Hybrid modes in plasmonic cavity array for enhanced hot-electron photodetection

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Hot-electron photodetectors offer high sensitivity and speed.
• Plasmonic structures can enhance light absorption in photodetectors.
• Silicon photonics is a key platform for optical communication.

Purpose of the Study:

• Investigate plasmonic characteristics of periodic cavities in silicon for hot-electron photodetection.
• Explore the potential of hybrid plasmonic modes for enhanced light absorption.
• Optimize photodetectors for single-band and dual-band detection at optical communication wavelengths.

Main Methods:

• Numerical simulation of plasmonic resonances in a silicon substrate with periodic cavities.
• Analysis of metal absorption maps to identify key plasmonic modes.
• Characterization of hybrid modes formed by cavity surface plasmons and Bragg-surface plasmon polaritons.

Main Results:

• Identified resonances of cavity surface plasmons (air and silicon) and Bragg-surface plasmon polaritons.
• Demonstrated that hybrid modes strongly enhance metal absorption.
• Showcased the potential for optimizing hot-electron photodetectors.

Conclusions:

• Periodic cavities in silicon exhibit rich plasmonic behavior relevant to photodetection.
• Hybrid plasmonic modes are crucial for enhancing light absorption in metal.
• The findings enable the design of optimized single- and dual-band hot-electron photodetectors for optical communication.