Spatially modulated broad-area lasers for narrow lateral far-field divergence

Area of Science:

• Optics and Photonics
• Semiconductor Lasers

Background:

• High-power semiconductor lasers often suffer from poor beam quality.
• Achieving a narrow far-field profile is crucial for applications like directed energy and optical communications.

Purpose of the Study:

• To present a novel laser design incorporating longitudinal-lateral gain-loss modulation and phase tailoring.
• To investigate the far-field characteristics of this new laser structure.

Main Methods:

• Utilizing a novel laser design with etched rectangular trenches for phase tailoring.
• Performing simulations to predict far-field profiles.
• Conducting experimental measurements of far-field intensity for pulsed operation.

Main Results:

• Simulations predict a narrow far-field profile with a 0.3° full width at half maximum.
• A 0.4°-wide main lobe is predicted to contain 40% of the emitted optical power.
• Experimental results confirm enhanced radiation in the central angular range, but high intensity outside the main peak.

Conclusions:

• The novel laser design shows promise for improving beam quality in high-power semiconductor lasers.
• Further optimization is needed to reduce far-field intensity outside the central lobe.
• This design offers a potential pathway towards more efficient and focused laser systems.