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Development and analysis of Photonic Crystal Fiber Mach-Zehnder interferometer for highly sensitive detection and quantification of gasesNazeri, Kaveh 13 October 2020 (has links)
Gas sensing is essential for safety and maintenance operations in many industries, including power generation, petrochemical, capture and storage technologies, and the food-processing sector. The properties of fiber-optic sensors make them a superior choice for environmental monitoring applications, especially in extreme conditions, and particularly when compared against conventional electro-optical sensors. Their advantageous properties include immunity to electromagnetic radiation, high temperature durability, high sensitivity and the ability for high resolution detection, as well as multifunctional sensing capabilities such as temperature, humidity, pressure, strain, and corrosion. Among different types of interferometers, Mach-Zehnder Interferometers (MZI) have received significant attention because they are robust, compact, and have high levels of precision.
In this dissertation, we present an in-line and compact MZI point sensor designed for sensing refractive index. In comparison with various types of interferometers, fiber MZI based RI sensing was selected based on its enhanced sensitivity and fabrication simplicity. The MZI sensor is developed using photonic crystal fiber and demonstrated for high sensitivity detection and measurement of pure gases. The transmission spectrum of MZI sensors is formed by interference between the cladding and core modes. To construct the device, the sensing element fiber was placed and aligned between two single-mode fibers with air gaps at each side. Two linear-translation micro stages were used to accurately differ and adjust gap lengths from 0 to 5mm. Great measurement repeatability was shown in the cyclic test for the detection of various gases such as methane and helium. A high RI measurement resolution of 2.1 E-7 and a sensitivity of 4629 nm/RIU was achieved, which is among the highest reported. Results show that the sensitivity of the fabricated MZI increases from 3000 nm/RIU to 4600 nm/RIU when the length of the sensing element fiber decreases from 5 mm to 3.3 mm. Furthermore, the device was packaged to demonstrate the laboratory-scale monitoring, as well as leakage detection of different concentrations of CO2 in both subsurface soil and aqueous environments. Two water resistant but gas permeable membranes were used to package the sensor, to achieve a good balance of CO2 permeability and water resistance. The experimental study of this work reveals the great potential of the fiber-optic approach for environmental monitoring of CO2.
This study also explores other potential applications. Three types of sensors were fabricated using the proposed configuration employing 4 mm stub of (i) solid core Photonic Crystal Fiber (PCF), (ii) 10 µm Hollow core PCF (HC-PCF), and (iii) 20 µm HC-PCF as the sensing elements. We compared the performance of these sensors for detecting and measuring the quantity of gas present. As the transmission signals correspond to the frequency components in the sensor’s Fast Fourier Transform (FFT) spectrum, the effect of gap distance on the number and amplitude distribution of the modes was examined in an effort to optimize the design elements. The MZI sensors are highly sensitive to low percentages of CH4 and CO2, making them suitable for greenhouse gas measurement. / Graduate
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Development of a Miniature, Semi-Distributed Sapphire Fiber Optic Thermometer for Harsh and High Temperature EnvironmentsDePew, Keith Alan 22 January 2013 (has links)
Fiber optic temperature sensing has become a well-defined field in the past few decades [1] through the use of Fiber Bragg Gratings, Fabry-Perot interferometry, and pyrometry, to list several techniques in use today. The use of fiber optics offers significant advantages over electronic sensing in terms of size and insensitivity to harsh conditions such as extreme temperatures and corrosive environments. The availability of optical sapphire materials, including fibers, has allowed the creation of fiber optic sensing elements able to continuously operate at temperatures of 1600"C [2] or more, thus outstripping the abilities of many commonly used thermocouples (excluding platinum types R, S, and B) [3] which will also exhibit a sensitivity to electromagnetic fields.
In addition to the aforementioned benefits, fiber optic sensing techniques provide a great deal of accuracy in temperature measurement over the entire working range of the sensor.
The work documented in this thesis consists of efforts to minimize the overall footprint of a sapphire based extrinsic Fabry-Perot interferometry (EFPI) temperature sensing element, as well as strides made in multiplexing the same element and reducing the error potential from cross sensitivity of the thermometer with applied strain. This work has been variously funded by Pratt & Whitney and the Department of Energy. / Master of Science
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Studies on Dielectric Constants of Liquids at Microwave Frequencies by a Novel Coaxial Cable Fabry-Perot Interferometer SensorZeng, Shixuan January 2018 (has links)
No description available.
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Quantum Nonlinear OpticsGao, Xuesong 06 September 2019 (has links)
No description available.
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Development of the point-diffraction interferometer wavefront sensor for extreme adaptive optics / 極限補償光学のための点回折干渉計型波面センサの開発Tsukui, Ryo 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24416号 / 理博第4915号 / 新制||理||1702(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 栗田 光樹夫, 准教授 岩室 史英, 教授 太田 耕司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
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Investigating sub-10 nm-thick Cloaking Films on Sessile Water Droplets Placed on Slippery Lubricant-Infused Porous Surfaces (SLIPS)Ridwan, Muhammad Ghifari 04 1900 (has links)
Slippery liquid-infused porous surfaces (SLIPS) – a new class of bio-inspired liquid-repellent surfaces – comprise arbitrarily porous architectures filled with oils that exhibit high interfacial tensions to probe liquids and present ultralow contact angle hysteresis (<〖10〗^°). However, before practical technologies based on SLIPS can be designed at large-scale, a number of fundamental questions remain to be answered. For instance, depending on the sign of the spreading coefficient of the Vapor(V)-lubricant oil(O)-liquid(L) system, defined as S_(OL(V))=γ_LV-γ_LO-γ_OV>0, the lubricating layer forms a layer at the liquid-vapor interface (here, γ_LV is a liquid-vapor interfacial tension, γ_LO – liquid-oil, and γ_OV – oil-vapor). This “cloaking” of liquid drops can deplete SLIPS’ lubricant over time and contaminate the probed liquid. So far, cloaking has been investigated by contact angle goniometry and confocal microscopy, which cannot resolve films of molecular thickness and factors that govern the equilibrium thickness of those films are not entirely clear. Here, we report on the development and application of a reflective-mode SFA platform to characterize the cloaking of water droplets placed on SLIPS. A multilayer matrix method is utilized to analyze the interferometry data. Using this complementary experimental and analytical approach, we determined the thickness of the cloaking layer for the FDTS(solid)-VF-40(lubricant)-water(probe liquid)-air system to be z3= 7±1 nm. Towards deeper insights into the intermolecular and surface forces responsible for cloaking, we demonstrate that repulsive van der Waals interactions are responsible for stabilizing the cloaking film at the water-air interface. Our experimental platform and the analytical framework should facilitate investigations of other SLIPS and probe liquid systems down to the molecular-scale resolution. These findings might aid the rational design of SLIPS, e.g., for drag reduction, anti-biofouling, and anti-corrosion.
In addition to investigating SLIPS, We addressed the following questions with the help of atomic force microscopy (AFM): (i) how do zwitterionic osmolytes modulate electrostatic and hydrophobic interactions in nanoscale confinement, and (ii) is it possible to have two negatively charged surfaces attract each other? Our findings are presented as appendices in this thesis.
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Development of 320GHz Interferometer System for Electron Density Measurement in Heliotron J / ヘリオトロンJにおける電子密度計測のための320GHz干渉計システムの開発ZHANG, Pengfei 24 November 2023 (has links)
京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24975号 / エネ博第471号 / 新制||エネ||88(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー変換科学専攻 / (主査)教授 長﨑 百伸, 教授 田中 仁, 教授 稲垣 滋 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM
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System Identification of a Cantilever Beam with Interferometer Measurement Using Adaptive FiltersKochavi, Jordan D 01 June 2022 (has links) (PDF)
Laser interferometry, commonly used in high-precision motion control systems, is rarely adopted in experimental vibration analysis because its installation and mounting is invasive to dynamical systems. However, metrology systems that already utilize laser interferometry, such as profilometry in semiconductor manufacturing, may benefit from interferometer feedback for signal processing. This study investigates the use of laser interferometry for system identification through a piezoelectrically actuated cantilevered beam.
The model of the beam including piezo actuators and optical measurement components are established through the Euler-Bernoulli beam theory. From the method of separation of variables, the continuous system is transformed into a discrete system represented in a state-space form. By performing the Laplace transformation of the state-space form, we obtain the analytical transfer function of interferometer displacement versus actuator input, which is then validated numerically and experimentally. Adaptive filters based on FIR and IIR are designed to identify the transfer function. Because of the slow convergence of such filters, a recursive LMS algorithm is designed to accelerate computation. It is experimentally demonstrated that the precision measurement of interferometer can lead to highly accurate results of system identification.
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Studies on Molecular and Ion Transport in Silicalite Membranes andApplications as Ion Separator for Redox Flow BatteryYang, Ruidong 10 October 2014 (has links)
No description available.
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Metal-Ceramic Coaxial Cable Sensors for Distributed Temperature MonitoringTrontz, Adam J. 04 September 2018 (has links)
No description available.
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