Terahertz Wave Extraction Prism for Nonlinear Crystal Power

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Solution Overview

Problem

Current terahertz wave generation devices face challenges in achieving high output power due to limitations in refractive index matching and wave propagation, leading to inefficient emission and reflection of terahertz waves.

Innovation Solution

The electromagnetic wave emission device incorporates a nonlinear MgO-doped LN crystal with a protruded optical waveguide and a prism structure, optimizing refractive index matching and wave propagation by using a buffer layer and a prism with a specific tilted angle to enhance terahertz wave extraction and reduce reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional terahertz wave generation device is used, then the device structure is simple, but the output power of terahertz waves is low due to inefficient emission and reflection

Engineering Contradiction:
Improveoutput power of terahertz wavesVSAvoiddevice structure complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The device is divided into distinct functional segments: a nonlinear crystal section for terahertz wave generation, a light incident section for excitation light input, and an electromagnetic wave extraction section for terahertz wave output. This segmentation allows each section to be optimized independently, improving overall terahertz output power while maintaining manageable device complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary structure (the electromagnetic wave extraction section with specific refractive index) that mediates between the nonlinear crystal and the external environment. This intermediary enables efficient coupling and extraction of terahertz waves, resolving the contradiction between simple structure and high output power by providing a specialized interface for wave extraction

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If refractive index matching is not optimized, then the device structure is simple, but wave propagation is inefficient leading to low terahertz emission

Engineering Contradiction:
Improveterahertz wave emission efficiencyVSAvoidrefractive index optimization complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent systematically changes the refractive index parameter of the electromagnetic wave extraction section to achieve optimal matching with the nonlinear crystal. By adjusting this key parameter, the device achieves efficient terahertz wave propagation and emission without requiring complex structural modifications, thus improving emission efficiency while controlling optimization complexity

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the terahertz wave direction is displaced from the optimal path, then the device should be robust to displacement, but conventional devices show reduced output power

Engineering Contradiction:
Improverobustness to direction displacementVSAvoidterahertz wave output power
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The electromagnetic wave extraction section is designed with dynamic characteristics that allow it to adapt to variations in terahertz wave propagation direction. The specific structural configuration enables the extraction section to effectively couple with terahertz waves even when their direction deviates from the optimal path, maintaining robust output power while providing adaptability to directional displacement

Inventive Principle:
Principle #15Dynamics

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 increases the output power of terahertz waves by ensuring efficient transmission and extraction, even when the terahertz wave direction is displaced from the optimal path, thereby overcoming previous limitations in terahertz wave generation.

Implementation Method 1

a broadband terahertz wave generation method by means of a difference frequency terahertz wave generation using the Cerenkov radiation has been proposed

Methodology Applied
Scientific EffectCerenkov radiation: Cherenkov Effect

Implementation Method 2

The incident excitation light having the two wavelengths induces nonlinear polarization in the MgO-doped LN crystal

Methodology Applied
Scientific Effectnonlinear polarization:

Implementation Method 3

a prism with a specific tilted angle to enhance terahertz wave extraction and reduce reflection

Methodology Applied
Scientific Effectrefraction: Refraction

Data Source

PatentEP2657758B1Electromagnetic wave emission device
Publication Date: 2018.01.10 ADVANTEST CORP
  • EP2657758B1 patent drawingFigure 1
  • EP2657758B1 patent drawingFigure 2
  • EP2657758B1 patent drawingFigure 3

AI summary

According to the present invention, an electromagnetic wave emission device includes a nonlinear crystal having an optical waveguide; and a prism including an electromagnetic wave input surface and an electromagnetic wave transmission surface. The electromagnetic wave transmission surface includes a rotation surface which is a trajectory of a tilted line segment rotated about a central axis of the electromagnetic wave input surface, the tilted line segment being tilted with respect to the central axis. The tilted line segment and the central axis are on the same plane. The central axis is in parallel to an extending direction of the optical waveguide. The central axis passes through a projection of the optical waveguide into the electromagnetic wave input surface.