Device and method for improving THz-ATR imaging resolution and performance

Abstract

The invention discloses a device and a method for improving THz-ATR imaging resolution and performance. According to the method, continuous terahertz waves emitted by a terahertz radiation source are converted into sine waves through a chopper, the sine waves enter a terahertz wave spectroscope and are divided into two beams, one beam is reflected light, and the other beam is transmitted light which serves as signal light for detecting sample information; the signal light sequentially passes through a first terahertz wave reflector, a first off-axis parabolic mirror, a solid immersion ATR lens, and a sample holder, the signal light generates total reflection at the sample holder-sample interface, then emits from the solid immersion ATR lens, the emitted light passes through a second off-axis parabolic mirror and a second terahertz wave reflector, and then is received by a second terahertz detector. A computer controls the sample holder to move, collects signals received by the terahertz detector and analyzes and processes data. According to the invention, the resolution of attenuated total reflection type imaging is obviously improved, the problem of small effective imaging area caused by focus offset in a traditional attenuated total reflection type system can be solved, and high-sensitivity and high-resolution terahertz imaging of a large-size sample can be obtained.

Description

technical field [0001] The invention relates to the field of terahertz imaging, in particular to a device and method for improving the resolution and performance of THz-ATR imaging. Background technique [0002] Terahertz (Terahertz, referred to as THz, 1THz = 10 12 Hz) wave is an electromagnetic wave with a frequency between 0.1 and 10 THz, which has unique physical characteristics such as fingerprinting, safety and water sensitivity. This allows terahertz technology to be applied to many fields such as material property research, safety testing, and biomedical testing. As one of the research hotspots of terahertz-related technologies, terahertz imaging has achieved rapid development in the past few decades because of its unique advantages such as label-free, high sensitivity, fast and accurate. [0003] Terahertz imaging technology can be divided into near-field imaging and far-field imaging. Among them, the near-field imaging of terahertz waves can break through the li...

AI Technical Summary

Problems solved by technology

The following two methods are usually used to improve the imaging resolution: increasing the numerical aperture of the focusing lens in the imaging system, and using a large-aperture off-axis parabolic mirror; the former introduces additional wavefront aberrations while improving the resolution, resulting in a decrease in imaging quality ; Although the latter can correct the phase difference, it also faces problems such as overlapping of incident light and focused beam, and limited imaging area, and the improvement of resolution by the above method still cannot meet the requirements of high-resolution imaging

In addition, in the field of THz-ATR imaging, the imaging area based on prism scanning is mainly determined by the size of the ATR prism. The resolution will decrease rapidly when the prism is in the center; another scanning imaging method in which the sample holder is separated from the ATR prism is limited by the low numerical aperture of the traditional ATR prism, resulting in a lower system resolution

Therefore, the current high resolution and large imaging area cannot be achieved at the same time. At this stage, there is an urgent need for a method and device that can greatly increase the resolution and imaging area at the same time while ensuring the imaging quality to meet the high imaging requirements of in vivo biological tissues or other liquid samples. Sensitivity, high resolution, large area imaging needs

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