Beam-Shaping Device Using Dual Phase-Modulation SLMs
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Solution Overview
Problem
Conventional beam shaping devices struggle to arbitrarily change the intensity distribution of output light, limiting their ability to convert input light into desired cross-sectional shapes and intensity distributions, such as from Gaussian to top-hat or circular to square.
Innovation Solution
A beam shaping device comprising two phase-modulation type spatial light modulators, where the first modulator displays a phase pattern to approximate the desired intensity distribution, and the second modulator further adjusts the phase to achieve the desired output shape and intensity, allowing for arbitrary control over both phase and intensity distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a phase-modulation type spatial light modulator is used to hold down optical loss, then optical loss is reduced, but the device cannot perform intensity modulation and thus cannot convert input light into arbitrary cross-sectional shapes and intensity distributions
Solution Approach 1:
The spatial light modulator is divided into two separate devices: the first SLM performs intensity modulation by diffracting light into specific orders, while the second SLM performs phase modulation. This segmentation allows each device to specialize in one function, enabling both intensity and phase control without using an amplitude-modulating SLM that would cause optical loss.
Solution Approach 2:
The first spatial light modulator acts as an intermediary between the input light and the second spatial light modulator. It converts the input light's intensity distribution into a desired pattern by diffracting light, and the second SLM then modifies the phase of this diffracted light. This intermediary approach enables intensity control without direct absorption, reducing optical loss.
2Manufacturing precision
If a homogenizer with etched glass lenses is used to convert Gaussian intensity distribution to top-hat distribution, then intensity distribution conversion is achieved, but the device cannot arbitrarily change the intensity distribution of output light
Solution Approach 1:
The system uses programmable spatial light modulators with liquid crystal displays that can be dynamically reconfigured through electrical signals. Unlike fixed etched glass lenses, the phase patterns and diffraction gratings can be changed in real-time, allowing arbitrary intensity and phase distributions to be achieved without manufacturing new optical components.
Solution Approach 2:
The invention changes the control parameter from fixed physical structures to electrical signals. By modifying the voltage applied to each pixel of the spatial light modulators, the system can dynamically adjust diffraction patterns, phase distributions, and intensity profiles, enabling arbitrary beam shaping without physical reconfiguration.
3Adaptability or versatility
If two spatial light modulators are used to achieve arbitrary intensity and phase control, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system combines intensity modulation and phase modulation functions into a unified two-SLM architecture. The first SLM handles intensity distribution through diffraction, while the second SLM handles phase distribution, and both work together in sequence to achieve complete beam shaping control in a single integrated system.
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
Enables the conversion of input light into output with arbitrary cross-sectional shapes and intensity distributions, enhancing light use efficiency and flexibility in applications like laser processing and microscopy.
Implementation Method 1
a first phase modulation unit (12) which is composed of a phase-modulation type spatial light modulator, and displays a first phase pattern for modulating a phase of input light
Implementation Method 2
a second phase modulation unit (14) which is composed of a phase-modulation type spatial light modulator, displays a second phase pattern for further modulating a phase of light phase-modulated by the first phase modulation unit
Data Source
AI summary
A beam shaping device includes a first phase modulation unit including a phase-modulation type SLM, and displaying a first phase pattern for modulating a phase of input light, a second phase modulation unit including a phase-modulation type SLM, being optically coupled to the first phase modulation unit, and displaying a second phase pattern for further modulating a phase of light phase-modulated by the first phase modulation unit, and a control unit providing the first and second phase patterns to the first and second phase modulation units, respectively. The first and second phase patterns are phase patterns for approximating an intensity distribution and a phase distribution of light output from the second phase modulation unit, to predetermined distributions.