Multi-band laser system using dichroic mirrors
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Solution Overview
Problem
Existing laser systems that use wavelength beam combining (WBC) methods are limited in producing a broader bandwidth output while maintaining high power and brightness, as they are designed for single narrow-bandwidth high-brightness output beams, and there is a need for a spectrally broad multi-band laser system with multiple high-brightness bands centered around a central wavelength.
Innovation Solution
A multi-band laser system is developed that combines radiation bands from multiple laser modules using a dispersive element and a partially-reflective output coupler, allowing for the creation of a multi-band beam with unique center wavelengths and spectral bandwidths, which are then overlapped and transmitted through a common optical path using dichroic mirrors to form a high-power, spectrally broad output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wavelength beam combining methods are used to produce single narrow-bandwidth high-brightness output beams, then high power and brightness are achieved, but broader bandwidth output cannot be obtained
Solution Approach 1:
The system segments the laser output into multiple wavelength bands, with each band generated by a separate laser module. Each module produces a narrow-band high-brightness beam, and these segmented bands are then combined using dichroic mirrors to form a multi-band output that maintains high brightness while achieving broader spectral coverage
Solution Approach 2:
Multiple narrow-band laser beams from different wavelength modules are merged into a single multi-band output beam using dichroic mirrors. The combining region overlaps these beams spatially and spectrally, creating a unified high-power multi-band beam that preserves the high brightness of individual bands while extending the spectral bandwidth
2Adaptability or versatility
If multiple laser modules are combined to produce broader bandwidth output, then spectral bandwidth is improved, but system complexity increases
Solution Approach 1:
The dichroic mirrors serve multiple functions: they combine different wavelength bands into a single output path, provide optical feedback to multiple laser modules simultaneously, and maintain spatial overlap of beams. This multi-functionality reduces the need for separate combining and feedback mechanisms for each module, thereby reducing overall system complexity
Solution Approach 2:
The dichroic mirrors act as intermediary optical elements that facilitate the combination of multiple laser bands and the distribution of feedback. Rather than requiring direct interaction between multiple laser modules, the mirrors mediate the coupling and combining processes, simplifying the system architecture
3Volume of moving object
If a common optical path is used to combine multiple radiation bands, then spatial compactness is achieved, but alignment precision requirements increase
Solution Approach 1:
The partially-reflective output coupler provides optical feedback to multiple laser modules through the common optical path. This feedback mechanism helps maintain beam alignment and stability, compensating for potential misalignments and reducing the stringency of alignment precision requirements during assembly and operation
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 system achieves a scalable high-power, high-brightness multi-band output with spectral bandwidths ranging from sub-nanometers to microns, suitable for various applications including commercial and military uses, by effectively combining radiation bands from multiple laser modules into a single free-space cavity system.
Implementation Method 1
The dispersive element is placed at the region of overlap, receives the radiation bands, and transmits the bands as a combined multi-band beam
Implementation Method 2
The dichroic mirrors receive the first and second bands and form a multi-band beam by transmitting each band along an optical path
Implementation Method 3
The partially-reflective output coupler transmits the multi-band beam while reflecting a portion of the multi-band beam back into each dispersive element
Data Source
AI summary
A multi-band scalable output power laser system configured to have high brightness and output power in each band is accomplished by combining multiple laser modules, with each producing at least one band, and wherein at least one of the laser modules is based on a wavelength beam combining (WBC) system, into a multi-band free-space cavity.