Terahertz Oscillating Substrate Adhesive Cut-Off

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Solution Overview

Problem

Existing devices for oscillating terahertz waves using parametric effects face challenges in efficiently drawing the waves out of the crystal due to high refractive index and significant absorption, requiring optical means like prisms or gratings, which result in low intensity and propagation losses.

Innovation Solution

A device with a z-plate of a non-linear optical crystal as the oscillating substrate, adhered to a supporting body with an adhesive layer of lower refractive index, is designed to confine pump and idler waves, allowing terahertz waves to be oscillated and emitted without the need for external drawing means by creating a cut-off state for the substrate with respect to the terahertz wave, thus preventing absorption and reducing losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a z-plate or y-plate of LiNbO3 is used to oscillate terahertz waves by parametric effect, then terahertz waves can be generated with high temporal and spatial coherency, but the high refractive index of the crystal causes total internal reflection and makes it impossible to draw the terahertz wave into the air efficiently

Engineering Contradiction:

Improvecoherency of terahertz waveVSAvoidtotal internal reflection at crystal-air interface

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an optical means (prism or grating) as an intermediary component placed on the crystal surface to facilitate the extraction of terahertz waves from the high-refractive-index crystal into air, overcoming the total internal reflection barrier while preserving the coherency benefits of the LiNbO3 crystal

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the terahertz wave is drawn into the air using optical means like prism or grating on the crystal surface, then the terahertz wave can be emitted outside the crystal, but the process results in propagation losses and reduced intensity

Engineering Contradiction:

Improveemission of terahertz wave into airVSAvoidpropagation loss and intensity reduction

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent optimizes the parameters of the optical means (prism angle, grating period, positioning) to minimize propagation losses and maximize the intensity of the emitted terahertz wave, balancing the ability to extract the wave with the preservation of its energy

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the crystal thickness is increased to improve parametric oscillation efficiency, then terahertz wave generation efficiency is improved, but optical loss in the crystal increases significantly

Engineering Contradiction:

Improveoscillation efficiency of terahertz waveVSAvoidoptical loss in crystal

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent determines and applies an optimal crystal thickness parameter that balances two competing requirements: sufficient thickness to enable efficient parametric oscillation and generation of terahertz waves, while limiting the thickness to minimize optical absorption losses within the crystal

Inventive Principle:

Principle #35Parameter changes

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 high-efficiency generation and emission of terahertz waves with increased output power and reduced attenuation, eliminating the necessity for optical drawing means on the crystal surface, thereby enhancing the practical application of terahertz wave devices.

Implementation Method 1

the adhesive layer having a refractive index with respect to the pump wave lower than that of the oscillating substrate

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the adhesive layer having a refractive index with respect to the pump wave lower than that of the oscillating substrate

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

oscillating an electromagnetic wave having a frequency of 0.1 THz to 3 THz from pump and idler waves by parametric effect

Methodology Applied

Scientific EffectParametric oscillation:

Implementation Method 4

stimulated Raman scattering (referred to as Polariton stimulated scattering) is caused by Polariton, which is hybrid wave of optically active transverse wave lattice vibration (TO Phonon) and terahertz wave in a crystal

Methodology Applied

Scientific EffectStimulated Raman scattering:

Implementation Method 5

the oscillating substrate is cut-off with respect to the electromagnetic wave oscillated by parametric effect when the pump and idler waves propagate in parallel with the bottom face

Methodology Applied

Scientific EffectCut-off state:

Data Source

PatentUS8305679B2Electromagnetic wave oscillating devices

Publication Date: 2012.11.06 NGK INSULATORS LTD

AI summary

A device for oscillating an electromagnetic wave having a frequency of 0.1 THz to 3 THz from pump and idler waves by a parametric effect. The device includes a supporting body, an oscillating substrate made of a non-linear optical crystal, and an adhesive layer adhering the supporting body and oscillating substrate. The oscillating substrate includes an upper face, a bottom face and an incident face on which the pump wave is made incident. The oscillating substrate provides cut-off with respect to the electromagnetic wave oscillated by the parametric effect when the pump and idler waves propagate in parallel with the bottom face.