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Updated: Aug 6, 2026
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Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons
Published on: July 21, 2018
Approaching the low optical loss limit of plasmonics using potassium
Yi Zhang1,2, Yuhan Yang1, Jie Liang1
1National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Key Laboratory of Intelligent Optical Sensing and Manipulation, Nanjing University, Nanjing, 210093, China.
Light, Science & Applications
|July 21, 2026
Summary
Potassium offers a low-loss plasmonic material alternative to noble metals. This research fabricates high-quality potassium films, achieving significantly reduced optical damping for advanced photonic devices.
Area of Science:
- Materials Science
- Optics
- Nanotechnology
Background:
- Plasmonics allows photonic device miniaturization below the optical diffraction limit.
- Noble metals, commonly used in plasmonics, suffer from high ohmic losses, limiting device performance.
Purpose of the Study:
- To investigate potassium as a low-loss plasmonic material.
- To overcome the inherent loss-confinement tradeoff in current plasmonic systems.
Main Methods:
- Fabrication of ultra-flat, high-quality potassium films using a slipping-assisted oxide-free crystallization process.
- Optical damping rate measurements.
- Near-field optical spectroscopic measurements.
Main Results:
- Potassium films exhibit an optical damping rate as low as 2.27 meV.
- Measured imaginary permittivity is approximately 0.1 across the visible to near-infrared range (400-2000 nm).
- Spectroscopic measurements confirmed deep subwavelength confinement of optical modes, indicating reduced losses.
Conclusions:
- Potassium is a promising low-loss plasmonic material.
- This work establishes a new platform for exploring extreme light-matter interactions.
- Potassium-based plasmonics can advance photonic device capabilities.
