Indium selenide film: a promising saturable absorber in 3‐ to 4‐μm band for mid‐infrared pulsed laser
Ting Hai, Guoqiang Xie, Zhen Qiao, Zhipeng Qin, Jie Ma, Yue Sun, Fengqiu Wang, Peng Yuan, Jingui Ma, Liejia Qian
Abstract
Abstract Indium selenide (InSe) film, an emerging two‐dimensional chalcogenide semiconductor, has recently attracted growing interests in optoelectronics. However, its nonlinear characteristics and application potentials in mid‐infrared (IR) region remain open, which is a very attractive but undeveloped spectral region currently. In this work, it is demonstrated that InSe film possesses excellent nonlinear absorption properties in 3‐ to 4‐μm band. Saturable absorption measurements of InSe film at 2.8 and 3.5 μm show very low saturation energy fluences and moderate modulation depths. Pump–probe measurements at 3 and 4 μm indicate that InSe film has ultrafast responses in mid‐IR region. Furthermore, the application of InSe film in mid‐IR pulsed laser is demonstrated, and stable Q‐switching operation of fiber laser at 2.8 μm is realized. These results show that InSe film is a promising saturable absorber for mid‐IR pulsed laser.