Configurable Grating via Collapsing Nano-Fingers
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Solution Overview
Problem
Current sub-wavelength gratings lack the ability to be reconfigured for broader applications, such as in liquid crystal displays, where rapid configuration changes are limited by polymer re-alignment times, and they cannot be made sub-wavelength in the optical domain for liquid crystal cells.
Innovation Solution
A configurable sub-wavelength grating based on collapsing nano-finger technology, where the nano-fingers can be controlled to change their configuration through mechanisms like electrostatic, magnetic, or mechanical means, altering transmission/reflection properties and allowing for reversible states, enabling faster and more flexible optical element designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional liquid crystal cells are used for optical control, then voltage control is convenient, but the response time is limited by polymer re-alignment and cannot achieve sub-wavelength dimensions
Solution Approach 1:
The liquid crystal cell is segmented into multiple independently addressable sub-regions or pixels, each capable of rapid switching. This segmentation allows parallel operation and reduces the effective response time for each individual element while maintaining overall display capability
Solution Approach 2:
The patent replaces traditional mechanical polymer re-alignment mechanisms with an electro-optical switching mechanism using liquid crystals. This substitution eliminates the slow mechanical re-alignment process and enables rapid voltage-controlled switching at sub-wavelength dimensions
2Adaptability or versatility
If sub-wavelength gratings are used for optical filtering, then broadband resonance and angular tolerance are achieved, but reconfigurability is lost
Solution Approach 1:
The grating structure incorporates dynamically controllable elements such as liquid crystal-filled regions or movable components that can change their optical properties in real-time. This allows the grating to switch between different diffraction orders, wavelengths, or modulation states while maintaining sub-wavelength dimensions and optical performance
3Use of energy by moving object
If high-index-contrast gratings are used to trap guided waves, then resonance is enhanced, but lateral propagation distance is reduced
Solution Approach 1:
The grating structure employs spatially varying index contrast or geometric parameters along the propagation direction. This allows different regions of the grating to serve different functions: some regions provide strong resonance enhancement while other regions facilitate gradual mode conversion and extended lateral propagation
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
The grating achieves sub-wavelength dimensions with high index materials, providing enhanced flexibility in design and enabling faster display configurations without the limitations of traditional liquid crystal technologies, while allowing for precise determination of nano-finger states through spectral analysis.
Implementation Method 1
the nano-fingers can be controlled to change their configuration through mechanisms like electrostatic, magnetic, or mechanical means
Implementation Method 2
the nano-fingers can be controlled to change their configuration through mechanisms like electrostatic, magnetic, or mechanical means
Implementation Method 3
Resonant effects in dielectric gratings were identified in the early 1990's as having promising applications to free-space optical filtering and sensing
Implementation Method 4
the first-order diffracted mode corresponds not to freely propagating light but to a guided wave trapped in some dielectric layer
Implementation Method 5
When a high-index-contrast grating is used, the guided waves are rapidly scattered and do not propagate very far laterally
Data Source
AI summary
A configurable grating based on collapsing nano-fingers includes a substrate; and a plurality of bendable nano-fingers supported on the substrate. The nano-fingers may be formed in a regular first array and the nano-fingers may be formed in a spacing that, upon closing at their tops, forms a second array to act as an optical grating or a diagnostic tool. A method of fabricating a configurable optical grating based on collapsing nano-fingers is also disclosed, as well as a method of determining an open or closed state for a plurality of nano-fingers.