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Wave-vector space picture for radiationless focusing and beaming
Varat Intaraprasonk1, Shanhui Fan
1Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Optics Letters
|October 2, 2009
Summary
Near-field focusing and beaming of electromagnetic waves at deep subwavelength scales are achieved by controlling wave propagation in the near field. This study presents a wave-vector space picture for designing such near-field phenomena.
Area of Science:
- Physics
- Electromagnetism
- Optics
Background:
- Radiationless interference in electromagnetic waves occurs at deep subwavelength scales in the near field.
- Understanding near-field wave propagation is crucial for subwavelength optics and nanophotonics.
Purpose of the Study:
- To present a wave-vector space picture for analyzing electromagnetic wave propagation in the deep subwavelength near-field regime.
- To determine the conditions for achieving near-field focusing.
- To design initial field distributions for near-field beaming.
Main Methods:
- Utilizing a wave-vector space picture to model wave propagation.
- Analyzing the conditions required for near-field focusing.
- Designing specific initial field distributions for beam shaping.
Main Results:
- The wave-vector space picture successfully reproduces the conditions for near-field focusing.
- A method for designing initial field distributions that maintain intensity shape during propagation (near-field beaming) was developed.
- A potential implementation for near-field beaming is proposed.
Conclusions:
- The wave-vector space picture provides a valuable tool for understanding and controlling near-field electromagnetic phenomena.
- Near-field beaming at deep subwavelength scales is achievable with designed initial field distributions.
- The proposed scheme offers a pathway for practical applications in nanophotonics.
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