Suspended LRSPP for the development of highly integrated active plasmonic devices

Area of Science:

• Photonics and Plasmonics
• Optical Engineering
• Materials Science

Background:

• Surface plasmon polaritons (SPPs) are crucial for nanoscale light manipulation.
• Long-range SPPs (LRSPPs) offer reduced propagation losses but are sensitive to substrate interactions.
• Thermo-optic effects in plasmonic devices are vital for tunable applications.

Purpose of the Study:

• To introduce a novel suspended LRSPP device architecture.
• To investigate the suppression of substrate influence on LRSPP propagation.
• To enhance the thermo-optical response of LRSPP waveguides.

Main Methods:

• Fabrication of a suspended dielectric matrix with an embedded metallic waveguide.
• Integration of an air gap beneath the lower cladding to isolate the waveguide.
• Electrical current application to induce thermo-optical effects and measurement of optical losses and phase changes.

Main Results:

• Substrate influence is suppressed by the air gap, preserving thermo-optical distribution symmetry.
• Minimal optical losses were observed over extended electrical current ranges.
• The suspended device achieved a three-fold increase in phase change for a fixed power, or a ten-fold reduction in device length for a fixed phase change, compared to non-suspended structures.

Conclusions:

• The suspended LRSPP device offers superior thermo-optical modulation capabilities.
• This architecture provides a promising platform for efficient and compact plasmonic devices.
• The design overcomes limitations of substrate-dependent losses and performance degradation.