非線性光學顯微鏡-使用鎖模光纖雷射產生之1.2-1.35微米切倫可夫輻射光源

Abstract

在過去的文獻中，1200-1350 nm波段已被證實是重要的生物穿透窗口。將此生物穿透窗口波段之光源應用於非線性光學顯微術上，可得到更深的穿透深度、優異的三維空間解析度與減少對生物體的光破壞之優點。因此我們在實驗上，以便利性、可攜帶性、操作容易與低成本的考量下，架設了一套1.2-1.35 μm飛秒級的切倫可夫光源，此實驗以一套1.55 μm被動鎖模摻鉺光纖雷射作為激發源，激發光源搭配非線性光纖作為波長轉換器產生幾十個毫瓦等級的1.2-1.35 μm脈衝(<100fs)雷射。並首次展示應用此全光纖化光源於非線性光學顯微鏡中來展現此套雷射便攜性與實用性，相較於其他傳統固態雷射，此套雷射擁有體積小、易操作、穩定性佳…等優點，在未來將雷射功率提升至百毫瓦級後必定能取代固態雷射，且應用範圍也會變廣。

An intimate all fiber femtosecond Cherenkov radiation laser source, operated in the 1200-1350 nm bio-penetration windows, was demonstrated for the first time. Utilizing a self-started passively-mode-locked Erbium-doped fiber laser as the excitation source and a nonlinear fiber as the wavelength converter, a portable fiber-based femtosecond Cherenkov source, operated at 1200-1350 nm bio-penetration wavelength window, was demonstrated with multi-tens milliwatt-level output power and 89 fs pulsewidth. Based on the demonstrated portable fiber-based femtosecond source, nonlinear microscopy, including two-photon fluorescence and second-harmonic generation microscopy was performed. The fiber-based light source shows great promises to serve as excitation sources for nonlinear light microscopy due to advantages of simplicity, easily-operated and low-cost.