Wedge-Shaped Crystal Phase Compensation for Double-Pass Frequency Conversion
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Solution Overview
Problem
Existing frequency conversion devices using nonlinear optical crystals face inefficiencies due to phase mismatch between incoming and outgoing electromagnetic radiation, often requiring additional phase compensation elements that increase costs and introduce performance losses.
Innovation Solution
A device with a nonlinear optical crystal having a wedge-shaped end domain and a pivotable crystal holder, allowing adjustment of the optical path length to ensure phase matching between incoming and outgoing radiation without additional phase compensation elements, thereby optimizing conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional phase compensation elements are used to achieve phase matching, then phase matching accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the physical parameters of the nonlinear optical crystal by introducing a wedge angle at the end domain. This geometric parameter modification allows the optical path length to vary continuously, enabling phase matching to be achieved by adjusting the wedge angle rather than adding separate compensation elements. The wedge angle serves as a tunable parameter that directly controls the phase relationship between fundamental and harmonic waves.
Solution Approach 2:
The patent extracts the phase compensation function from separate external elements and integrates it directly into the nonlinear optical crystal structure itself. By incorporating the wedge-shaped end domain within the crystal, the phase compensation capability is built-in, eliminating the need for additional standalone compensation components and simplifying the overall device architecture.
2Measurement precision
If additional phase compensation elements are used to achieve phase matching, then phase matching accuracy is improved, but energy loss increases
Solution Approach 1:
The patent extracts the phase compensation function from separate external elements and integrates it directly into the nonlinear optical crystal structure itself. By incorporating the wedge-shaped end domain within the crystal, the phase compensation capability is built-in, eliminating the need for additional standalone compensation components and simplifying the overall device architecture.
Solution Approach 2:
The patent merges the phase compensation function with the nonlinear optical conversion function into a single integrated crystal structure. The wedge-shaped end domain performs both the frequency conversion and the phase compensation simultaneously, eliminating energy losses that would occur at interfaces between separate components and reducing the total number of optical elements in the system.
3Productivity
If the optical path length is adjusted to achieve phase matching, then conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent changes the physical parameters of the nonlinear optical crystal by introducing a wedge angle at the end domain. This geometric parameter modification allows the optical path length to vary continuously, enabling phase matching to be achieved by adjusting the wedge angle rather than adding separate compensation elements. The wedge angle serves as a tunable parameter that directly controls the phase relationship between fundamental and harmonic waves.
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 approach ensures approximate phase matching on both paths through the crystal, enhancing conversion efficiency without additional lossy elements, and is applicable to various nonlinear optical effects, including frequency doubling and four-wave mixing.
Implementation Method 1
nonlinear optical crystal having a first domain and an end domain... a portion of the input radiation is converted into output radiation during operation of the device
Implementation Method 2
the back reflector reflects the input radiation exiting the crystal through the second end facet and the output radiation exiting the crystal through the second end facet back into the crystal through the second end facet
Implementation Method 3
the spontaneous polarization of the crystal having a first orientation in the first domain and a second orientation in the end domain, the first orientation and the second orientation being different from one another... ensures approximate phase matching on both paths through the crystal
Data Source
Figure 1~2
AI summary
The present invention relates to a device for converting electromagnetic input radiation with a first frequency into electromagnetic output radiation with a second frequency different from the first frequency, the device comprising: a coupler, a crystal holder, a nonlinear optical crystal mounted on the crystal holder, the nonlinear optical crystal having a first domain and an end domain, wherein the spontaneous polarization of the crystal in the first domain has a first orientation and in the end domain a second orientation, the first orientation and the second orientation being different from each other, and wherein the crystal has a first end facet and a second end facet, the end domain being bounded by the second end facet and the end domain being wedge-shaped with a wedge angle, and a back reflector.wherein the coupler is designed and arranged such that, during operation of the device, the input radiation is injected into the crystal by the coupler through the first end facet, so that the input radiation is transmitted through the crystal and exits the crystal through the second end facet, wherein the crystal is designed and arranged such that a portion of the input radiation is converted into the output radiation during operation of the device, wherein the back reflector is designed and arranged such that, during operation of the device, the back reflector reflects the input radiation exiting the crystal through the second end facet and the output radiation exiting the crystal through the second end facet back into the crystal through the second end facet.so that the input radiation and the output radiation are transmitted through the crystal and exit the crystal through the first end facet. According to the invention, the crystal holder is designed such that the crystal holder is pivotable with the crystal about a pivot axis, wherein the end domain is wedge-shaped with the wedge angle in at least one plane perpendicular to the pivot axis.