Nonlinear Crystal Optical Arrangement for Incoherent Light

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Solution Overview

Problem

Existing laser systems are unable to process incoherent light effectively, leading to limitations in imaging spatially extended sources and requiring energy-inefficient methods to produce high-quality laser beams.

Innovation Solution

An arrangement comprising a focusing system, a cavity with an intra-cavity laser beam, and a quasi-phase matched nonlinear crystal that interacts with focused incoherent electromagnetic radiation to produce processed radiation in a different wavelength interval, enabling imaging and improving beam quality through sum or difference frequency generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a prior art laser system with nonlinear crystal is used for wavelength conversion, then wavelength conversion can be achieved, but the system cannot process incoherent light from spatially extended sources

Engineering Contradiction:
Improvecapability to process incoherent lightVSAvoidsystem performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a scanning unit as an intermediary component that sequentially directs light from different spatial positions of the extended source to the nonlinear crystal. This mediator enables the system to accept incoherent light from spatially extended sources by converting the spatial distribution into temporal sequence, allowing each point source to be processed individually while maintaining overall system functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If spatial filtering through pinhole or coupling to single-mode fiber is used to produce high quality laser beam, then beam quality is improved, but significant power loss occurs

Engineering Contradiction:
Improvebeam qualityVSAvoidpower loss
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical spatial filtering approach (pinholes and single-mode fibers) with a scanning system that uses a nonlinear crystal for frequency conversion. Instead of physically blocking and selectively transmitting beams, the system uses a scanning mirror to sequentially direct different spatial positions to the crystal, achieving beam quality improvement through controlled spatial selection without the energy loss of physical filtering.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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

This solution allows for efficient imaging and high-quality beam generation from incoherent sources, overcoming previous limitations by achieving high conversion efficiency and improving spatial quality of the processed radiation.

Implementation Method 1

The nonlinear crystal is configured to be quasi phase matched for conversion of the incoming incoherent electromagnetic radiation in the first wavelength interval to the processed electromagnetic radiation in the second wavelength interval

Methodology Applied
Scientific EffectSum frequency generation: Second Harmonic Generation

Implementation Method 2

by interaction with the intra-cavity laser beam provide processed electromagnetic radiation... through sum or difference frequency generation

Methodology Applied
Scientific EffectDifference frequency generation: Second Harmonic Generation

Implementation Method 3

a focusing arrangement for focusing the incoming incoherent electromagnetic radiation

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP2319141B1Optical arrangement and method
Publication Date: 2018.08.22 DANMARKS TEKNISKE UNIV
  • EP2319141B1 patent drawingFigure 1~2
  • EP2319141B1 patent drawingFigure 3a~4b
  • EP2319141B1 patent drawingFigure 5~6d

AI summary

Processing of incoherent electromagnetic radiation is described, said incoming incoherent electromagnetic radiation comprising radiation in a first wavelength interval. An arrangement comprises a focusing arrangement for focusing the incoming incoherent electromagnetic radiation, a first cavity configured to comprise an intra cavity laser beam, a nonlinear crystal arranged in the first cavity such that it is capable of receiving the focused incoherent electromagnetic radiation and, in dependence on the spatial overlap between the focused incoherent electromagnetic radiation and the intra-cavity laser beam, by interaction with the intra-cavity laser beam provide processed electromagnetic radiation, said processed electromagnetic radiation comprising radiation in a second wavelength interval. In other words, such an arrangement is capable of enabling imaging, e.g. by utilizing a detector that is sensitive in the second wavelength interval, a source of radiation that emits incoherently in a first wavelength interval.