nanosecond pulsed source at 620 nm with watt-level average power by frequency-doubling a 1240 nm phosphosilicate Raman fiber amplifier. A gain-switched laser diode operating at 1064 nm is amplified in an ytterbium fiber master oscillator power amplifier system and then converted to 1240 nm using a phosphosilicate Raman fiber amplifier with a conversion efficiency of up to 66%. The Raman fiber amplifier is seeded with a continuous-wave 1240 nm laser diode to obtain narrow-linewidth radiation, which is subsequently frequency-doubled in a periodically poled lithium tantalate crystal. A maximum average power of 1.5 W is generated at 620 nm, corresponding to a pulse energy of 300 nJ at a repetition rate of 5 MHz. The source has excellent beam quality (≤1.16) and an optical efficiency (1064 nm to 620 nm) of 20%, demonstrating an effective architecture for generating red pulsed light for biomedical imaging applications.
我们通过对1240nm磷硅酸盐拉曼光纤放大器进行倍频，展示了一种平均功率为瓦级的620nm纳秒脉冲源。一个工作在1064nm的增益开关激光二极管在镱光纤主振荡功率放大器系统中被放大，然后使用转换效率高达66%的磷硅酸盐拉曼光纤放大器转换为1240nm。拉曼光纤放大器由一个连续波1240nm激光二极管注入种子光以获得窄线宽辐射，随后在周期性极化钽酸锂晶体中进行倍频。在620nm处产生了1.5W的最大平均功率，对应于5MHz重复频率下300nJ的脉冲能量。该光源具有优异的光束质量（≤1.16）和20%的光学效率（从1064nm到620nm），展示了一种用于生物医学成像应用中产生红色脉冲光的有效架构。
