SBIR-STTR Award

We propose achieving high power mid-infrared arrays with interband cascade vertical cavity surface emitting lasers (VCSEL). Unlike quantum cascade lasers, optical selection rules in interband cascade lasers allow vertical emission. The massive parallelism of a VCSEL array will allow small, low power lasers to achieve high total output power with no speckle due to spatial incoherence across the array. Mid-infrared VCSELs have already achieved room temperature, continuous wave operation. We propose improving on state-of-the-art using several innovative approaches: growth on Si for improved thermal management; lower absorption cavity design; improved quantum well design; an oxide aperture to reduce loss by moving the optical mode and the pumped active region away from sidewalls, and improving their overlap; and electroplating with the very high thermal conductivity copper. To extract the heat, we propose modelling of heat pipes to spread the heat over a larger area, then a cold plate to extract heat from the heat pipe. To combine beams from different VCSELs, we propose using COMSOL ray matrix to model microlens arrays combined with macroscopic lenses.

Benefit:
The high-power MIR VCSEL arrays fit well into our companys focus on MIR light sources and integration of them into commercial technologies. We have expertise and interest in manufacturing MIR lasers for component sales, and integration into gas sensors and medical technologies. We plan to begin by selling optoelectronics components (MIR semiconductor LEDs and lasers), then eventually integrate them into gas sensors for sensing gases such as carbon dioxide, sulphur dioxide, and nitrogen oxide. We have already been contacted by major gas sensor companies such as MKS Instruments, and MTEQ. In the next five years, we expect to launch several products, such as component high power MIR LEDs, participation in IRLED thermal scene projector manufacturing stage under CTEIP funding to the Department of Defense, IR gas sensors, and component high power MIR lasers and laser arrays in the 3-6 m wavelength range.

Keywords:
analytical modeling for heat extraction, analytical modeling for heat extraction, beam combining for high power emission, Interband lasers, VCSEL arrays