Waveguide Faceplate Using Transverse Anderson Localization
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Solution Overview
Problem
Conventional wave transmitters using total internal reflection (TIR) faceplates suffer from low transmission efficiency due to omnidirectional emission of light, capturing only a small percentage (3-6%) of emitted electromagnetic radiation, as most light is lost through the sides of the fibers.
Innovation Solution
The use of optically transmissive materials with a random transverse distribution of refractive indices, known as Transverse Anderson Localization (TAL), to guide light efficiently, incorporating conversion materials like scintillating or wavelength-shifting materials to generate and direct light along a consistent refractive index path, effectively increasing capture efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If total internal reflection (TIR) faceplates are used to transmit light, then light transmission can be achieved, but transmission efficiency is very low (only 3-6% of emitted light is captured)
Solution Approach 1:
The patent changes the fundamental parameter of light guidance from total internal reflection (TIR) to transverse Anderson localization (TAL). This involves transforming the refractive index distribution from a uniform or simple graded structure to a random transverse distribution with specific statistical properties. The random distribution creates multiple scattering paths that guide light along the fiber axis, capturing photons emitted at angles up to approximately 40 degrees from the axis, thereby increasing capture efficiency from 3-6% to potentially 50% or higher.
Solution Approach 2:
The patent employs composite material structures to achieve the random transverse refractive index distribution. This involves combining materials with different refractive indices in a random spatial arrangement, creating a composite structure that exhibits TAL properties. The composite nature allows for tailored optical properties while maintaining the random distribution necessary for efficient light guidance.
2Device complexity
If conventional TIR faceplates are used, then device structure is simple, but most electromagnetic radiation is lost through the sides of the fibers
Solution Approach 1:
The patent transforms the refractive index parameter from a uniform or simple graded distribution to a random transverse distribution. This parameter change fundamentally alters the light guidance mechanism, enabling the capture and guidance of photons that would otherwise be lost at angles up to 40 degrees from the fiber axis, thereby reducing electromagnetic radiation loss significantly.
Solution Approach 2:
The random transverse refractive index distribution acts as an intermediary mechanism between the emitted photons and the fiber axis. Instead of relying on direct axial emission or simple reflection, the random refractive index structure creates multiple scattering events that gradually redirect photons toward the axis, serving as a mediator that captures and guides light that would otherwise be lost.
3Measurement precision
If TIR mechanism is used for wave guiding, then alignment requirements are strict, but transmission efficiency is limited by numerical aperture
Solution Approach 1:
The patent changes the guiding parameter from dependence on precise alignment and numerical aperture (TIR mechanism) to dependence on random refractive index distribution (TAL mechanism). This parameter change allows the system to capture photons over a broader angular range without requiring strict alignment between the emitter and fiber input, as the random scattering paths inherently guide light along the axis regardless of initial emission angle.
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 significantly enhances light transmission efficiency to near 50% by guiding photons emitted at various angles, compared to the limited efficiency of TIR-based systems, making it suitable for applications like medical imaging and national security.
Implementation Method 1
arranging optically transmissive material to provide longitudinal waveguiding with a random transverse distribution of refractive indices effective to localize a transverse extent of conversion light propagating in the optical waveguide
Implementation Method 2
incorporating a conversion material (e.g., scintillating or wavelength-shifting material) into the optically transmissive material to generate the conversion light by interaction between the conversion material and incident radiation
Implementation Method 3
incorporating a conversion material (e.g., scintillating or wavelength-shifting material) into the optically transmissive material to generate the conversion light
Data Source
AI summary
A wave guide face plate for transmitting an image formed in a scintillating material included as part of a transmitting medium is disclosed. The transmitting medium includes a random distribution of different refractive index regions in two orthogonal dimensions, and an essentially consistent refractive index in a third orthogonal dimension. The third orthogonal direction is aligned with a transmission axis of the wave transmitter extending from an input location to a wave detector location. The transmission efficiency of the wave guide faceplate is improved in situations where the entry angle of the input radiation is different from the axis of the wave transmitter as compared to conventional faceplates.