Visible Measurement of Terahertz Power Based on Capsulized Cholesteric Liquid Crystal Film

We demonstrate a new method to detect terahertz (THz) power using a temperature-supersensitive capsulized cholesteric liquid crystal film based on the thermochromic and thermodiffusion effect, which is clearly observed. A quantitative visualization of the THz intensity up to 4.0 × 103 mW/cm2 is presented. The diameter of the color change area is linearly dependent on the THz radiation power above 0.07 mW in the steady state. Moreover, the THz power can be detected for 1 sec of radiation with a parabolic relation to the color change area. The THz power meter is robust, cost-effective, portable, and even flexible, and can be used in applications such as THz imaging, biological sensing, and inspection.

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Mechanoresponsive Color Change in Cholesteric Liquid Crystal Film

Journal of Photopolymer Science and Technology ◽

10.2494/photopolymer.27.719 ◽

2014 ◽

Vol 27 (6) ◽

pp. 719-721 ◽

Cited By ~ 1

Author(s):

Naho Tanaka ◽

Yasumasa Fukushima

Keyword(s):

Liquid Crystal ◽

Color Change ◽

Cholesteric Liquid Crystal ◽

Crystal Film

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All-fiber-optic VOC gas sensor based on side-polished fiber wavelength selectively coupled with cholesteric liquid crystal film

Sensors and Actuators B Chemical ◽

10.1016/j.snb.2018.06.105 ◽

2018 ◽

Vol 273 ◽

pp. 1816-1826 ◽

Cited By ~ 18

Author(s):

Jieyuan Tang ◽

Junbin Fang ◽

Yinling Liang ◽

Biao Zhang ◽

Yunhan Luo ◽

...

Keyword(s):

Liquid Crystal ◽

Gas Sensor ◽

Fiber Optic ◽

Cholesteric Liquid Crystal ◽

Crystal Film ◽

Side Polished Fiber

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Dye-doped cholesteric liquid crystal light shutter with a polymer-dispersed liquid crystal film

Dyes and Pigments ◽

10.1016/j.dyepig.2016.06.045 ◽

2016 ◽

Vol 134 ◽

pp. 36-40 ◽

Cited By ~ 51

Author(s):

Seung-Won Oh ◽

Jong-Min Baek ◽

Joon Heo ◽

Tae-Hoon Yoon

Keyword(s):

Liquid Crystal ◽

Cholesteric Liquid Crystal ◽

Polymer Dispersed Liquid Crystal ◽

Crystal Film ◽

Polymer Dispersed

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Optical fiber sensor based on a cholesteric liquid crystal film for mixed VOC sensing

Optics Express ◽

10.1364/oe.405627 ◽

2020 ◽

Vol 28 (21) ◽

pp. 31872 ◽

Cited By ~ 1

Author(s):

Yunhe Yang ◽

Dong Zhou ◽

Xiujuan Liu ◽

Yongjun Liu ◽

Shuangqiang Liu ◽

...

Keyword(s):

Liquid Crystal ◽

Optical Fiber ◽

Cholesteric Liquid Crystal ◽

Optical Fiber Sensor ◽

Fiber Sensor ◽

Crystal Film

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Silicon Lens Optimization to Create Diffuse, Uniform Illumination from Incoherent THz Source Arrays

Journal of Infrared Millimeter and Terahertz Waves ◽

10.1007/s10762-021-00828-0 ◽

2021 ◽

Author(s):

Robin Zatta ◽

Daniel Headland ◽

Eamal Ashna ◽

Ritesh Jain ◽

Philipp Hillger ◽

...

Keyword(s):

Integrated Circuit ◽

Radiation Power ◽

Thz Radiation ◽

Far Field ◽

Uniform Illumination ◽

Silicon Lens ◽

Thz Sources ◽

Source Array ◽

Illumination Source ◽

Thz Power

AbstractArrays of terahertz (THz) sources provide a pathway to overcoming the radiation power limitations of single sources. Several independent sources of THz radiation may be implemented in a single integrated circuit, thereby realizing a monolithic THz source array of high output power. Integrated THz sources must generally be backside-coupled to extended hemispherical dielectric lenses in order to suppress substrate modes and extract THz power. However, this lens also increases antenna gain and thereby produces several non-overlapping beams. This is because individual source pixels are relatively large. Hence, their spatial separation on-chip translates to angular separation in the far-field. In other words, there are gaps in their field of view into which very little THz power is projected. Therefore, they cannot homogeneously illuminate an imaging target. This article presents a simple, practical, and scalable method to convert arrays of incoherent THz sources into a diffuse, uniform illumination source without the need for reducing pixel size. Briefly, individual beam divergence is optimized by tailoring the dimensions of the extended hemispherical dielectric lens such that the far-field beams of adjacent source pixels overlap and combine to form a uniform far-field beam. We applied this method to an incoherent 8 × 8-pixel THz source array radiating 10.3 dBm at 0.42 THz as a proof of concept and thereby realized a 10.3-dBm 0.42-THz diffuse, uniform illumination source that was then deployed in a demonstration of THz active imaging.

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