Bandgap engineering and prospects for radiation-balanced vertical-external-cavity surface-emitting semiconductor...

Area of Science:

• Semiconductor lasers
• Optics
• Materials science

Background:

• Vertical-external-cavity surface-emitting lasers (VECSELs) offer high power and beam quality.
• Thermal management is crucial to prevent VECSELs from operating outside single-mode regimes.
• Optical cooling provides a non-contact method for VECSEL thermal management.

Purpose of the Study:

• Investigate active medium characteristics for radiation balance lasing (RBL) in VECSELs.
• Determine operating conditions conducive to RBL.
• Provide a method for optimizing semiconductor gain media for RBL.

Main Methods:

• Theoretical investigation of semiconductor gain media.
• Analysis of density of states engineering.
• Modeling of anti-Stokes luminescence and optical gain.

Main Results:

• Achieving RBL requires a specific density of states in the gain medium.
• Engineered density of states must support both optical gain and strong anti-Stokes luminescence.
• Bandtail states, impurities, or quantum dots can facilitate RBL.

Conclusions:

• Band structure engineering is essential for VECSEL optical cooling.
• Optimized VECSEL gain media can achieve lower thresholds and higher output powers.
• RBL is attainable in semiconductor VECSELs through careful material design.