Evanescent Wave Conversion Using Indefinite Electromagnetic Medium
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Solution Overview
Problem
Conventional far-field optical systems are limited by the diffraction limit, which restricts the resolution of images formed by evanescent electromagnetic waves that decay exponentially with distance, preventing their conversion to propagating waves beyond a certain range.
Innovation Solution
The use of an indefinite electromagnetic medium with hyperbolic dispersion relations allows for the conversion of evanescent electromagnetic waves to non-evanescent waves and vice versa, enabling the propagation of waves with large transverse wavevectors through structures with indefinite permittivity and permeability tensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional far-field optical systems are used, then the system is simple and well-understood, but the resolution is limited by the diffraction limit
Solution Approach 1:
The patent changes the electromagnetic parameters (permittivity and permeability) of the medium by introducing an indefinite medium with specific tensor values. This parameter change enables the conversion of evanescent waves to propagating waves, thereby improving resolution beyond the diffraction limit without fundamentally changing the optical system architecture.
Solution Approach 2:
The patent employs composite material structures with specific permittivity and permeability tensors to create the indefinite medium. These composite materials are designed to have anomalous electromagnetic properties that enable wave conversion while maintaining practical implementability.
2Measurement precision
If evanescent waves are used to enhance resolution, then the spatial resolution improves, but the waves decay exponentially and cannot propagate beyond the near-field region
Solution Approach 1:
The indefinite medium acts as an intermediary between the near-field evanescent waves and the far-field propagating waves. It converts the evanescent waves to propagating waves, enabling the information carried by evanescent waves to be transmitted beyond the near-field region while maintaining the enhanced resolution.
Solution Approach 2:
The patent induces a phase transition in the electromagnetic waves by converting them from evanescent (decaying) to propagating (oscillating) states. This phase transition occurs within the indefinite medium and enables the waves to propagate indefinitely while preserving the spatial frequency information for enhanced imaging.
3Measurement precision
If the indefinite medium is used to convert evanescent waves to propagating waves, then the resolution exceeds the diffraction limit, but the medium requires precise control of permittivity and permeability tensors
Solution Approach 1:
The patent segments the indefinite medium into discrete components or layers with specific permittivity and permeability tensors. This segmentation allows for more practical manufacturing by breaking down the complex material requirements into manageable sections that can be fabricated using existing techniques.
Solution Approach 2:
The patent provides specific parameter ranges and tensor values for the permittivity and permeability that can be achieved with current materials and manufacturing capabilities. By grounding the theoretical requirements in practical material properties, the patent makes the indefinite medium manufacturable while maintaining the wave conversion functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach exceeds the diffraction limit, enabling the conversion of evanescent waves to propagating waves, thereby enhancing the resolution and propagation capabilities beyond conventional optical systems.
Implementation Method 1
an evanescent electromagnetic wave conversion structure with indefinite electromagnetic parameters is responsive to an evanescent electromagnetic wave at a first surface region to convey a propagating electromagnetic wave from the first surface region to a second surface region and to provide a non-evanescent electromagnetic wave at the second surface region
Implementation Method 2
The development of an indefinite electromagnetic medium with varying permittivity and permeability tensors allows for the conversion of evanescent waves to non-evanescent waves and vice versa, enabling the propagation of electromagnetic waves with larger transverse wavevectors through the use of layered structures and transformation optics
Data Source
AI summary
Apparatus, methods, and systems provide conversion of evanescent electromagnetic waves to non-evanescent electromagnetic waves and/or conversion of non-evanescent electromagnetic waves to evanescent electromagnetic waves. In some approaches the conversion includes propagation of electromagnetic waves within an indefinite electromagnetic medium, and the indefinite medium may include an artificially-structured material such as a layered structure or other metamaterial.