Improving optical coherence of light-emitting diodes by surface plasmons via shallow-etched conic pit array

Area of Science:

• Optoelectronics
• Plasmonics
• Semiconductor Devices

Background:

• Light-emitting diodes (LEDs) are crucial optoelectronic devices.
• Improving the coherence of emitted light from LEDs is an ongoing research area.
• Surface plasmon resonance offers potential for manipulating light-matter interactions.

Purpose of the Study:

• To investigate the coupling of multiple quantum wells and surface plasmons for enhanced light coherence in LED wafers.
• To demonstrate a novel architecture for generating partially coherent light from LEDs.

Main Methods:

• Fabrication of a shallow-etched conic pit array with evaporated silver (V-Ag) on a Gallium Nitride (GaN)-based LED wafer.
• Characterization of spatial coherence using angle-resolved spectra.
• Measurement of temporal coherence length.

Main Results:

• The V-Ag wafer exhibited significantly improved spatial coherence compared to a plain wafer.
• Temporal coherence length was found to be 1.4 times larger in the V-Ag wafer.
• The coherence-enhanced wafer demonstrated anisotropic and deflective emission characteristics.

Conclusions:

• Coupling quantum wells with surface plasmons effectively enhances light coherence in LED wafers.
• The V-Ag architecture provides a straightforward method for achieving partially coherent light emission.
• This research opens new avenues for plasmonic LED development and partially coherent light generation.