Efficient and broadband quarter-wave plates by gap-plasmon resonators

Area of Science:

• Photonics and Plasmonics
• Nanotechnology
• Optical Metamaterials

Background:

• Metal-insulator-metal (MIM) structures are key in plasmonics.
• Quarter-wave plates are essential optical components for polarization control.
• Achieving broadband and efficient quarter-wave plates remains a challenge.

Purpose of the Study:

• To numerically demonstrate efficient and broadband quarter-wave plates in reflection.
• To investigate metal-insulator-metal (MIM) configurations with nanobricks for plasmonic resonances.
• To explore the design of these structures for polarization control applications.

Main Methods:

• Numerical simulations of metal-insulator-metal (MIM) configurations.
• Design of nanobricks in the top metal layer to facilitate gap-surface plasmon resonances.
• Analysis of optical properties through analytical and numerical studies.

Main Results:

• Demonstrated quarter-wave plate behavior in reflection at λ ≈ 800 nm.
• Achieved a broad operation bandwidth of 160 nm.
• Reported a high conversion efficiency of 82% with a fixed angle of linear polarization across the bandwidth.

Conclusions:

• Periodic nanobricks in MIM configurations can function as efficient, broadband quarter-wave plates.
• Proper geometrical parameter selection is crucial for optimizing performance.
• The study provides insights into the underlying physics of structured MIM configurations for plasmonic applications.