Slant-Stripe Periodically Poled Nonlinear Material for Terahertz Generation
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Solution Overview
Problem
Existing parametric devices face limitations in spectral coverage due to absorption within nonlinear media, and the non-collinear phase-matching technique restricts beam focusing, leading to increased absorption losses and reduced parametric gain.
Innovation Solution
The optical parametric device employs a slant-stripe-type periodically-poled nonlinear material with collinear pump and idler waves and a non-collinear signal wave, allowing for the selection and output coupling of one signal wave to minimize absorption, and incorporates dispersive components to suppress the higher gain/lower threshold solution, ensuring the signal wave exits at a critical angle less than the critical angle for total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-collinear phase-matching is used to reduce absorption, then spectral coverage is improved, but beam focusing is restricted and parametric gain is reduced
Solution Approach 1:
The patent segments the phase-matching process into two independent components: collinear phase-matching for the pump and idler waves to maximize parametric gain, and non-collinear phase-matching for the signal wave to minimize absorption. This segmentation allows each wave to be optimized independently for its specific function.
Solution Approach 2:
The patent applies different phase-matching geometries to different waves locally: collinear geometry for pump and idler waves where high gain is needed, and non-collinear geometry for the signal wave where absorption minimization is critical. This local optimization resolves the contradiction between gain and absorption.
2Adaptability or versatility
If non-collinear phase-matching is used to reduce absorption, then spectral coverage is improved, but beam focusing capability is reduced
Solution Approach 1:
The patent segments the phase-matching requirements by wave type: collinear phase-matching for pump and idler waves enables tight beam focusing, while non-collinear phase-matching for the signal wave enables spectral coverage extension. This segmentation allows both focusing and spectral coverage to be optimized independently.
Solution Approach 2:
The patent applies collinear phase-matching locally to pump and idler waves where beam focusing is essential for high gain, and non-collinear phase-matching locally to the signal wave where spectral coverage is the priority. This local differentiation resolves the contradiction between focusing capability and spectral coverage.
3Object-affected harmful factors
If absorption is reduced by non-collinear phase-matching, then spectral coverage is improved, but parametric gain is reduced
Solution Approach 1:
The patent segments the optical interaction into two independent phase-matching channels: collinear channel for pump and idler waves where parametric gain is maximized, and non-collinear channel for signal wave where absorption losses are minimized. This segmentation allows simultaneous optimization of both parameters.
Solution Approach 2:
The patent applies collinear phase-matching locally to pump and idler waves where high parametric gain is required, and non-collinear phase-matching locally to the signal wave where minimizing absorption is critical. This local optimization strategy resolves the contradiction between gain and absorption losses.
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 enhances spectral coverage by reducing absorption losses and achieving higher parametric gain, allowing for efficient generation and extraction of terahertz and long-wave infrared radiation, useful for spectroscopic analysis and material detection.
Implementation Method 1
generation of electro-magnetic radiation through a parametric-wave generation process
Implementation Method 2
a coherent beam of electromagnetic radiation is used to stimulate a non-linear process in a non-linear optical crystal, resulting in the division of the power/energy in the coherent pump wave into two generated waves
Implementation Method 3
the signal wave exits the nonlinear medium within a short distance and hence with reduced absorption... the signal wave exits at a critical angle less than the critical angle for total internal reflection
Data Source
AI summary
An optical parametric device comprising a slant-stripe periodically poled nonlinear material that is operable to generate signal in response to interaction with a pump wave, the non-linear interaction being such that the pump and idler waves are collinear and the signal wave is non-collinear relative to the pump and idler waves, wherein the slant-stripe non-linear material is able to generate two idler waves and two signal waves, and the device is adapted to allow for the selection and output coupling of a required one of the two signal waves.