Room-temperature DBR-free VCSEL operation on an InGaN/GaN thin-film platform with a monolithic surface grating

Area of Science:

• Optoelectronics
• Semiconductor Devices

Background:

• Vertical-Cavity Surface-Emitting Lasers (VCSELs) are crucial for data communication and sensing.
• Traditional VCSELs often rely on complex Distributed Bragg Reflectors (DBRs).

Purpose of the Study:

• To introduce a cost-effective VCSEL design using a monolithic top surface high contrast grating (HCG) reflector.
• To eliminate the need for DBRs, simplifying fabrication and potentially reducing costs.

Main Methods:

• Fabrication of a VCSEL with a monolithic surface HCG reflector on a thin-film substrate.
• Characterization using micro-photoluminescence measurements under optical pumping.

Main Results:

• Achieved room-temperature lasing at 436.2 nm.
• Demonstrated a Q factor of 4600 and a lasing threshold of 5.5 kW/cm².
• The HCG reflector significantly improved surface reflectivity, enabling vertical lasing.

Conclusions:

• The DBR-free VCSEL design with a surface HCG reflector is a viable and promising approach.
• This innovation offers a pathway to more cost-effective VCSELs.
• Potential applications include photonic integrated circuits and LiDAR systems.