System and method for generating broadband terahertz waves at any polarization angle

Abstract

The invention provides a system and method for generating broadband terahertz waves at any polarization angle, and the system comprises a signal generation device and a polarization conversion device, the signal generation device is used for generating pump light, the signal generation device comprises a focusing lens, the focusing lens is arranged on a light path of the pump light, and the polarization conversion device is used for converting the pump light to the polarization angle. The pump light is focused in the air to excite the air to form air plasma; the polarization conversion device comprises a first electric field generating device for generating a first electric field, a second electric field generating device for generating a second electric field and an electric field adjusting device, the first electric field and the second electric field intersect to form a synthetic electric field, and the air plasma forms terahertz waves through the synthetic electric field. According to the terahertz wave detector, the intensity of the two crossed electric fields is adjusted, so that the air plasma located in the synthetic electric field generates terahertz waves with any polarization angle, the intensity of the terahertz waves can be accurately controlled by adjusting the intensity of the electric fields, loss of the intensity of the terahertz waves cannot be caused, and therefore the detection effect of the terahertz wave detector is improved.

Description

technical field [0001] The present invention relates to the technical field of terahertz waves, in particular to a system and method for generating broadband terahertz waves with arbitrary polarization angles. Background technique [0002] Due to the particularity of its spectral position, terahertz waves have the characteristics of high penetration, low energy, sensitivity to polar molecules, and friendliness to non-metallic and non-polar materials. They have unique advantages in non-destructive testing and safety monitoring. Using the terahertz time-domain spectroscopy detection system, by changing the polarization direction of the incident and detection light, the imaging experiment of different polarization directions is carried out on the sample. Due to the low transmittance and large dispersion of many materials, the results of traditional direct imaging cannot be resolved, and it is difficult to achieve the expected effect. Therefore, it is necessary to process the re...

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Problems solved by technology

[0003] The present invention provides a system and method for generating broadband terahertz waves with arbitrary polarization angles, which is used to solve the problem of obtaining terahertz waves with different polarization angles by using wire grid polarizers or other terahertz polarizing devices in the prior art. Compared with the traditional method of generating terahertz waves, the present invention adjusts the strength of two intersecting electric fields and the vector direction of the two electric fields, so that the air plasma located in the synthetic electric field Generate terahertz waves with arbitrary polarization angles, and by adjusting the intensity of the electric field, the intensity of terahertz waves can be precisely controlled without loss to the intensity of terahertz waves, thereby improving the detection effect of terahertz wave detectors

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