Indium selenide for mode-locked pulse generation in a Mid-infrared Er:ZBLAN fiber laser

Two-dimensional materials are increasingly recognized for their distinctive nonlinear optical properties. Indium selenide (InSe), a notable optoelectronic material, demonstrates unique advantages in terms of nonlinear absorption behavior, making it a promising candidate in mid-infrared mode-locked lasers. By preparing a InSe saturable absorber (SA) and applying it in a Er: ZBLAN fiber laser, we demonstrate a stable mode-locked mid-infrared fiber laser at 2.8 μm. The obtained mode-locked pulses have a repetition frequency and pulse duration of 29.875 MHz and 13.6 ps, respectively. The obtained maximum value of pulse energy is 4.3 nJ. The signal-to-noise ratio (SNR) is 55 dB, indicating the high stability of the laser system. Our experimental results validate that InSe is a promising SA in the near 3 μm band. This work paves the way for further investigations and applications of InSe-based devices in nonlinear optics and mode-locked laser systems.