Parametric Generation Using Non-Collinear Intersecting Cavities
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Solution Overview
Problem
Existing parametric devices face limitations in extending spectral coverage due to absorption within non-linear materials, which restricts the generation of electromagnetic radiation to specific wavelengths, and require high-energy lasers and complex configurations for efficient operation.
Innovation Solution
A parametric device with a non-linear material where the pump and idler waves are non-collinear, allowing for broad and continuous tuning of the signal wave while maintaining overlap and lateral walk-off, reducing the pump power required to reach oscillation threshold, and using a cavity resonant at the pump wavelength to optimize the interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a non-linear material is used for parametric generation, then radiation of different wavelengths can be produced, but absorption within the material limits the spectral coverage
Solution Approach 1:
The patent transitions from collinear to non-collinear wave propagation, changing the spatial dimension of interaction. The pump, signal, and idler waves propagate at different angles, with the signal wave exiting laterally from the non-linear material. This dimensional change allows the signal wave to rapidly leave the interaction region, minimizing absorption path length and enabling extended spectral coverage.
2Adaptability or versatility
If non-collinear phase matching is used to reduce absorption, then spectral coverage is improved, but the radial extent of beams must be limited which reduces parametric gain
Solution Approach 1:
The patent employs non-collinear phase matching where pump, signal, and idler waves propagate at different angles. The signal wave exits laterally from the non-linear material, rapidly leaving the interaction region. This dimensional approach minimizes absorption while maintaining adequate parametric gain through optimized beam geometry and overlap in the interaction region.
3Power
If high-energy lasers are used to achieve efficient parametric generation, then oscillation threshold is reached, but the device becomes less compact and portable
Solution Approach 1:
The non-collinear configuration with lateral signal wave exit reduces the required pump power by minimizing absorption losses. This allows efficient parametric generation with lower energy lasers, enabling more compact and portable device designs while maintaining oscillation threshold requirements.
4Power
If the signal wave propagates collinearly with the pump wave, then interaction efficiency is maximized, but absorption increases and spectral coverage is limited
Solution Approach 1:
The patent adopts non-collinear phase matching where the signal wave propagates at a different angle than the pump wave, exiting laterally from the non-linear material. This spatial separation reduces the path length of the signal wave through the absorbing material, minimizing absorption losses while maintaining adequate interaction efficiency through optimized beam overlap in the interaction region.
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 configuration enables efficient generation of electromagnetic radiation across a wider spectral range with reduced pump power requirements, allowing for compact and portable devices while maintaining mechanical stability and tunability.
Implementation Method 1
a non-linear material when pumped by light energy produces radiation of different wavelengths to that of the pump energy
Implementation Method 2
Parametric devices are flexible and convenient sources of widely-tunable coherent radiation... a coherent beam of electromagnetic radiation referred to as the pump wave is used to stimulate a non-linear process in a non-linear (optical) material, resulting in the division of the energy/power in the coherent pump into two generated waves
Implementation Method 3
a cavity resonant at the pump wavelength to optimize the interaction
Implementation Method 4
using non-collinear phase matching in such a way as to cause the wave subject to absorption to rapidly walk out from the non-linear material in a direction that is substantially lateral to the propagation direction of the pump wave
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A parametric device having a non-linear material (4) for generating an idler wave and a signal wave (16) in response to a pump wave (14), the pump, idler and signal waves being non-collinear, the device having a cavity (10, 11) resonant at the pump wavelength and means for varying the angle between the propagation directions of the pump and idler waves.