Phase Modulating Spatial Light Modulator for Beam Quality Control
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Solution Overview
Problem
Conventional spatial light modulators with a phase modulation range of 2π suffer from degradation in beam quality due to phase folding, leading to undesired intensity and phase distributions in the output light, making it difficult to achieve a desired beam section.
Innovation Solution
A light control device and method utilizing a phase modulating spatial light modulator capable of phase modulation in a range of 4π or more, which presents a phase pattern produced by superimposing a blazed grating pattern and a phase pattern with a predetermined phase modulation distribution, allowing for adjustable light diffraction efficiency to achieve a desired beam section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If phase folding is applied to compress phase modulation range to 2π, then device complexity is reduced, but beam quality deteriorates due to undesired intensity and phase distributions
Solution Approach 1:
The patent changes the phase modulation range parameter from the conventional 2π to a wider range of 4π or more. This parameter change eliminates the need for phase folding, thereby preventing the degradation of beam quality while maintaining manageable device complexity through the use of a blazed grating pattern for intensity control
Solution Approach 2:
The patent segments the phase modulation function into two independent components: a blazed grating pattern for intensity control and a phase modulation distribution for phase control. This segmentation allows each component to be optimized independently, achieving both intensity and phase control without the need for phase folding
2Manufacturing precision
If phase modulation range is increased to 4π or more, then beam quality is improved by avoiding phase folding, but device complexity increases
Solution Approach 1:
The patent divides the complex phase modulation task into two simpler sub-tasks: intensity modulation via blazed grating and phase modulation via phase distribution. This segmentation reduces the complexity of controlling each individual component while achieving the overall goal of high-quality beam output
Solution Approach 2:
The spatial light modulator is designed to perform multiple functions simultaneously: it applies the blazed grating pattern for intensity control and the phase modulation distribution for phase control within a single device operation. This multi-functionality eliminates the need for separate intensity and phase modulators, thereby managing device complexity
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 enables the attainment of light with a desired beam section, improving beam quality by avoiding phase folding and allowing for precise control of intensity and phase distributions, even in complex beam modes like Laguerre-Gaussian mode beams.
Implementation Method 1
a phase modulating spatial light modulator that is capable of phase modulation in each of a plurality of two-dimensionally arrayed pixels
Implementation Method 2
a blazed grating pattern for light diffraction
Data Source
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AI summary
A light control device 1 includes a light source 10, a prism 20, a spatial light modulator 30, a drive unit 31, a control unit 32, a lens 41, an aperture 42, and a lens 43. The spatial light modulator 30 is a phase modulating spatial light modulator, includes a plurality of two-dimensionally arrayed pixels, is capable of phase modulation in each of these pixels in a range of 4π or more, and presents a phase pattern to modulate the phase of light in each of the pixels. This phase pattern is produced by superimposing a blazed grating pattern for light diffraction and a phase pattern having a predetermined phase modulation distribution, and with a phase modulation range of 2π or more.