scholarly journals Optical Microfiber Sensor : A Review

2021 ◽  
Vol 2075 (1) ◽  
pp. 012021
Author(s):  
Mohd Hafiz Jali ◽  
Hazli Rafis Abdul Rahim ◽  
Md Ashadi Md Johari ◽  
Mohamad Faizal Baharom ◽  
Aminah Ahmad ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Environmental Control ◽  
High Sensitivity ◽  
Low Noise ◽  
Detection Range ◽  
Sensing Applications ◽  
Manufacturing Process Control ◽  
Compact Size ◽  
Temperature Levels ◽  
Optical Microfiber

Abstract Due to numerous benefits such as geometrical simplicity, compact size, high sensitivity, broad detection range, low noise, and high accuracy, optical devices have attracted a lot of interest for sensing applications. It is critical in a variety of sectors, including cultural relic preservation, warehouse products maintenance, manufacturing process control, semiconductor, agriculture, food production storage, environmental control, health industries, chemical and home improvement. It outperforms its electronic equivalent owing to its capacity to function in tough and demanding situations such as combustible surroundings, greater pressure and temperature levels, and the ability to send signals over long distances without electromagnetic interference. Optical fiber sensors are classified based on their operating principles such as interferometers, fiber Bragg gratings (FBG), resonators and whispering galleries modes (WGM). This paper presents a comprehensive review related to the optical microfiber sensor such as its properties, fabrication techniques, evanescent wave, optical micro resonators and recent study on the application of microfiber towards humidity sensing. This review could be beneficial to help other researchers to gain greater view in the field of optical microfiber sensor.

A high-sensitivity strain/inertial seismograph installation

1970 ◽  
Vol 60 (6) ◽  
pp. 1803-1822 ◽  
Author(s):  
James E. Fix ◽  
John R. Sherwin
Keyword(s):  
Environmental Control ◽  
Earth Tide ◽  
High Sensitivity ◽  
Low Noise ◽  
Photographic Film ◽  
Noise Levels ◽  
Directional Response ◽  
Long Period ◽  
Phase Velocities ◽  
Short Period

Abstract A seismograph complex consisting of short-period (SP), long-period (LP), and extended long-period (XLP) inertial and strain seismographs has been installed. Recordings are made on magnetic tape and photographic film. Routine magnifications on the 20-trace, 16-mm film recorders for all three components are: SP inertial, 500 K; LP inertial, 100 K. The noise levels permit equivalent magnifications on the strain seismographs. The complex provides seismic wave discrimination by directional response, which is independent of period, and by detection of differences in phase velocities between P, S, Love, or Rayleigh arrivals. The strain seismographs use 40-m-long rods and moving coil transducers with generator constants of 32,000 v/m/sec. They sense waves of 5 × 10-13 strain at 30 sec and reject the 2 × 10-8 earth-tide strain. A low-noise preamplifier drives a filter assembly which provides SP, LP, and XLP strain outputs. The complex is installed in an abandoned mine 50 km southeast of Phoenix, Arizona. Environmental control is provided by burial at a depth of about 110 m in a quartz diorite, by sealing the mine, and by insulating the seismometers.

scholarly journals Solid State Electronic Sensors for Detection of Carbon Dioxide

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3848 ◽  
Author(s):  
Ami Hannon ◽  
Jing Li
Keyword(s):  
Carbon Dioxide ◽  
Iron Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Multiwall Carbon Nanotubes ◽  
High Sensitivity ◽  
Space Applications ◽  
Detection Range ◽  
Ultra Low Power ◽  
Compact Size

Detection of carbon dioxide (CO2) is very important for environmental, health, safety and space applications. We have studied novel multiwall carbon nanotubes (MWCNTs) and an iron oxide (Fe2O3) nanocomposite based chemiresistive sensor for detection of CO2 at room temperature. The sensor has been miniaturized to a chip size (1 cm × 2 cm). Good sensing performance was observed with a wide detection range of CO2 concentrations (100–6000 ppm). Structural properties of the sensing materials were characterized using Field-Emission Scanning Electron Microscopy, Fourier-Transform Infrared and Raman spectroscopies. The greatly improved sensitivity of the composite materials to CO2 can be attributed to the formation of a depletion layer at the p-n junction in an MWCNT/iron oxide heterostructure, and new CO2 gas molecules adhere to the high surface area of MWCNTs due to the concentration gradient. The test results showed that the CO2 sensor possesses fast response, compact size, ultra-low power consumption, high sensitivity and wide dynamic detection range.

scholarly journals Relative Humidity Sensors Based on Microfiber Knot Resonators—A Review

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5196 ◽  
Author(s):  
Young-Geun Han
Keyword(s):  
Relative Humidity ◽  
High Sensitivity ◽  
Physical Parameters ◽  
Humidity Sensors ◽  
Coating Materials ◽  
High Q ◽  
Sensing Applications ◽  
Compact Size ◽  
The Many ◽  
Humidity Sensitivity

Recent research and development progress of relative humidity sensors using microfiber knot resonators (MKRs) are reviewed by considering the physical parameters of the MKR and coating materials sensitive to improve the relative humidity sensitivity. The fabrication method of the MKR based on silica or polymer is briefly described. The many advantages of the MKR such as strong evanescent field, a high Q-factor, compact size, and high sensitivity can provide a great diversity of sensing applications. The relative humidity sensitivity of the MKR is enhanced by concerning the physical parameters of the MKR, including the waist or knot diameter, sensitive materials, and Vernier effect. Many techniques for depositing the sensitive materials on the MKR surface are discussed. The adsorption effects of water vapor molecules on variations in the resonant wavelength and the transmission output of the MKR are described regarding the materials sensitive to relative humidity. The sensing performance of the MKR-based relative humidity sensors is discussed, including sensitivity, resolution, and response time.

scholarly journals Dissipation Analysis Methods and Q-Enhancement Strategies in Piezoelectric MEMS Laterally Vibrating Resonators: A Review

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4978 ◽  
Author(s):  
Cheng Tu ◽  
Joshua E.-Y. Lee ◽  
Xiao-Sheng Zhang
Keyword(s):  
Integrated Circuit ◽  
High Sensitivity ◽  
Low Noise ◽  
Quality Factors ◽  
Rf Filters ◽  
Resonant Sensors ◽  
Sensing Applications ◽  
Analysis Methods ◽  
Mems Resonators ◽  
Piezoelectric Mems

Over the last two decades, piezoelectric resonant sensors based on micro-electromechanical systems (MEMS) technologies have been extensively studied as such sensors offer several unique benefits, such as small form factor, high sensitivity, low noise performance and fabrication compatibility with mainstream integrated circuit technologies. One key challenge for piezoelectric MEMS resonant sensors is enhancing their quality factors (Qs) to improve the resolution of these resonant sensors. Apart from sensing applications, large values of Qs are also demanded when using piezoelectric MEMS resonators to build high-frequency oscillators and radio frequency (RF) filters due to the fact that high-Q MEMS resonators favor lowering close-to-carrier phase noise in oscillators and sharpening roll-off characteristics in RF filters. Pursuant to boosting Q, it is essential to elucidate the dominant dissipation mechanisms that set the Q of the resonator. Based upon these insights on dissipation, Q-enhancement strategies can then be designed to target and suppress the identified dominant losses. This paper provides a comprehensive review of the substantial progress that has been made during the last two decades for dissipation analysis methods and Q-enhancement strategies of piezoelectric MEMS laterally vibrating resonators.

scholarly journals A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3308 ◽  
Author(s):  
Zhihua Wei ◽  
Jie Huang ◽  
Jing Li ◽  
Junshan Li ◽  
Xuyang Liu ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
High Sensitivity ◽  
Substrate Integrated Waveguide ◽  
Humidity Sensing ◽  
Food Industries ◽  
High Q ◽  
Sensing Applications ◽  
Compact Size ◽  
Highly Sensitive ◽  
Humidity Chamber

In this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size reduction (up to 85.9%) in comparison with a conventional TM010-mode circular SIW cavity. The operating principle of the humidity sensor is based on the resonant method, in other words, it utilizes the resonant properties of the sensor as signatures to detect the humidity condition of the ambient environment. To this end, a mathematical model quantitatively relating the resonant frequency of the sensor and the relative humidity (RH) level was established according to the cavity perturbation theory. The sensing performance of the sensor was experimentally validated in a RH range of 30%–80% by using a humidity chamber. The measured absolute sensitivity of the sensor was calculated to be 135.6 kHz/%RH, and the corresponding normalized sensitivity was 0.00627%/%RH. It was demonstrated that our proposed sensor not only has the merits of compact size and high sensitivity, but also benefits from a high Q-factor and ease of fabrication and integration. These advantages make it an excellent candidate for humidity sensing applications in various fields such as the agricultural, pharmaceutical, and food industries.

scholarly journals State-of-the-Art Optical Devices for Biomedical Sensing Applications—A Review

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 973
Author(s):  
N. L. Kazanskiy ◽  
S. N. Khonina ◽  
M. A. Butt ◽  
A. Kaźmierczak ◽  
R. Piramidowicz
Keyword(s):  
Optical Sensors ◽  
Low Cost ◽  
High Sensitivity ◽  
Sensor Technology ◽  
Biomedical Sensors ◽  
Plasmonic Sensors ◽  
Biomedical Sensing ◽  
Sensing Applications ◽  
Compact Size ◽  
Pros And Cons

Optical sensors for biomedical applications have gained prominence in recent decades due to their compact size, high sensitivity, reliability, portability, and low cost. In this review, we summarized and discussed a few selected techniques and corresponding technological platforms enabling the manufacturing of optical biomedical sensors of different types. We discussed integrated optical biosensors, vertical grating couplers, plasmonic sensors, surface plasmon resonance optical fiber biosensors, and metasurface biosensors, Photonic crystal-based biosensors, thin metal films biosensors, and fiber Bragg grating biosensors as the most representative cases. All of these might enable the identification of symptoms of deadly illnesses in their early stages; thus, potentially saving a patient’s life. The aim of this paper was not to render a definitive judgment in favor of one sensor technology over another. We presented the pros and cons of all the major sensor systems enabling the readers to choose the solution tailored to their needs and demands.

scholarly journals Study on the Nanosensor Based on a MIM Waveguide with a Stub Coupled with a Horizontal B-Type Cavity

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 125
Author(s):  
Shubin Yan ◽  
Haoran Shi ◽  
Xiaoyu Yang ◽  
Jing Guo ◽  
Wenchang Wu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Spectral Characteristics ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Plasmonic Sensors ◽  
Sensing Applications ◽  
Compact Size ◽  
Metal Insulator Metal ◽  
The Difference ◽  
Mim Waveguide

Due to their compact size and high sensitivity, plasmonic sensors have become a hot topic in the sensing field. A nanosensor structure, comprising the metal–insulator–metal (MIM) waveguide with a stub and a horizontal B-Type cavity, is designed as a refractive index sensor. The spectral characteristics of proposed structure are analyzed via the finite element method (FEM). The results show that there is a sharp Fano resonance profile, which is excited by a coupling between the MIM waveguide and the horizontal B-Type cavity. The normalized HZ field is affected by the difference value between the outer radii R1 and R2 of the semi-circle of the horizontal B-Type cavity greatly. The influence of every element of the whole system on sensing properties is discussed in depth. The sensitivity of the proposed structure can obtain 1548 nm/RIU (refractive index unit) with a figure of merit of 59. The proposed structure has potential in nanophotonic sensing applications.

scholarly journals Recent Progress in Microfiber-Optic Sensors

2021 ◽  
Vol 11 (1) ◽  
pp. 45-68
Author(s):  
Wei Luo ◽  
Ye Chen ◽  
Fei Xu
Keyword(s):  
Fiber Optics ◽  
Recent Progress ◽  
Response Times ◽  
Functional Materials ◽  
High Sensitivity ◽  
Fast Response ◽  
Basic Principles ◽  
Area Of Interest ◽  
Compact Size ◽  
Optical Microfiber

AbstractRecently, microfiber-optic sensors with high sensitivity, fast response times, and a compact size have become an area of interest that integrates fiber optics and nanotechnology. Distinct advantages of optical microfiber, such as large accessible evanescent fields and convenient configurability, provide attractive benefits for micro- and nano-scale optical sensing. Here, we review the basic principles of microfiber-optic sensors based on a broad range of microstructures, nanostructures, and functional materials. We also introduce the recent progress and state-of-the-art in this field and discuss the limitations and opportunities for future development.

scholarly journals Optical Fiber Sensor for Heavy Chemical Detection: An Overview

2021 ◽  
Vol 2075 (1) ◽  
pp. 012010
Author(s):  
Nurul Athirah Mohamad Abdul Ghafar ◽  
Arni Munira Markom ◽  
Marni Azira Markom ◽  
Ahmad Razif Muhammad
Keyword(s):  
Optical Fiber ◽  
Electromagnetic Interference ◽  
Low Cost ◽  
Optical Fiber Sensor ◽  
High Sensitivity ◽  
Electrochemical Analysis ◽  
Detection Methods ◽  
Fiber Sensor ◽  
Sensor Technology ◽  
Compact Size

Abstract Heavy metal contaminations such as mercury, lead, arsenic, cadmium, and zinc are becoming more serious and have become a hazard to human health. Due to their non-biodegradable nature, they can easily accumulate in the environment and cause toxicity even at low concentrations. Therefore, detecting the presence of these metal ions requires a highly sensitive sensing method. Traditional detection methods, such as electrochemical analysis, require complicated sample preparation, are costly, and typically require a lengthy measurement period. These days, optical fiber sensors have been acknowledged due to their unique characteristics such as compact size, high sensitivity, low cost, high flexibility, and immunity to electromagnetic interference. An overview of an optical fiber sensor technology for heavy chemical measurement is discussed in this paper. The sensing mechanisms are summarized, as well as the chemical water quality parameters and sensitivities.

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