Photonic Diode 3D Nano-Structure Asymmetric Transmission
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Solution Overview
Problem
Existing photonic diodes struggle to achieve asymmetric light transmission for linear polarization, as they require a three-dimensional structure which is difficult to manufacture using conventional methods, whereas circular polarization can be achieved with two-dimensional structures.
Innovation Solution
A method for manufacturing a photonic diode using three-dimensional electron beam patterning, specifically creating a meta-material structure with a three-dimensional nano-structure that allows asymmetric light transmission by breaking the symmetry about the z-axis, enabling light to pass only in one direction for linear polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-dimensional structure is used to achieve asymmetric light transmission for linear polarization, then the asymmetric transmission performance is improved, but the manufacturing difficulty increases
Solution Approach 1:
The patent transitions from conventional two-dimensional photonic crystal structures to three-dimensional inverted pyramid structures. This dimensional change enables asymmetric light transmission for linear polarization by creating non-reciprocal optical paths, where light traveling in opposite directions experiences different effective refractive indices and transmission characteristics due to the broken spatial symmetry of the 3D structure.
Solution Approach 2:
The patent implements asymmetric transmission by designing inverted pyramid structures with specific geometric parameters (side lengths, heights, spacing) that break the spatial symmetry about the z-axis. The asymmetric geometry creates different optical responses for forward and backward propagating light, enabling the photonic diode functionality where transmission coefficient differs significantly between opposite directions.
2Ease of manufacture
If conventional manufacturing methods are used, then the manufacturing process is simple, but the three-dimensional nano-structure cannot be fabricated
Solution Approach 1:
The patent replaces conventional mechanical lithography and etching methods with electron beam lithography and reactive ion etching. The electron beam lithography system uses focused electron beams to directly write three-dimensional patterning information onto the resist, enabling precise 3D nano-structure fabrication at the nanometer scale that cannot be achieved with optical lithography due to diffraction limits.
Solution Approach 2:
The patent utilizes controlled changes in process parameters during reactive ion etching (RF power, gas flow rates, pressure, etch time) to transform the two-dimensional electron beam pattern into a three-dimensional inverted pyramid structure. By adjusting etch selectivity and anisotropy through parameter optimization, the desired 3D geometry with precise dimensional control is achieved.
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 solution effectively achieves asymmetric light transmission for linear polarization by fabricating a three-dimensional nano-structure using electron beam lithography, demonstrating significant asymmetric transmission characteristics at specific frequencies, while maintaining symmetric transmission for circular polarization.
Implementation Method 1
the present disclosure relates to a technique for manufacturing a photonic diode capable of passing light only in one direction asymmetrically with respect to linear polarization using three-dimensional electron beam patterning
Data Source
AI summary
A photonic diode includes a first meta-material structure having a first bar and a second meta-material structure having a second bar arranged in a direction perpendicular to the first bar. The first bar and the second bar are separated from each other. Further, the first bar and the second bar are at least partially overlapped when viewed from a light propagation direction.