Achromatic Risley Prism Scanner Using Multi-Material Triplets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Risley prism scanners are limited to steering monochromatic beams due to wavelength-dependent deflection, restricting their use to narrow spectral bandwidths, making them unsuitable for achromatic systems.
Innovation Solution
A wide band achromatic beam scanning device using two multi-prism triplets, each composed of different optical materials (zinc sulfide, zinc selenide, and gallium arsenide) with optimized wedge angles, allowing all wavelengths to emerge in the same direction, mimicking monochromatic beam behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional Risley prism scanner is used to steer beams, then beam steering capability is achieved, but the spectral bandwidth is limited due to wavelength-dependent deflection
Solution Approach 1:
The single prism is segmented into multiple prisms (at least two) with different optical materials and wedge angles. Each prism segment handles a specific portion of the wavelength range, and their combined effect achieves wavelength-independent beam steering while expanding spectral bandwidth.
Solution Approach 2:
Different prisms are assigned different local qualities through the use of distinct optical materials (e.g., ZnS, ZnSe, GaAs) and different wedge angles. This local differentiation allows each prism to compensate for the dispersive effects of others at specific wavelength ranges, achieving overall achromatic performance.
2Adaptability or versatility
If a conventional Risley prism scanner is used, then monochromatic beam steering is achieved, but achromatic beam steering is not possible
Solution Approach 1:
The prism system is segmented into multiple prisms with different optical materials and wedge angles arranged in sequence. This segmentation allows the system to handle achromatic beams by compensating for wavelength-dependent deflection through the combined optical paths, achieving achromatic beam steering capability.
Solution Approach 2:
The system uses composite prism configurations made from different optical materials (e.g., ZnS, ZnSe, GaAs) with complementary dispersive properties. These composite material arrangements enable the system to cancel out wavelength-dependent effects while maintaining beam steering functionality.
3Adaptability or versatility
If multiple prisms with different optical materials are used, then achromatic beam steering is achieved, but device complexity increases
Solution Approach 1:
The prism system is divided into multiple segments with different optical materials and wedge angles. Each segment is optimized to handle specific wavelength ranges, and their sequential arrangement achieves achromatic beam steering while managing the complexity through systematic design.
Solution Approach 2:
The system achieves achromatic performance by varying key parameters including optical material selection (ZnS, ZnSe, GaAs), wedge angles, and prism dimensions. These parameter changes are optimized to compensate for wavelength-dependent deflection while maintaining a manageable number of components.
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 steering of achromatic beams as if they were monochromatic, overcoming the limitations of conventional Risley prism scanners by equalizing net dispersive effects across a wide spectral range.
Implementation Method 1
The relative position, wedge angle orientation, and optical material of each component is optimized such that wide band light transmitted through all of the components emerges with all wavelengths travelling in the same direction thereby equalizing net dispersive effects for all wavelengths
Data Source
AI summary
A system and method for scanning a wide band beam is presented. An apparatus includes a pair of prism triplets. Each prism triplet includes a first wedge prism, a second wedge prism and a third wedge prism all formed with different optical materials. In operation, a beam passing through the wide band team scanning apparatus first passes through the first, second and third wedge prisms of the first prism triplet. The beam then passes through the wedge prisms of the second prism triplet in a mirrored order (the third, then second, then first wedge prisms) than that of the first prism triplet. This apparatus with two prism triplets allows wide band light transmitted through it to emerge with its plurality of different wavelengths of light travelling in the same direction to equalize net dispersive effects each of different wavelengths.