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Graphene-based electronically controlled terahertz anti-reflection film and preparation method thereof

An anti-reflection film and graphene technology, applied in the field of terahertz band devices, can solve the problems of too large difference in thickness of the anti-reflection film, narrow working frequency band, poor stability, etc., to ensure the service life and application range, and high chemical stability. , the effect of expanding the scope of application

Active Publication Date: 2016-04-20
NORTHWEST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This has two disadvantages. First, because the wavelength of this band is much longer than that of the visible band, the required thickness of the anti-reflection film is too thick, which is not conducive to the preparation and application of the film.
Second, in the terahertz band, we often need wide-band terahertz signals (for example, the pulse of the terahertz time-domain spectroscopy system is wide-band, and can usually cover from a few tenths of a terahertz to several terahertz), but the corresponding The thickness of the anti-reflection film required for different bands is too different, so this film cannot achieve wide-band anti-reflection
It can be seen that the current effective anti-reflection coatings in the terahertz band are still lacking, and the existing methods and materials are faced with defects such as narrow working frequency bands, poor stability, and non-tunability to varying degrees.

Method used

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  • Graphene-based electronically controlled terahertz anti-reflection film and preparation method thereof
  • Graphene-based electronically controlled terahertz anti-reflection film and preparation method thereof
  • Graphene-based electronically controlled terahertz anti-reflection film and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] figure 1 Shown is a schematic diagram of the basic structure of an electronically controlled anti-reflection film composed of two graphene layers, which is a schematic view of the structure viewed from the side. The device has a three-layer structure, including two layers of graphene layers 1 and 3, and a dielectric layer 2 that completely separates adjacent graphene layers. The electrode 4 is connected between the graphene layer 1 and the graphene layer 3 and applied with a voltage 5. for adjustment.

Embodiment 2

[0079] figure 2 Shown is a schematic diagram of the basic structure of an electrically controlled anti-reflection film composed of four graphene layers, which is a schematic diagram of the structure viewed from the side. The anti-reflection film has a 7-layer structure, including 7 layers of graphene, and a dielectric layer 2 that completely separates adjacent graphenes. Viewed from top to bottom in the figure, the first and third graphene layers are respectively connected to one electrode, and the second and fourth graphene layers are respectively connected to the other electrode. The voltage on these two electrodes is 5, odd-numbered layers It has the same potential as the even-numbered graphene layers, and a voltage of 5 can be applied to adjust the conductivity of each graphene layer. exist figure 2 In , the electrodes are not shown. In practical applications, the connection between conductive wires and graphene should be realized by making electrodes.

[0080] In act...

Embodiment 3

[0082] In this example, we selected the following devices to prepare terahertz anti-reflection coatings with different numbers of graphene layers:

[0083] Graphene sample (fixed) parameters: area 1cm 2 , carrier scattering probability 100cm -1 , Fermi velocity v F =1.1×10 6 m / s, test temperature: 300K, preparation method: CVD.

[0084] (non-fixed) parameters of graphene: number of layers: 2, 4, 6 voltage: 0 ~ 80V.

[0085] Dielectric layer: SiO 2 , thickness: 50nm; method: magnetron sputtering, refractive index: 1.5.

[0086] Electrodes: copper, magnetron sputtering.

[0087] The frequency of the incident terahertz wave is 1 THz. The Fermi energy level of graphene is 0eV and -0.315eV, and the corresponding voltage is adjusted from 0V to 80V, which is the upper and lower limits of the change of the Fermi energy level of graphene.

[0088] The substrate used to verify the anti-reflection performance is high-resistance silicon with a thickness of 500 μm and a refractive ...

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Abstract

The invention discloses an electrically controlled terahertz anti-reflection film based on a graphene material, a preparation method and a use method. The anti-reflection film has a multi-layer structure, including at least two layers of graphene, and a layer that completely separates adjacent graphenes. The dielectric layer, the first layer of graphene and the second layer of graphene are connected with electrodes and applied with a voltage for electric field adjustment, and can be processed or attached to a substrate or a terahertz element during use. The present invention utilizes the anti-reflection film prepared by the multi-layer film structure to change the refractive index range of the terahertz element or the substrate that realizes the anti-reflection performance through different layers of graphene, and theoretically realizes the anti-reflection of any refractive index material. Through voltage regulation, the anti-reflection performance can be adjusted with higher precision.

Description

technical field [0001] The invention belongs to the technical field of terahertz band devices, in particular to a graphene-based terahertz wave antireflection film and a preparation method thereof. Background technique [0002] Terahertz (THz for short) is the frequency unit of electromagnetic waves, and 1 terahertz is equal to 1012 Hz. Terahertz waves refer to electromagnetic waves ranging from 0.3THz to 10THz, corresponding to wavelengths ranging from 0.03mm to 1mm. The terahertz band has higher spatial resolution (high frequency) and time resolution (picosecond pulse), less energy will not destroy matter, and it is the resonance frequency band of vibration and rotation of biological macromolecules. These characteristics make it have potential application prospects in fields such as broadband communication, radar, electronic countermeasures, electromagnetic weapons, astronomy, non-destructive testing, medical imaging, and security inspection. Before the 1980s, limited by...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B5/08G02B1/115
Inventor 徐新龙周译玄任兆玉白晋涛
Owner NORTHWEST UNIV