Single-crystal InSe fiber-based microlaser fabricated by a convenient molten core drawing technique

The layered van der Waals materials γ-InSe showed great potential in integrated photonic devices and microlasers due to the high electron mobility, wide tunable direct bandgap, and high lattice compressibility. However, γ-InSe crystal has weak stability and dissociation tendency in ambient conditions, which hampers its applications. Herein, we proposed a novel method for single-crystal InSe. By thermal stretching combined with photothermal processing, ultralong and layered single-crystal InSe fibers were obtained. The InSe fiber core was effectively restrained and protected, improving the mechanical properties and stability of the device. Moreover, by using a 532 nm nanosecond pulse laser as the pump source, the WGM microlaser operating at 1107.33 nm was obtained. This work provides a convenient approach for van der Waals materials preparation and paves the pathways for the development of light sources for layered van der Waals materials.