Terahertz Near-Field Probe Imaging With Direct Current Signal Extraction
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Solution Overview
Problem
Conventional terahertz near-field imaging systems face issues with low signal-to-noise ratio due to the mixing of far-field signals and require complex optical path systems, which are sensitive to minor deviations leading to reduced signal strength.
Innovation Solution
A terahertz near-field imaging system using a metal probe to couple near-field signals into a current, transmitted via a transmission line to a back-end processor, eliminating the need for an optical path system and enhancing signal extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a complex optical path system is used to propagate near-field signals to the far field, then the near-field information can be transmitted, but the signal-to-noise ratio deteriorates due to mixing with far-field scattered signals
Solution Approach 1:
The patent extracts only the necessary near-field signal component from the total electromagnetic field by using a metal probe to directly couple and extract the near-field signal generated on the sample surface, eliminating the need to propagate mixed near-field and far-field signals through a complex optical path system. This extraction approach isolates the useful near-field information from harmful far-field scattered signals, thereby maintaining high signal-to-noise ratio while transmitting near-field information.
2Loss of information
If a complex optical path system with nanoscale-resolution displacement stage is used, then near-field signal propagation is achieved, but the device complexity increases and manufacturing cost rises
Solution Approach 1:
The patent replaces the complex mechanical optical path system with a direct electromagnetic coupling approach. Instead of using mirrors, lenses, and nanoscale displacement stages to propagate near-field signals through optical paths, the invention uses a metal probe to directly couple with the near-field signal on the sample surface and transmit it as a current signal through a simple transmission line to the backend processing unit, dramatically simplifying the device structure.
Solution Approach 2:
The patent extracts and eliminates the unnecessary complex optical path components from the system. By directly coupling the near-field signal through a metal probe and transmission line, the system removes the need for complicated optical elements, mirrors, and precision mechanical stages, thereby reducing device complexity and manufacturing cost while maintaining near-field signal propagation capability.
3Loss of information
If a complex optical path system is used for near-field signal extraction, then signal transmission is possible, but the manufacturing cost increases
Solution Approach 1:
The patent extracts and removes the expensive complex optical path components from the system architecture. By using a simple metal probe coupled with a transmission line to directly extract and transmit near-field signals, the invention eliminates the need for costly optical elements, precision mechanical stages, and complex alignment systems, thereby significantly reducing manufacturing cost while maintaining near-field signal transmission capability.
Solution Approach 2:
The patent replaces the expensive mechanical optical path system with a simpler electromagnetic coupling system. Instead of using costly optical components and precision mechanical stages required for optical path systems, the invention uses a metal probe and transmission line to directly transmit near-field signals, dramatically reducing manufacturing cost while achieving the same signal transmission function.
4Reliability
If a metal probe directly couples near-field signals into current, then the signal-to-noise ratio improves, but a new signal extraction method must be implemented
Solution Approach 1:
The patent replaces the complex optical-based signal extraction method with a direct electromagnetic coupling method using a metal probe. Instead of using optical paths, mirrors, and lenses to extract and propagate near-field signals, the invention uses a metal probe to directly couple the near-field signal into a current signal that can be transmitted through a simple transmission line to the backend processing unit, simplifying the signal extraction process while improving signal-to-noise ratio.
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 improves signal-to-noise ratio and simplifies the construction of the microscope, reducing manufacturing costs and simplifying signal processing by directly extracting high-quality near-field signals.
Implementation Method 1
a laser device for generating a femtosecond laser, where the femtosecond laser is divided into incident light and detection light by means of a beam splitter, the incident light is transmitted to an incidence unit, and the detection light is transmitted to a delay unit, is delayed, and is then transmitted to a photoconductive switch and triggers the photoconductive switch to be switched on
Implementation Method 2
the metal probe for coupling the near-field signal into a current signal on a surface of the metal probe, where the current signal is transmitted to a back end processing unit via the metal probe, a transmission line and the photoconductive switch
Data Source
Figure 1~2
AI summary
A terahertz near-field imaging system and method. The system includes: a laser device for generating a femtosecond laser, where the femtosecond laser is divided into incident light and detection light by means of a beam splitter, the incident light is transmitted to an incidence unit, and the detection light is transmitted to a delay unit, is delayed, and is then transmitted to a photoconductive switch and triggers the photoconductive switch to be switched on; the incidence unit for generating an incident signal under the excitation of the incident light, where the incident signal excites a metal probe to generate a local field, and the local field excites a sample in the detection direction of the metal probe to generate a near-field signal; the metal probe for coupling the near-field electromagnetic waves signal with a near-field current signal, where the current signal is transmitted to a back end processing unit via the metal probe, a transmission line and the photoconductive switch; and the back end processing unit for receiving and processing the current signal to obtain near-field information of a surface of the sample. According to the present invention, the metal probe is used for exciting and extracting the near-field signal from the surface of the sample in the form of a current, such that the signal-to-noise ratio and the signal strength of the near-field signal can be significantly improved, and a near-field optical path design is also greatly simplified.