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Gao Z, Wildenborg A, Kocoj CA, Liu E, Sheofsky C, Rawashdeh A, Qu H, Guo P, Suh JY, Yang A. Low-Loss Plasmonics with Nanostructured Potassium and Sodium-Potassium Liquid Alloys. Nano Lett 2023; 23:7150-7156. [PMID: 37477493 DOI: 10.1021/acs.nanolett.3c02054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Alkali metals have low optical losses in the visible to near-infrared (NIR) compared with noble metals. However, their high reactivity prohibits the exploration of their optical properties. Recently sodium (Na) has been experimentally demonstrated as a low-loss plasmonic material. Here we report on a thermo-assisted nanoscale embossing (TANE) technique for fabricating plasmonic nanostructures from pure potassium (K) and NaK liquid alloys. We show high-quality-factor resonances from K as narrow as 15 nm in the NIR, which we attribute to the high material quality and low optical loss. We further demonstrate liquid Na-K plasmonics by exploiting the Na-K eutectic phase diagram. Our study expands the material library for alkali metal plasmonics and liquid plasmonics, potentially enabling a range of new material platforms for active metamaterials and photonic devices.
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Affiliation(s)
- Zhi Gao
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Aaron Wildenborg
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Conrad A Kocoj
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Eric Liu
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Caden Sheofsky
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Abdelsalam Rawashdeh
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Hongwei Qu
- Department of Electrical & Computer Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Peijun Guo
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Jae Yong Suh
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Ankun Yang
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
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Rawashdeh A, Wildenborg A, Liu E, Gao Z, Czaplewski DA, Qu H, Suh JY, Yang A. High-Quality Surface Plasmon Polaritons in Large-Area Sodium Nanostructures. Nano Lett 2023; 23:469-475. [PMID: 36630601 DOI: 10.1021/acs.nanolett.2c03643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Sodium (Na) is predicted to be an ideal plasmonic material with ultralow optical loss across visible to near-infrared (NIR). However, there has been limited research on Na plasmonics. Here we develop a scalable fabrication method for Na nanostructures by combining phase-shift photolithography and a thermo-assisted spin-coating process. Using this method, we fabricated Na nanopit arrays with varying periodicities (300-600 nm) and with tunable surface plasmon polariton (SPP) modes spanning visible to NIR. We achieved SPP resonances as narrow as 9.3 nm. In addition, Na nanostructures showed line width narrowing from visible toward NIR, showing their prospect operating in the NIR. To address the challenges associated with the high reactivity of Na, we designed a simple encapsulation strategy and stabilized the Na nanostructures in ambient conditions for more than two months. As a low-cost and low-loss plasmonic material, Na offers a competitive option for nanophotonic devices and plasmon-enhanced applications.
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Affiliation(s)
- Abdelsalam Rawashdeh
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan48309, United States
| | - Aaron Wildenborg
- Department of Physics, Michigan Technological University, Houghton, Michigan49931, United States
| | - Eric Liu
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan48309, United States
| | - Zhi Gao
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan48309, United States
| | - David A Czaplewski
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois60439, United States
| | - Hongwei Qu
- Department of Electrical & Computer Engineering, Oakland University, Rochester, Michigan48309, United States
| | - Jae Yong Suh
- Department of Physics, Michigan Technological University, Houghton, Michigan49931, United States
| | - Ankun Yang
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan48309, United States
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