Terahertz Illumination Source With Incoherent Beam Array
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Solution Overview
Problem
Existing terahertz illumination sources emit coherent radiation, leading to speckled images in terahertz imaging, and have limitations such as low lifetime, high-voltage requirements, low efficiency, and complex manufacturing processes, with limited capability to reduce coherence without external optical scrambling devices.
Innovation Solution
A terahertz illumination source comprising a surface with terahertz radiation emitting elements and a control signal generator that supplies control signals to emit individual terahertz radiation beams with controlled coherence properties, using high electron-mobility semiconductor materials like silicon-germanium, and incorporating beam shaping elements to form a terahertz illumination beam with reduced coherence and increased beam shaping capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If coherent terahertz radiation is used for illumination, then the illumination intensity is sufficient, but the image quality deteriorates due to speckle noise
Solution Approach 1:
The patent divides a single coherent terahertz source into multiple independent emitting elements arranged in an array. Each element emits terahertz radiation independently, and by controlling the phase and amplitude of each element, the system achieves spatial coherence reduction while maintaining sufficient illumination intensity through constructive interference in the far field.
Solution Approach 2:
The patent changes the coherence parameter of the terahertz illumination by using multiple emitting elements with independently controllable phases. By varying the phase differences between elements, the system transforms the coherence property of the illumination beam, reducing spatial coherence to eliminate speckle noise while preserving temporal coherence for maintaining illumination intensity.
2Power
If vacuum-electron devices are used as terahertz sources, then high power output is achieved, but device complexity and reliability worsen due to vacuum tube requirements and liquid cooling
Solution Approach 1:
The patent replaces vacuum-electron devices with semiconductor-based terahertz emitting elements. This substitution eliminates the need for vacuum tubes, high-voltage power supplies, and liquid cooling systems, thereby reducing device complexity while maintaining the ability to generate high power terahertz radiation through electronic means.
3Object-affected harmful factors
If moving path-dispersive optical elements are used to reduce coherence, then coherence is reduced, but ease of operation worsens due to moving parts
Solution Approach 1:
The patent replaces mechanical moving optical elements with electronically controlled phase modulation of multiple fixed emitting elements. The coherence reduction is achieved through electronic phase control rather than mechanical movement, eliminating moving parts and improving ease of operation while maintaining the ability to reduce spatial coherence.
4Object-affected harmful factors
If external optical scrambling devices are used to reduce coherence, then coherence is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the coherence control function from external optical scrambling devices and integrates it directly into the illumination source structure. By incorporating multiple independently controllable emitting elements within the source itself, the system achieves coherence reduction without requiring separate external optical scrambling components, thereby reducing overall device complexity.
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
The solution provides terahertz imaging with reduced coherent noise and improved image quality, enabling efficient and high-volume automated manufacturing, and overcoming the limitations of existing sources by inherently reducing coherence without external optical scrambling devices.
Implementation Method 1
A terahertz (THz) illumination source is a device capable of emitting electromagnetic radiation of frequency ranging from 0.1 THz to 10 THz
Data Source
AI summary
There is described a terahertz illumination source for terahertz imaging. The terahertz illumination source generally has: a surface; a plurality of terahertz radiation emitting elements mounted to said surface; a plurality of individual beam shaping elements each being optically coupled to a respective one of said terahertz radiation emitting elements; a collective beam shaper optically coupled to at least some of said individual beam shaping elements; and a control signal generator communicatively coupled to said terahertz radiation emitting elements, said control signal generator supplying a plurality of control signals to said terahertz radiation emitting elements, said terahertz radiation emitting elements emitting a plurality of individual terahertz radiation beams being collected and redirected successively by said individual beam shaping elements and said collective beam shaper, said terahertz radiation emitting elements and/or said control signals being configured so that said individual terahertz radiation beams are incoherent with respect to one another.