Terahertz material micro-nano defect detection device and method based on multi-frequency point information fusion

Abstract

The invention provides a terahertz material micro-nano defect detection device and method based on multi-frequency point information fusion. The device comprises a microwave excitation source, a terahertz transceiver module, a mirror surface combination module, a nano probe, an oscillation signal source, a lock-in amplifier and an upper computer, the microwave excitation source is used for generating an input signal input into the terahertz transceiver module and a frequency mixing signal input into the lock-in amplifier; the terahertz transceiver module is used for continuously radiating terahertz waves and receiving an evanescent signal locally enhanced and modulated by the nanoprobe; the mirror surface combination module is used for tightly coupling terahertz wave beams radiated by the terahertz receiving and transmitting module at the tip of the nanoprobe and reflecting an evanescent signal which is locally enhanced and modulated by the nanoprobe back to the terahertz receiving and transmitting module; and the oscillation signal source is used for generating a first signal for controlling the nanoprobe and a second signal input into the lock-in amplifier.

Description

technical field [0001] The invention belongs to the technical field of terahertz testing, and in particular relates to a micro-nano defect detection device and method for terahertz materials based on multi-frequency point information fusion. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] Based on the application needs of material micro-nano defect detection, as an emerging micro-nano defect detection analyzer that can break through the diffraction limit, the resolution of the scattering terahertz microscopic imager is only related to the size of the micro-probe in the system, and is not affected by it. The restriction of the incident light wavelength is the most promising micro-nano defect detection analyzer at present. However, most of the current scattering terahertz microscopic imagers are based on optical sources, which are limited b...

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Problems solved by technology

However, most of the current scattering terahertz microscopic imagers are based on optical sources, which are limited by the test mechanism. The performance of optical sources is greatly affected by the environment, the terahertz signal energy is weak, and the signal-to-noise ratio is poor, which is difficult to meet the test requirements.

[0004] Chinese invention patent application 201810970798.0 discloses a scattering terahertz near-field microscope based on radio frequency electronics. It is not difficult to find that this invention only uses terahertz point-frequency continuous The Hertz signal fusion function cannot obtain more physical and chemical information of materials, and the local enhancement characteristics of the evanescent field are subject to the relationship between the length of the nanoprobe and the wavelength, which is usually a nanoprobe with a large aspect ratio that is an integer multiple of 1 / 2 wavelength. For long-wavelength terahertz waves, such as terahertz waves in the 0.1THz frequency band (wavelength is 3mm), in order to obtain a strong local enhancement effect, the length of the nanoprobe should be about 1.5mm, and the aspect ratio is too large, making it extremely difficult to process. Large, difficult to control, generally speaking, the imaging quality of single-frequency points is poor, and the detection accuracy of micro-nano defects is poor

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