Mode Switching and Filtering in Nanowire Lasers.

Area of Science:

• Optics and Photonics
• Materials Science
• Nanoscience

Background:

• Coherent light sources below the vacuum wavelength limit are crucial for advanced nanophotonics.
• Semiconductor nanowire lasers offer a platform for subwavelength light emission.

Purpose of the Study:

• To investigate the angular emission of single semiconductor nanowire lasers.
• To understand mode dynamics and their impact on laser performance.
• To demonstrate mode filtering for enhanced light source characteristics.

Main Methods:

• Direct imaging of angular emission from ZnO nanowire lasers.
• Analysis of mode switching from fundamental to multimode operation.
• Fabrication and characterization of tapered nanowires for mode filtering.

Main Results:

• Lasing mode transitions from fundamental to higher-order modes in thicker nanowires.
• Mode competition significantly slows down laser dynamics.
• Tapered nanowires effectively select the fundamental mode, enhancing power, efficiency, and directionality.

Conclusions:

• Mode control in semiconductor nanowire lasers is essential for optimizing performance.
• Tapered nanowire structures provide efficient photonic mode filtering.
• These improved light sources are vital for integrated nanophotonic circuits and applications.