Mid-Infrared Black Phosphorus Surface-Emitting Laser with an Open Microcavity

The compact and low-cost surface-emitting lasers in the 3-5 mu m 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 noise 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 microcavity on silicon. Optically pumped lasing at similar to 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 an open cavity. This is the first demonstration of a BP-based light-emitting device and thus paves a pathway toward monolithic integration of Si-photonics in the MIR range.