Tan Sisi, Yang Lingxiao, Wei Xiaoming, Li Can, Chen Nan, Tsia Kevin K, Wong Kenneth K Y
Opt Lett. 2017 Apr 15;42(8):1540-1543. doi: 10.1364/OL.42.001540.
We report a high-speed wavelength-swept source operating at 2.0 μm through advanced time-stretch technology. It sweeps over 30 nm at a speed of 3.3×10 nm/s and a repetition rate of ∼19 MHz. To the best of our knowledge, this is the first time that a megahertz-stable swept source has been implemented at such a long wavelength. A wide bandwidth is enabled by a simple mode-locked fiber laser that covers a wavelength range of ∼60 nm. The all-optical wavelength sweeping is realized by a chirped fiber Bragg grating (CFBG), which shows a superior temporal stability and power efficiency, compared with commonly used dispersive fibers, particularly in the 2.0 μm wavelength window. To showcase its specialties, here we employ it to perform high-speed spectrally-encoded microscopy (i.e., time-stretch imaging) through a scattering medium at a line-scan rate of up to ∼19 MHz. Better image quality is achieved, compared with a conventional imaging window at 1.0 μm. It is believed that the potential applications of this new high-speed swept source will benefit the transient diagnosis that requires deep penetration through a scattering medium.
我们报道了一种通过先进的时间拉伸技术工作在2.0μm波长的高速波长扫描光源。它以3.3×10 nm/s的速度和19 MHz的重复频率扫描超过30 nm的波长范围。据我们所知，这是首次在如此长的波长下实现兆赫兹稳定的扫描光源。一个简单的锁模光纤激光器实现了60 nm的波长覆盖范围，从而获得了宽带宽。全光波长扫描由啁啾光纤布拉格光栅（CFBG）实现，与常用色散光纤相比，它具有优异的时间稳定性和功率效率，特别是在2.0μm波长窗口。为了展示其特性，我们在此利用它通过散射介质以高达~19 MHz的线扫描速率进行高速光谱编码显微镜成像（即时间拉伸成像）。与1.0μm的传统成像窗口相比，获得了更好的图像质量。相信这种新型高速扫描光源的潜在应用将有利于需要穿透散射介质进行深度探测的瞬态诊断。
