Mid-infrared Black Phosphorus Surface-emitting Laser with an Open Micro-cavity

The compact and low cost surface-emitting lasers in 3-5 μm mid-infrared (MIR) range are highly desirable for important applications such as gas detection, noninvasive medical diagnosis and infrared scene projection. Due to the intrinsic noisy of general narrow-bandgap semiconductors, the MIR is a challenging region for photonics. Here, we demonstrate the first black phosphorus (BP) based MIR surface-emitting laser operating at room temperature fabricated with BP as the active gain materials embedded into a SiO2/Si3N4 open micro-cavity on silicon. Optically pumped lasing at ~3765 nm is successfully realized in the demonstrated device by significantly increased luminescence efficiency in the BP lamellar structure and resolving the general issues for processing BP and other two-dimensional materials as gain medium with the specific design of open cavity. This is the first demonstration of BP based light emitting device, and thus paves a pathway towards monolithic integration of Si-photonics in the MIR range.