scholarly journals Dual-Core Fiber-Based Interferometer for Detection of Gas Refractive Index

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 111
Author(s):  
Haijin Chen ◽  
Xuehao Hu ◽  
Meifan He ◽  
Qianqing Yu ◽  
Zhenggang Lian ◽  
...  
Keyword(s):  
Refractive Index ◽  
Low Cost ◽  
High Sensitivity ◽  
Narrow Slit ◽  
Hollow Core ◽  
Fiber Sensors ◽  
Air Core ◽  
Flow Through ◽  
Core Fiber ◽  
Dual Core

We demonstrate a dual-core fiber-based Mach–Zehnder interferometer that could be used for precise detection of variations in refractive indices of gaseous samples. The fiber used here have a solid germanium-doped silica core and an air core that allows gases to flow through. Coherent laser beams are coupled to the two cores, respectively, and thus excite guiding modes thereby. Interferogram would be produced as the light transmitted from the dual cores interferes. Variations in refractive index of the hollow core lead to variations in phase difference between the modes in the two cores, thus shifting the interference fringes. The fringe shifts can be then interrogated by a photodiode together with a narrow slit in front. The resolution of the sensor was found to be ~1 × 10−8 RIU, that is comparable to the highest resolution obtained by other fiber sensors reported in previous literatures. Other advantages of our sensor include very low cost, high sensitivity, straightforward sensing mechanism, and ease of fabrication.

An Intensity Demodulated Refractive Index Sensor Based on A Hollow-Core Anti-Resonant Fiber

2022 ◽  
Author(s):  
Shidi Liu ◽  
Tianyu Yang ◽  
Liang Zhang ◽  
Ming Tian ◽  
Yuming Dong
Keyword(s):  
Refractive Index ◽  
Structural Parameters ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Hollow Core ◽  
Promising Candidate ◽  
Mid Infrared ◽  
Flow Through ◽  
Demodulation Method ◽  
High Absorption

Abstract A robust and simple mid-infrared hollow-core anti-resonant fiber (ARF) based refractive index (RI) sensor with an intensity demodulation method is presented and analyzed for monitoring liquid analytes. The ARF allows liquid analytes to flow through its hollow area for detection. To obtain ideal sensing performance, an epsilon negative (ENG) material is introduced into the selected anti-resonant tube. With the high absorption of the ENG material, only one fundamental mode is available for detection and is sensitive to the RI variation of analytes. Moreover, the effects of structural parameters on the sensing performances are discussed and analyzed to further understand the mechanism and optimization. The final result shows that the ARF sensor can exhibit a high sensitivity of -372.58 dB/RIU at a fixed wavelength within a broad RI range from 1.33 to 1.45, which covers most liquid analytes. It is a promising candidate for chemical and environmental analysis. Additionally, it has the potential for deep research to feed diverse applications.

scholarly journals A Review of Antiresonant Hollow-Core Fiber-Assisted Spectroscopy of Gases

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5640
Author(s):  
Piotr Jaworski
Keyword(s):  
High Sensitivity ◽  
Gas Absorption ◽  
Hollow Core ◽  
Low Loss ◽  
Promising Alternative ◽  
Long Term Stability ◽  
Air Core ◽  
Core Fiber ◽  
Significant Attention

Antiresonant Hollow-Core Fibers (ARHCFs), thanks to the excellent capability of guiding light in an air core with low loss over a very broad spectral range, have attracted significant attention of researchers worldwide who especially focus their work on laser-based spectroscopy of gaseous substances. It was shown that the ARHCFs can be used as low-volume, non-complex, and versatile gas absorption cells forming the sensing path length in the sensor, thus serving as a promising alternative to commonly used bulk optics-based configurations. The ARHCF-aided sensors proved to deliver high sensitivity and long-term stability, which justifies their suitability for this particular application. In this review, the recent progress in laser-based gas sensors aided with ARHCFs combined with various laser-based spectroscopy techniques is discussed and summarized.

High sensitivity fiber refractive index sensor using tapered 4-core fiber

2021 ◽  
Author(s):  
Zhen Tian ◽  
Lina Suo ◽  
Nan-Kuang Chen ◽  
Yicun Yao ◽  
Liqiang Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Core Fiber

scholarly journals Low-loss ARROW waveguide with rectangular hollow core and rectangular low-density polyethylene/air reflectors for terahertz waves

2018 ◽  
Vol 27 (03) ◽  
pp. 1850029 ◽  
Author(s):  
Henri P. Uranus ◽  
B. M. A. Rahman
Keyword(s):  
Refractive Index ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Hollow Core ◽  
Terahertz Waves ◽  
Low Loss ◽  
Leakage Loss ◽  
Crystal Fiber ◽  
Air Core ◽  
The Waves

Designing low-loss waveguides for terahertz waves is challenging as most materials are very lossy in this frequency band. Most scientists simply consider transmitting the waves through low-loss air, which however also has its own difficulties as index-guiding is not possible. In this paper, we report on the design of low-loss waveguides for terahertz waves and associated results by using a finite element leaky mode solver. These results show that waveguides designed using ARROW (anti-resonant reflecting optical waveguide) approach yield a low combined absorption and leakage loss down to only 0.05[Formula: see text]dB/cm for the q-TE[Formula: see text] fundamental mode using realistic values of refractive index at 1 THz operating frequency. The structure employs rectangular hollow-core and low-density polyethylene/air anti-resonant reflecting bilayers, which can be easily fabricated. These results are compared with those of other structures, i.e., a photonic crystal fiber-like structures using the same materials with rectangular holes, which is shown to give a higher loss of 3[Formula: see text]dB/cm and a suspended air-core waveguide with TOPAS vein offering a loss of 1[Formula: see text]dB/cm.

scholarly journals Multispectral sensing of biological liquids with hollow-core microstructured optical fibres

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Timur Ermatov ◽  
Roman E. Noskov ◽  
Andrey A. Machnev ◽  
Ivan Gnusov ◽  
Vsevolod Аtkin ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Hollow Core ◽  
Optical Resonance ◽  
Optical Biosensing ◽  
Common Strategy ◽  
Biological Liquids ◽  
Spectral Ranges ◽  
Multispectral Sensing ◽  
Microstructured Optical Fibres

Abstract The state of the art in optical biosensing is focused on reaching high sensitivity at a single wavelength by using any type of optical resonance. This common strategy, however, disregards the promising possibility of simultaneous measurements of a bioanalyte’s refractive index over a broadband spectral domain. Here, we address this issue by introducing the approach of in-fibre multispectral optical sensing (IMOS). The operating principle relies on detecting changes in the transmission of a hollow-core microstructured optical fibre when a bioanalyte is streamed through it via liquid cells. IMOS offers a unique opportunity to measure the refractive index at 42 wavelengths, with a sensitivity up to ~3000 nm per refractive index unit (RIU) and a figure of merit reaching 99 RIU−1 in the visible and near-infra-red spectral ranges. We apply this technique to determine the concentration and refractive index dispersion for bovine serum albumin and show that the accuracy meets clinical needs.

scholarly journals Metal Nanowire Assisted Hollow Core Fiber Sensor for an Efficient Detection of Small Refractive Index Change of Measurand Liquid

Plasmonics ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
A. K. Pathak ◽  
S. Ghosh ◽  
R. K. Gangwar ◽  
B. M. A. Rahman ◽  
V. K. Singh
Keyword(s):  
Refractive Index ◽  
Refractive Index Change ◽  
Fiber Sensor ◽  
Hollow Core ◽  
Index Change ◽  
Efficient Detection ◽  
Core Fiber ◽  
Metal Nanowire
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