Polychromatic Light Device Non-Linear Frequency Conversion
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Solution Overview
Problem
Current light sources for generating broad spectrum white light are either inefficient, bulky, expensive, or have short lifespans, and fail to provide a spatially coherent beam with sufficient power and low divergence.
Innovation Solution
A device using optical pumping means to deliver radiation with multiple excitation wavelengths and non-linear light/matter interaction in a microstructured optical fibre, generating polychromatic light with a continuous spectrum, high power, and transverse monomodal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If incandescent or arc sources are used to generate broad spectrum white light, then a continuous emission spectrum is achieved, but the luminance is weak, the light emission is isotropic (cannot be focused), the sources are large in size, have short life, and generate excessive heat with poor efficiency
Solution Approach 1:
The patent replaces thermal radiation mechanisms (incandescent/arc sources) with a cold light generation mechanism using frequency conversion in non-linear optical materials. A laser source at wavelength λ pumps a non-linear crystal to generate photons at λ/2, avoiding thermal effects entirely and achieving high luminance without excessive heat generation.
Solution Approach 2:
The patent changes the fundamental parameter of light generation from thermal radiation to non-linear optical frequency conversion. By using a laser pump source and non-linear crystal, the system transforms the physical mechanism from thermal to quantum optical, achieving high efficiency and directed emission.
2Volume of moving object
If multiple monofrequency laser diodes are placed in parallel to generate different wavelengths, then the dimensions are reduced, but the spectrum is not continuous, partition noise is high, and intensity variations occur between diodes
Solution Approach 1:
The patent segments the broad spectrum generation into two parts: a continuous narrow-line laser source provides the base wavelength, and a non-linear crystal generates the second harmonic. This segmentation allows continuous spectral output without the discontinuities of multiple discrete laser diodes.
Solution Approach 2:
The single laser source serves multiple functions: it directly provides photons at wavelength λ and, through frequency conversion in the non-linear crystal, provides photons at wavelength λ/2. This universal approach eliminates the need for multiple separate laser diodes and their associated intensity variation problems.
3Illumination intensity
If a titanium/sapphire laser pumps a microstructured optical fibre in pulsed regime to generate different wavelengths, then polychromatic light is produced, but the source is very expensive and very bulky, ruling out integrated product use
Solution Approach 1:
The patent extracts only the essential function of broad spectrum generation from the complex titanium/sapphire laser system. By using a simpler laser source combined with frequency conversion in a non-linear crystal, the invention removes the bulk and cost while retaining the polychromatic light generation capability.
Solution Approach 2:
The patent replaces the expensive, complex titanium/sapphire laser system with a more affordable, simpler laser source and non-linear crystal combination. This substitution reduces cost and complexity while achieving the same functional outcome of generating polychromatic light.
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 provides a highly efficient, compact, and cost-effective source of white light with improved spectral broadening, reduced noise, and increased power, suitable for various applications including metrology, microscopy, and spectroscopy.
Implementation Method 1
light-guiding means arranged to deliver polychromatic light at an output when excited by the radiation in a non-linear light/matter interaction regime
Implementation Method 2
the frequency conversion means may be produced in the form of one or more frequency doublers, optionally of the non-linear crystal type, the second excitation wavelength thus being twice as small as the first
Data Source
AI summary
A dedicated polychromatic light generating device including optical pumping devices used to deliver radiation with at least two different excitation wavelengths and a light-guiding device used to deliver polychromatic light at an output when excited by the radiation in a non-linear interaction regime.