Frequency selective surface-based polarization-adjustable terahertz filter

Abstract

The invention provides a frequency selective surface-based polarization-adjustable terahertz filter. The frequency selective surface-based polarization-adjustable terahertz filter is characterized bycomprising a substrate and at least one frequency selective surface unit, wherein the at least one frequency selective surface unit is fixed on the substrate, is periodically arranged in a two-dimensional way and is used for filtering an incident terahertz wave, the frequency selection unit has a wire in a spiral line shape, and the wire is used for generating resonance with the incident terahertzwave. In the frequency selective surface-based polarization-adjustable terahertz filter, the frequency selection unit has an asymmetric structure due to the wire being in the spiral line shape, so that the characteristic parameters in different polarization directions are different, the central frequency of the filter can deflect, and the problem that the central frequency of an existing symmetric frequency selective filter cannot be adjusted according to a polarization direction of the incident electromagnetic wave is solved; and moreover, the frequency selective surface-based polarization-adjustable terahertz filter has the advantages of high central frequency transmittance, low loss, high selectivity, low cost and the like, and is convenient to fabricate and process, and the central frequency can be adjusted.

Description

technical field [0001] The invention belongs to the technical field of terahertz filters, in particular to a polarization-tunable terahertz filter based on a frequency selective surface. Background technique [0002] At present, the field of terahertz has increasingly become a hot research direction for researchers from all over the world, and a research boom on this electromagnetic frequency band has also been set off in China. It is generally believed that terahertz is an electromagnetic wave between 0.1THz and 10THz, which is a transition region between electronics and optics, and has important academic and applied research values. As early as the 1970s, terahertz waves attracted the attention of scientists. However, compared with microwaves and light waves, the generation methods and detection methods of this wave band are still very backward. Very limited, and basically still at the theoretical level, forming the so-called "terahertz gap" (Terahertz Gap). In recent ye...

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Problems solved by technology

[0005] In view of the inconvenient adjustment of the resonant frequency of the existing terahertz filter mentioned above, the purpose of the present invention is to provide a polarization-tunable terahertz filter based on a frequency selective surface. Compared with the existing frequency selective surface filter, Its biggest feature is that it can be tuned very simply by rotating the filter or adjusting the polarization direction of the terahertz wave

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