Abnormal enhancement of terahertz signal by using a hole

Huygens-Fresnel principle and half-wave method are usually used to explain the diffraction effect as the light passing through a hole. We present a new simple method to enhance the terahertz signal intensity by using a small hole. We found that in the terahertz time-domain spectroscopy, the terahertz signal enhances by 13.87% as a hole with certain size is put in a certain position of the terahertz beam path. This effect can be fully explained by using Huygens Fresnel principle. Therefore, in the condition of terahertz emitter and detector are unchanged, by using this method to enhance the terahertz signals is of great significance.

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