Orbital Angular Momentum Apparatus Using Optical Resonator
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Solution Overview
Problem
Existing technologies for generating orbital angular momentum (OAM) beams are limited by their inability to produce high-dimensional OAM states dynamically, are bulky, and have low integration potential, which hinders their application in quantum cryptography and quantum key distribution.
Innovation Solution
An orbital angular momentum generating apparatus using a holographic grating switch, spiral phase plates, and total reflectors to form a round-trip light path, enabling high-speed modulation of OAM states and superposition states with any topological charge number, featuring a compact structure and low manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spatial light modulator is used to dynamically modulate different OAM modes, then the adaptability is improved, but the response rate is below KHz and the device size is large
Solution Approach 1:
The patent replaces the mechanical spatial light modulator with an all-optical resonant cavity system. The optical resonator uses the Kerr effect (nonlinear optical effect) to achieve dynamic modulation of OAM modes without mechanical moving parts, thereby increasing the response rate from below KHz to potentially higher frequencies while maintaining adaptability.
Solution Approach 2:
The optical resonator system serves multiple functions: it generates OAM modes, modulates different topological charges, and achieves dynamic control all within a single integrated device. This multi-functionality eliminates the need for large, complex mechanical modulators while improving response speed.
2Manufacturing precision
If a spiral phase plate is used to generate OAM, then the manufacturing precision is improved, but the device complexity increases and only single-mode OAM can be realized
Solution Approach 1:
The patent combines multiple spiral phase plates with different topological charges into a single optical resonator system. By integrating multiple phase modulation functions into one device and utilizing optical resonance, the system can generate multiple OAM modes simultaneously or sequentially, reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent introduces dynamic control capabilities to the phase modulation system. By using the Kerr effect in the optical resonator, the system can dynamically switch between different OAM modes and superposition states, transforming a static single-mode generator into a dynamic multi-mode system without increasing structural complexity.
3Adaptability or versatility
If a q-plate is used to convert spin-orbit angular momentum, then the adaptability is improved, but the OAM dimension is limited and the mode is single
Solution Approach 1:
The patent embeds multiple q-plates with different properties within the optical resonator system. By nesting multiple spin-orbit conversion elements together and utilizing their combined effects through resonance, the system can generate higher-dimensional OAM states and multiple modes simultaneously, overcoming the single-mode limitation of individual q-plates while maintaining spin-orbit conversion capability.
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 apparatus can generate OAM states and superposition states at high speeds, up to the magnitude of MHz, with a compact structure and low manufacturing cost, overcoming the limitations of existing technologies by enabling dynamic modulation and integration.
Implementation Method 1
holographic grating switch
Implementation Method 2
spiral phase plate
Implementation Method 3
An optical beam with Orbital Angular Momentum (OAM) with phase factor exp (ilθ) carries lh orbital angular momentum
Implementation Method 4
total reflector
Implementation Method 5
OAM superposition states
Data Source
AI summary
The disclosure provides an orbital angular momentum generating apparatus for polarization modulation of orbital angular momentum and method thereof, comprising a Gaussian light source module, a first orbital angular momentum modulation module, a second orbital angular momentum modulation module and a multiplexing module; when working, the Gaussian light source module generates a Gaussian light beam in any polarization state and enters the multiplexing module, which decomposes the Gaussian light beam into two component light components, both of which are respectively directed into the first or the second orbital angular momentum modulation module, the modulation module respectively performs orbital angular momentum modulation on the two modulated light components, which return to the multiplexing module, the multiplexing module superposes the two component lights, and finally the orbital angular momentum state or the superposed state is output.