Ultra-short Terahertz Pulse Generator Using Segmented Foils
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Solution Overview
Problem
Current methods for generating high-power ultra-short terahertz waves using coherent transition radiation with ultra-short electron beams face inefficiencies due to space charge repulsion and economic limitations from scaling up accelerators, requiring a more efficient technique to enhance energy conversion.
Innovation Solution
A method involving a series of thin foils arranged in one direction with spaced gaps, where ultra-short high-energy electron beams pass through, generating terahertz waves within these gaps, and the waves are propagated and combined to form a coherent wave front, enhancing generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of electrons in an electron bunch is increased to generate high-power terahertz waves using a single foil, then the power of terahertz waves increases, but space charge repulsion becomes excessive and accelerator scale and cost increase
Solution Approach 1:
The invention divides a single large electron bunch into multiple smaller electron bunches that pass through multiple foils sequentially. This segmentation reduces the space charge repulsion in each bunch while distributing the terahertz generation across multiple foils, achieving high power without excessive space charge effects or accelerator scaling
Solution Approach 2:
The invention combines the terahertz radiation from multiple foils by arranging them in sequence along the electron beam path. The terahertz waves generated at each foil are merged to produce high-power output, achieving the effect of using a large electron bunch without actually increasing the bunch size
2Power
If the number of electrons in an electron bunch is increased to generate high-power terahertz waves, then the power of terahertz waves increases, but the scale and capacity of accelerators must be increased
Solution Approach 1:
The system segments the terahertz generation process across multiple foils rather than requiring a single large electron bunch. This allows the use of a smaller, more economical accelerator while achieving high power through the combined output of multiple foils
Solution Approach 2:
The invention uses multiple copies of the same foil structure in sequence, where each foil generates terahertz radiation independently. This copying approach allows scaling of power output by adding more foils rather than increasing accelerator capacity
3Duration of action of moving object
If conventional transition radiation methods are used with ultra-short electron beams, then ultra-short terahertz pulses can be generated, but the generation efficiency remains extremely low
Solution Approach 1:
The invention segments the radiation generation process across multiple foils, with each foil contributing to the overall terahertz pulse. This segmentation maintains the ultra-short pulse duration while improving total energy conversion efficiency by distributing the interaction across multiple boundaries
Solution Approach 2:
The multiple foils are arranged in sequence to provide continuous terahertz generation along the electron beam path. This continuous action across multiple foils increases the total energy conversion while maintaining the ultra-short pulse characteristics
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 significantly increases the generation efficiency of ultra-short terahertz waves, allowing for higher energy pulses while reducing the need for large and costly accelerators, by leveraging the coherent transition radiation effect across multiple foils.
Implementation Method 1
Transition radiation is radiation emitted when a relativistic electron passes through a boundary between two media having different refractive indexes from each other. When the transition radiation meets a coherent condition, output and generation efficiency may also increase.
Data Source
AI summary
This specification relates to a terahertz pulse generator capable of generating ultra-short terahertz pulses by use of electron beams transported through a plurality of foils. The plurality of foils in a shape of disc are arranged in an overlapped state and form a conical shape that diameters of the disc-shaped foils sequentially decrease along a direction that the electron beam is transported. Coherent radiation, which is generated as the ultra-short electron beam is transported through the foils in respective spaced gaps of the foils, is propagated toward the outside of the disc-shaped foils and gathered with forming a conical wave surface at edges of the disc-shaped foils. This may result in enhancement of generation efficiency of the terahertz waves.