scholarly journals A Tunable Optical Bragg Grating Filter Based on the Droplet Sagging Effect on a Superhydrophobic Nanopillar Array

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3324
Author(s):  
Meng Zhang ◽  
Jiansheng Liu ◽  
Weifeng Cheng ◽  
Jiangtao Cheng ◽  
Zheng Zheng
Keyword(s):  
Refractive Index ◽  
Planar Waveguide ◽  
Tuning Range ◽  
Liquid Droplet ◽  
Tunable Filter ◽  
Bragg Grating ◽  
Refractive Index Sensor ◽  
Narrow Bandwidth ◽  
Simulation Results ◽  
Index Unit

Nanostructures have been widely applied on superhydrophobic surfaces for controlling the wetting states of liquid microdroplets. Many modern optic devices including sensors are also integrated with micro- or nanostructures for function enhancement. However, it is rarely reported that both microfluidics and optics are compatibly integrated in the same nanostructures. In this paper, a novel microfluidic-controlled tunable filter composed of an array of periodic micro/nanopillars on top of a planar waveguide is proposed and numerically simulated, in which the periodic pillars endow both the Bragg grating and the superhydrophobic functions. The tunability of grating is achieved by controlling the sagging depth of a liquid droplet into the periodic pillars. Simulation results show that a narrow bandwidth of 0.4 nm and a wide wavelength tuning range over 25 nm can be achieved by such a microfluidic-based tunable optofluidic waveguide Bragg grating filter. Moreover, this proposed scheme can be easily modified as a refractive index sensor with a sensitivity of 103 nm per refractive index unit.

scholarly journals Temperature Self-Compensated Refractive Index Sensor Based on Fiber Bragg Grating and the Ellipsoid Structure

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5211 ◽  
Author(s):  
Binbin Yan ◽  
Lei Sun ◽  
Yanhua Luo ◽  
Liwei Yang ◽  
Haifeng Qi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Bragg Grating ◽  
Resonant Peak ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Refractive Index Sensor ◽  
Average Sensitivity ◽  
Surrounding Refractive Index ◽  
Index Unit ◽  
Sensing Performance

In this paper, a temperature self-compensated refractive index sensor based on fiber Bragg grating (FBG) and the ellipsoid structure is demonstrated. The ellipsoid can excite the cladding modes and recouple them into the fiber core. Two well-defined wavelength bands are observed in the reflection spectrum of the proposed sensor, i.e., the Bragg resonant peak and the cladding resonant peaks. By measuring the wavelength shift of the cladding resonant peak, the surrounding refractive index (SRI) can be determined, and the wavelength shift of the Bragg resonant peak can be used as a reliable reference to self-compensate the temperature variation (temperature sensitivity of 10.76 pm/°C). When the SRI changes from 1.3352 to 1.3722, the cladding resonant peak redshifts linearly with an average sensitivity of 352.6 pm/RIU (refractive index unit). When the SRI changes from 1.3722 to 1.4426, an exponential redshift is observed with a maximum sensitivity of 4182.2 pm/RIU. Especially, the sensing performance is not very reliant on the distance between the FBG and the ellipsoid, greatly improving the ease of the fabrication.

scholarly journals Etched Fiber Bragg Grating Biosensor Functionalized with Aptamers for Detection of Thrombin

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4298 ◽  
Author(s):  
Aliya Bekmurzayeva ◽  
Kanat Dukenbayev ◽  
Madina Shaimerdenova ◽  
Ildar Bekniyazov ◽  
Takhmina Ayupova ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Bragg Grating ◽  
Chemical Vapor ◽  
Bragg Grating ◽  
Clinical Settings ◽  
Long Period Grating ◽  
Bragg Wavelength ◽  
Sensing System ◽  
Index Unit

A biosensor based on an etched Fiber Bragg Grating (EFBG) for thrombin detection is reported. The sensing system is based on a Fiber Bragg Grating (FBG) with a Bragg wavelength of 1550 nm, wet-etched in hydrofluoric acid (HF) for ~27 min, to achieve sensitivity to a refractive index (RI) of 17.4 nm/RIU (refractive index unit). Subsequently, in order to perform a selective detection of thrombin, the EFBG has been functionalized with silane-coupling agent 3-(aminopropyl)triethoxysilane (APTES) and a cross-linker, glutaraldehyde, for the immobilization of thrombin-binding aptamer. The biosensor has been validated for thrombin detection in concentrations ranging from 10 nM to 80 nM. The proposed sensor presents advantages with respect to other sensor configurations, based on plasmonic resonant tilted FBG or Long Period Grating (LPG), for thrombin detection. Firstly, fabricating an EFBG only requires chemical etching. Moreover, the functionalization method used in this study (silanization) allows the avoidance of complicated and expensive fabrications, such as thin film sputtering or chemical vapor deposition. Due to their characteristics, EFBG sensors are easier to multiplex and can be used in vivo. This opens new possibilities for the detection of thrombin in clinical settings.

Optical characterization of refractive index sensors based on planar waveguide Fabry-Perot Bragg grating cavity

2013 ◽  
Author(s):  
Sang-Mae Lee ◽  
Wan-Taek Jeong ◽  
Kyung-Chun Kim ◽  
Kyung-Jo Kim ◽  
Mincheol Oh ◽  
...  
Keyword(s):  
Refractive Index ◽  
Planar Waveguide ◽  
Optical Characterization ◽  
Bragg Grating ◽  
Fabry Perot ◽  
Refractive Index Sensors

scholarly journals Refractive Index Sensor Based on Double Side-Polished U-Shaped Plastic Optical Fiber

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5253
Author(s):  
Shumin Wang ◽  
Daming Zhang ◽  
Yan Xu ◽  
Siwen Sun ◽  
Xiaoqiang Sun
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Evanescent Wave ◽  
Low Cost ◽  
Temperature Characteristic ◽  
Processing Parameters ◽  
Refractive Index Sensor ◽  
Plastic Optical Fiber ◽  
Favorable Temperature ◽  
Index Unit

A U-shaped double-side polished plastic optical fiber (POF) is demonstrated as a liquid refractive index (RI) sensor. The refractive index of glycerinum solutions is identified by the intensity detection on the bending and evanescent wave loss change. Heat treatment and mechanical polishing are adopted to form the symmetrical side-polished POF probe. The processing parameters are experimentally optimized on the power transmittance. The sensitivity of 1541%/RIU (Refractive Index Unit) can be obtained with a resolution of 5.35 × 10−4 in the scope of 1.33–1.39. The favorable temperature characteristic is proved to offer stable RI sensing from 20 to 50 °C. This simple POF sensor has potentials in low-cost visible light intensity RI detection.

Sign in / Sign up

Export Citation Format

Share Document