Visual terahertz power meter based on cholesteric liquid crystal and testing method thereof

The technology of a cholesteric liquid crystal and a testing method is applied in the field of visual terahertz power meter and its testing, which can solve the problems of low practical performance, and achieve the effects of stable device performance, easy expansion and operation, and simple preparation method.

Active Publication Date: 2019-04-16
NANJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Woolard et al. reported a CLC imager for THz quantum cascade lasers, bu

Method used

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  • Visual terahertz power meter based on cholesteric liquid crystal and testing method thereof
  • Visual terahertz power meter based on cholesteric liquid crystal and testing method thereof
  • Visual terahertz power meter based on cholesteric liquid crystal and testing method thereof

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Experimental program
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Embodiment 1

[0045] This embodiment shows the relationship between THz power magnitude and response time and the color change diameter of CCLCF in thermal equilibrium state. Such as Figure 6 A direct visualization at different THz powers is shown, and the images show a clear temperature increase and thermal diffusion with an increase in the diameter of the color change due to the increase in THz intensity. To facilitate image analysis, the CCLCF images based on hue were processed using ImageJ software. Figure 7 Indicates that the diameter of the color change increases with the increase of terahertz power in the state of thermal equilibrium, Figure 7 The relationship between the diameter of the color change and the THz power in the steady state is given. Figure 7 The ordinate of represents the diameter of the color change region, and the abscissa represents the THz power. The detectable THz field threshold is about 0.07mW, at which point a color change visible to the naked eye can be...

Embodiment 2

[0047] This embodiment shows the relationship between the THz power and the transient color change area when the THz radiation is irradiated for 1 second in the transient state. The specific structural design is attached figure 1 Shown, preparation mode is identical with embodiment 1. Transient detection enables rapid acquisition of THz power by measuring at a point in time prior to thermal equilibrium. Change the THz power by rotating the wire grid, and detect the color change of the area. When the wire grid polarizer θ = 0° (parallel to the polarization of the THz wave), there is no THz transmission. Then, changing the polarizer angle to 40°, 60°, and 80°, radiometric images were obtained from the insets taken with a smartphone. Figure 9 The ordinate of represents the THz power, and the abscissa represents the area of ​​the color change region. Figure 9 is the relationship between THz power and the area of ​​transient color change when terahertz is irradiated for 1 sec...

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Abstract

The invention discloses a visual terahertz power meter based on cholesteric liquid crystal and a testing method thereof. The visual terahertz power meter comprises a capsule-type cholesteric liquid crystal thin film which generates a visual color region change along with changes of THz, wherein the capsule-type cholesteric liquid crystal thin film comprises a three-layer structure, and the structure sequentially comprises an acrylic resin film, cholesteric liquid crystals and carbon blacks from top to bottom. According to the meter and the testing method, simplicity, convenience and high efficiency are achieved, the meter and the testing method are particularly capable of detecting the power of strong THz waves, the increase of the size of the color change region caused by THz absorption is quantified by utilizing the thermochromatic effect and the thermal diffusion effect of the cholesteric liquid crystals, the meter is not limited by color change saturation, is stable and practical,and does not need any additional components for measuring temperature.

Description

technical field [0001] The invention relates to a visual terahertz power meter based on cholesteric liquid crystal and a testing method thereof, which can be used in the technical field. Background technique [0002] Terahertz (THz) waves are waves with a frequency of 0.1-10THz (1THz=10 12 Hz, the corresponding wavelength is electromagnetic waves between 3000-30μm). Due to the unique advantages of THz waves: low photon energy, it is suitable for biopsy of biological tissues; the vibration and rotation energy levels of the skeleton of many condensed matter and biological macromolecules, and the weak interactions between many molecules (hydrogen bonds, etc.) It is in the THz frequency band; many non-metallic and non-polar materials have little absorption of THz waves and have high permeability; compared with visible light and infrared rays, THz waves have extremely high directionality and strong cloud penetration ability. It can achieve a wireless transmission rate of more t...

Claims

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Application Information

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IPC IPC(8): G01J1/50
CPCG01J1/50
Inventor 王磊肖芮文姜浩研
Owner NANJING UNIV OF POSTS & TELECOMM
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