NLFC Device Optimizing Convergence Half-Angle for Walkoff
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Solution Overview
Problem
Conventional devices fail to perform nonlinear frequency conversion (NLFC) efficiently for non-diffraction-limited input beams in NLFC components that exhibit walkoff, as existing methods do not provide suitable focusing parameters for high efficiency in such configurations.
Innovation Solution
A new method is developed to identify suitable convergence half-angles for non-diffraction-limited input beams in NLFC components with walkoff, using the equation P(z') ∝ ∫∫ exp(-α^2 l^2) dE1^2 exp(jk1z) exp(jk2z) ∫∫ exp(-α1^2 z) exp(-jβx^2) ∫∫ exp(-α2^2 z) exp(-jβy^2) to calculate the power of frequency-doubled light, allowing for high-efficiency NLFC by optimizing the convergence half-angles φx and φy based on beam quality factors and walkoff angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional focusing methods are used for non-diffraction-limited input beams in NLFC components with walkoff, then the device complexity is reduced, but the NLFC efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the convergence half-angles (φx, φy) of the input beam based on the beam quality factors (Mx, My) and walkoff angle (ρ). The optimized parameters enable high-efficiency NLFC for non-diffraction-limited beams, transforming the system from using standard diffraction-limited parameters to tailored parameters that account for actual beam quality and walkoff effects.
2Productivity
If the convergence half-angle is optimized based on beam quality factors and walkoff angle, then the NLFC efficiency is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-calculating the optimal convergence half-angles (φx, φy) based on the beam quality factors (Mx, My) and walkoff angle (ρ) before the NLFC process. This allows the system to start with optimized parameters rather than requiring real-time adjustment during operation, improving efficiency while maintaining operational simplicity.
3Power
If standard diffraction-limited beam parameters are used, then the ease of manufacture is improved, but the power of frequency-doubled light deteriorates
Solution Approach 1:
The patent applies parameter changes by specifying non-standard convergence half-angles (φx, φy) that are calculated from beam quality factors (Mx, My) and walkoff angle (ρ), rather than using standard diffraction-limited parameters. This enables the system to achieve high power output for frequency-doubled light while working with practical non-diffraction-limited beams from common laser sources.
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 enables high-efficiency NLFC, as demonstrated by experimental verification, achieving significantly higher output power compared to conventional methods, particularly in generating ultraviolet light using β-BaB2O4 crystals for SHG.
Implementation Method 1
light of a first frequency (f 1 ) passes through a material with a non-zero second order nonlinear susceptibility, and some or all of the input light is converted into generated light with a second frequency (f 2 ), where f 2 = 2f 1 . This process is commonly referred to as 'second harmonic generation' (SHG)
Implementation Method 2
an optical component configured to converge a non-diffraction limited input beam into the NLFC component
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A nonlinear frequency conversion (NLFC) component (26) is incorporated into a light source (20). The light source includes a light emitting element (21) that emits a non-diffraction limited input light beam, and the NLFC component that exhibits walkoff and performs an NLFC process, such as second harmonic generation. An optical component (25) is configured to converge the non-diffraction limited input beam into the NLFC component with a determined convergence half-angle. The convergence half-angle in air in a non-walkoff plane of the NLFC component is larger than a convergence half-angle angle for diffraction-limited light. Said convergence half-angle may be a multiple, ε×M, multiplied by the convergence half-angle value for diffraction-limited light, wherein ε has a value between a lower value equal to the larger of 0.4 and 1M and an upper value of 5.0, where M is the square root of the beam quality factor for the non-diffraction limited light.