Wide-Wavelength Tunable Mid-Infrared Lasing Based on Black Arsenic Phosphorus

Mid-infrared (MIR) semiconductor laser sources are essential for applications in gas detection, infrared imaging, and high-speed free space optical communications. At present, the dynamic wavelength tunability of MIR lasers based on lead salt, antimonide, and quantum cascade lasers is limited and their compact size as well as heterogeneous integration are still challenging. Two-dimensional (2D) materials, used as optical gain materials, have the flexible tunability and compatible van der Waals integrations—providing many new possibilities for constructing MIR laser sources of large tunability and high integration. Here, wide-wavelength tunable MIR vertical cavity surface emitting lasers (VCSELs) integrated on silicon substrates are realized based on 2D black arsenic phosphorus (b-As_xP_1−x). The emission wavelength of the optically pumped laser device is demonstrated to be tuned from 3.42 to 4.65 µm at room temperature, which could be controlled by adjusting the alloy composition and thickness of the gain media b-As_xP_1−x. The tunable MIR VCSEL device would pave the way for further exploration of 2D materials-based IR lasers working as on-chip light sources.