Spatial Light Modulator Pseudo Speckle Pattern Generation
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Solution Overview
Problem
Existing methods for generating speckle patterns lack flexibility in setting spatial structure and light intensity statistical distribution, requiring multiple diffusers or limited adjustments, and struggle with reproducibility.
Innovation Solution
A pseudo speckle pattern generation apparatus using a spatial light modulator with settable intensity or phase modulation distributions, controlled by a pseudo random number pattern and correlation function, to produce customizable speckle patterns with high reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diffuser is used to generate speckle patterns, then the device complexity is reduced, but the degree of freedom in setting spatial structure and light intensity statistical distribution is limited
Solution Approach 1:
The patent replaces the mechanical system of using multiple physical diffusers with an optical system using a spatial light modulator that can be programmatically controlled. The SLM allows dynamic adjustment of modulation distributions (amplitude, phase, or both) to generate different speckle patterns without changing physical components, thereby reducing device complexity while maintaining high adaptability.
Solution Approach 2:
The patent introduces dynamic control of the speckle generation process through a spatial light modulator that can change its modulation distribution in real-time based on control signals. This allows the system to adaptively generate various speckle patterns with different spatial structures and statistical distributions by simply updating the modulation pattern, providing high degree of freedom without adding physical components.
2Adaptability or versatility
If multiple diffusers are prepared to generate various speckle patterns, then the adaptability in setting spatial structure and light intensity statistical distribution is improved, but the device complexity and preparation requirements increase
Solution Approach 1:
The patent makes a single spatial light modulator perform multiple functions that would otherwise require multiple different diffusers. By programmatically controlling the modulation distribution (amplitude, phase, or both) of the SLM, one device can generate various speckle patterns with different spatial structures and statistical distributions, eliminating the need to prepare and manage multiple physical diffusers.
Solution Approach 2:
The patent changes the operational parameters of the spatial light modulator (modulation distribution, modulation depth, phase patterns) to generate different speckle patterns. Instead of changing physical components, the system achieves adaptability by dynamically adjusting controllable parameters of the SLM, allowing flexible setting of spatial structure and light intensity statistical distribution without increasing device complexity.
3Adaptability or versatility
If speckle patterns are generated by changing diffuser position, then various patterns can be obtained, but the reproducibility of the same pattern becomes extremely difficult
Solution Approach 1:
The patent implements a control system that can store and reproduce specific modulation distributions for the spatial light modulator. This allows the system to reliably reproduce the same speckle pattern by reapplying the stored control signal, eliminating the reproducibility issues associated with physically moving diffusers. The control unit ensures consistent pattern generation through digital control and storage of modulation parameters.
4Adaptability or versatility
If a spatial light modulator with two-dimensional pseudo random number pattern is used, then speckle patterns can be generated, but only the contrast can be adjusted, providing low degree of freedom
Solution Approach 1:
The patent extends the modulation capabilities of the spatial light modulator beyond simple contrast adjustment to include independent control of amplitude modulation distribution and phase modulation distribution. By changing these parameters, the system can control both the spatial structure (through phase) and the light intensity statistical distribution (through amplitude), significantly increasing the degree of freedom in setting speckle pattern properties while using a single programmable device.
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 provides a high degree of freedom in setting spatial structure and light intensity statistical distribution, enabling high reproducibility and flexibility in generating pseudo speckle patterns suitable for various applications, including optical manipulation and measurement techniques.
Implementation Method 1
When coherent light such as laser light is scattered by a diffuser (scattering medium) such as a diffuser plate, a speckle pattern is generated by interference of the scattered light
Implementation Method 2
a speckle pattern is generated by interference of the scattered light
Data Source
AI summary
A pseudo speckle pattern generation apparatus includes a light source, a beam expander, and a spatial light modulator. The spatial light modulator has an intensity modulation distribution based on a pseudo speckle pattern calculated from a pseudo random number pattern and a correlation function, receives light output from the light source and increased in beam diameter by the beam expander, spatially modulates the received light according to the modulation distribution, and outputs modulated light.