Jung Minwan, Lee Junsu, Koo Joonhoi, Park Jaehyun, Song Yong-Won, Lee Kwanil, Lee Sangbae, Lee Ju Han
Opt Express. 2014 Apr 7;22(7):7865-74. doi: 10.1364/OE.22.007865.
We experimentally demonstrate a femtosecond mode-locked, all-fiberized laser that operates in the 2 μm region and that incorporates a saturable absorber based on a bulk-structured bismuth telluride (Bi(2)Te(3)) topological insulator (TI). Our fiberized saturable absorber was prepared by depositing a mechanically exfoliated, ~30 μm-thick Bi(2)Te(3) TI layer on a side-polished optical fiber platform. The bulk crystalline structure of the prepared Bi(2)Te(3) layer was confirmed by Raman and X-ray photoelectron spectroscopy measurements. The modulation depth of the prepared saturable absorber was measured to be ~20.6%. Using the saturable absorber, it is shown that stable, ultrafast pulses with a temporal width of ~795 fs could readily be generated at a wavelength of 1935 nm from a thulium/holmium co-doped fiber ring cavity. This experimental demonstration confirms that bulk structured, TI-based saturable absorbers can readily be used as an ultra-fast mode-locker for 2 μm lasers.
我们通过实验展示了一种飞秒锁模全光纤激光器，其工作在2μm波段，并集成了基于体结构碲化铋（Bi(2)Te(3)）拓扑绝缘体（TI）的可饱和吸收体。我们的光纤可饱和吸收体是通过将机械剥离的约30μm厚的Bi(2)Te(3) TI层沉积在侧面抛光的光纤平台上制备而成。通过拉曼光谱和X射线光电子能谱测量确认了所制备Bi(2)Te(3)层的体晶体结构。所制备的可饱和吸收体的调制深度测量为约20.6%。使用该可饱和吸收体，结果表明，在掺铥/钬的光纤环形腔中，在1935nm波长处能够轻松产生脉宽约为795fs的稳定超快脉冲。该实验证明证实，基于体结构的TI基可饱和吸收体可轻松用作2μm激光器的超快锁模器。
