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Search results for: low coherent interferometer
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The use of low-coherence interferometer for sugar content determination
PublicationIn this article, the implementation of low-coherence interferometer with signal processing in time domain for sugar content determination in aqueous solution is presented. The elaborated measurement set-up was tested with the use of synthesized source made of two low-coherence sources. The use of two sources with dedicated parameters enabled to obtain a proper metrological parameters of the measurement system. The elaborated low-coherence...
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Improved method of signal processing used in low-coherent systems
PublicationW artykule przedstawiono nowe,opracowane metody przetwarzania sygnału w układach niskokoherencyjnych. W układach niskokoherencyjnych z analizą sygnału w dziedzinie czasu zaproponowano wykorzystanie źródeł syntezowanych, natomiast w przypadku układów z przetwarzaniem sygnału w dziedzinie widma zaproponowano metodę opartą na pomiarze przesunięcia widma sygnału pomiarowego. Wyniki przeprowadzonych badań eksperymentalnych zamieszczone...
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The low coherence Fabry-Pérot interferometer with diamond and ZnO layers
PublicationThe authors present a fiber-optic Fabry-Pérot interferometer built with the application of diamond and zinc oxide (ZnO) thin layers. Thin ZnO films were deposited on the tip of a standard telecommunication single-mode optical fiber (SMF- 28) while the diamond layer was grown on the plate of silicon substrate. Investigated ZnO layers were fabricated by atomic layer deposition (ALD) and the diamond films were deposited using Microwave...
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Shaping coherence function of sources used in low-coherent measurement techniques
PublicationW niskokoherencyjnych technikach pomiarowych kształt funkcji koherencji wykorzystywanego źródła ma bezpośredni wpływ na parametry metrologiczne układu pomiarowego. Z tego względu, w wielu aplikacjach niezbędne jest użycie metod pozwalających na zmianę kształtu tej funkcji. W artykule przeanalizowano możliwości kształtowania funkcji koherencji, a przedstawione analizy teoretyczne i wyniki symulacji komputerowych wskazują, że kształtowanie...
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Shaping coherence function of sources used in low-coherent measurement techniques
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Shaping of coherence function of sources used in low-coherent measurement techniques
PublicationW artykule przedstawiono zależność pomiędzy charakterystyką widmową źródła i ekwiwalentną długością drogi koherencji źródła. Wyniki analizy teoretycznej i symulacji komputerowych wykazały, że użycie źródła syntezowanego wpływa na zmniejszenie wartości ekwiwalentnej długości drogi koherencji. Dodatkowo wykazano, że zmniejszenie ekwiwalentnej długości drogi koherencji można otrzymać poprzez odpowiednie kształtowanie funkcji koherencji...
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Theoretical and experimental investigation of low-noise optoelectronic system configurations for low-coherent optical signal detection
PublicationW artykule przedstawiono wyniki teoretycznej i eksperymentalnej analizy konfiguracji niskokoherencyjnego układu detekcji sygnałów optycznych. Zaprezentowano zaprojektowany układ detekcji optycznych sygnałów niskokoherencyjnych, który pozwala na pracę w konfiguracji zrównoważonej i niezrównoważonej, co umożliwia porównanie parametrów obu konfiguracji.
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Enhancement of fiber-optic low-coherence Fabry-Pérot interferometer with ZnO ALD films
PublicationIn this paper investigation of the enhanced fiber-optic low coherence Fabry-Pérot interferometer with zinc oxide (ZnO) film deposited by atomic layer deposition (ALD) was presented. Model of the interferometer, which was constructed of single-mode optical fiber with applied ZnO ALD films, was built. The interferometer was also examined by means of experiment. Measurements were performed for both reflective and transmission modes,...
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Low-Coherence Interferometer with Nanocrystalline Diamond Films with Potential Application to Measure Small Biological Samples
PublicationThe study investigates a case of a low-coherence fiber-optic Fabry–Prerot interferometer with a nanocrystalline diamond (NCD) mirror. The method of achieving double density of interference fringes is proposed by the application of birefringent material in the cavity of the interferometer. It can be used to reduce sample volume in comparison to conventional interferometers. The use of a biocompatible diamond mirror makes it specifically...
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Determination of refractive index dispersion using fiber-optic low-coherence Fabry–Perot interferometer: implementation and validation
PublicationWe present the implementation and validation of low-coherence Fabry–Perot interferometer for refractive index dispersion measurements of liquids. A measurement system has been created with the use of four superluminescent diodes with different optical parameters, a fiber-optic coupler and an optical spectrum analyzer. The Fabry–Perot interferometer cavity has been formed by the fiber-optic end and mirror surfaces mounted on a micromechanical...
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Fiber optic low-coherence Fabry-Pérot interferometer with ZnO layers in transmission and reflective mode: comparative study
PublicationA construction of a low-coherence fiber-optic Fabry-Pérot interferometer using a thin ZnO layer as a reflective surfaces was proposed and examined. In the investigated setup, the ZnO layer of thickness 200 nm were deposited on the face of the standard telecommunication single-mode optical fiber (SMF-28). Measurements of interference signal were performed for the interferometer working in the transmission and reflective mode, as...
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Computer-aided analysis of signals from a low-coherence Fabry-Perot interferometer used for measurements of biological samples
PublicationThe aim of the study was to develop an automated computer-aided system for analysis of spectrograms obtained from measurements of biological samples performed with a low-coherence Fabry-Pérot interferometer. Information necessary to determine dispersion characteristics of measured materials can be calculated from the positions of the maxima and minima that are present in their spectra. The main challenge faced during the development...
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Performance of Coherent Modulation Scheme Used in Acoustic Underwater Communication System
PublicationThe development of an acoustic underwater communication system for shallow waters is still a big scientificand construction challenge. Currently, non-coherent modulations in combination with strong channel coding are used to achieve reliable communication with low rate in such a channel. To obtain transmission with a higher transmission rate, it is required to use coherent modulation. This paper presents the assumptions of such...
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Tuning transfer function of fiber-optic Fabry-Pérot interferometer via introduction of birefringence in the cavity
PublicationThe study investigates the impact of birefringence exhibited by the cavity material of a fiber-optic Fabry-Pérot interferometer on its transfer function. The theoretical approach to analyze the effect of birefringence in the cavity of a plane Fabry-Pérot interferometer is described. The case of high- and low-finesse interferometer is investigated. It is shown that introduction of a birefringent medium of optimized parameters can...
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Spectral reflectance and transmission modeling of multi-cavity Fabry-Pérot interferometer with ZnO thin films
PublicationIn this paper spectral reflectance and transmission of a low-coherence fiber-optic Fabry-Pérot interferometer with thin ZnO layers is analyzed using a multi-cavity approach. In the investigated setup two standard single-mode optical fibers (SMF-28) with thin ZnO films deposited on their end-faces form an extrinsic Fabry-Pérot interferometer with air cavity. Calculations of the spectral response of the interferometer were performed...
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Polarization interferometer using a Liquid Crystalline Polymer waveplate for wavelength measurement
PublicationA two-beam polarization interferometer for measuring wavelength changes of a tunable semiconductor laser was designed, built and tested. This interferometer uses a λ/8 waveplate made from Liquid Crystalline Polymer in order to generate two output signals in quadrature. The λ/8 waveplate can be manufactured either on a beamsplitter face or on the mirror surface, reducing the cost and complexity of the optomechnical assembly. Experiment...
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The optimal construction of fiber-optic Fabry-Perot interferometer
PublicationTematem artykułu jest optymalizacja sensorów światłowodowych, wykorzystujących interferometer Fabry-Perota, pracujących w modzie odbiciowym. Celem optymalizacji była maksymalizacja rozdzielczości i dokładności sensora. Autorzy przedstawili analizę teoretyczną oraz wyniki eksperymentalnej optymalizacji światłowodowego interferometru Fabry-Perota, zaprojektowanego i zrealizowanego w laboratorium KOiSE PG.
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Coherent-wave Monte Carlo method for simulating light propagation in tissue
PublicationSimulating propagation and scattering of coherent light in turbid media, such as biological tissues, is a complex problem. Numerical methods for solving Helmholtz or wave equation (e.g. finite-difference or finite-element methods) require large amount of computer memory and long computation time. This makes them impractical for simulating laser beam propagation into deep layers of tissue. Other group of methods, based on radiative...
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Simulating coherent light propagation in a random scattering materials using the perturbation expansion
PublicationMultiple scattering of a coherent light plays important role in the optical metrology. Probably the most important phenomenon caused by multiple scattering are the speckle patterns present in every optical imaging method based on coherent or partially coherent light illumination. In many cases the speckle patterns are considered as an undesired noise. However, they were found useful in various subsurface imaging methods such as...
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Optimization of a Fabry-Perot Sensing Interferometer design for an optical fiber sensor of hematocrit level
PublicationContinuous measurement of the hemato crit level in blo o d can p otentially b e p erformed using optical bre sensors. The FabryPerot interferometric sensors are a promising candidate in this application. The most imp ortant step in the design of the sensor is design of the sensing interferometer. Adequate cavity length and high interference contrast are two most imp ortant requirements in this application. The design metho d of...
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Application of boron-doped diamond film and ZnO layer in the Fabry-Pérot interferometer
PublicationIn this article there have been presented the use of boron-doped diamond films for sensor applications. The low-finesse Fabry-Pérot interferometer working in the reflective mode has been implemented. Two kinds of reflective layers have been elaborated: boron-doped diamond thin films and zinc-oxide (ZnO) layer. Thin ZnO layers were deposited by Atomic Layer Deposition (ALD) on the face of a standard telecommunication single-mode...
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Temperature Sensors Based on Polymer Fiber Optic Interferometer
PublicationTemperature measurements are of great importance in many fields of human activities, including industry, technology, and science. For example, obtaining a certain temperature value or a sudden change in it can be the primary control marker of a chemical process. Fiber optic sensors have remarkable properties giving a broad range of applications. They enable continuous real-time temperature control in difficult-to-reach areas, in...
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Nitrogen-doped diamond thin films: potential application in Fabry-Pérot interferometer
PublicationIn this paper we present results of preliminary research of using nitrogen-doped diamond (NDD) films as reflective layer in Fabry-Pérot interferometer. NDD films were deposited on Si substrates by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) with the use of CH4, H2 and N2 gas mixtures. During deposition process methane flow rate varied while nitrogen flow was constant. We performed series of measurements which showed...
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Response of a fiber-optic Fabry-Pérot interferometer to refractive index and absorption changes – modelling and experiments
PublicationThis paper describes how the refractive index and the absorption of investigated substances change the spectrum of the optical radiation at the output of the fiber-optic Fabry-Pérot interferometer. The modeling of the operation of the interferometer takes into account not only the spectra of the refractive index and the absorption of the medium that is inside the cavity, but also spectra of the refractive indices of the core and...
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Application of the Fractional Fourier Transform for dispersion compensation in signals from a fiber-based Fabry-Perot interferometer
PublicationOptical methods of measurement do not require contact of a probe and the object under study, and thus have found use in a broad range of applications such as nondestructive testing (NDT), where noninvasive measurement is crucial. Measuring the refractive index of a material can give a valuable insight into its composition. Low‑coherence radiation sources enable measurement of the sample’s properties across a wide spectrum, while...
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In-situ monitoring of electropolymerization processes at boron-doped diamond electrodes by Mach-Zehnder interferometer
PublicationIn this work, the Mach-Zehnder interferometer was designed to monitor the electrochemical processes conducted at boron-doped diamond electrode surface. The diamond electrodes were synthesized via Microwave Plasma-Assisted Chemical Vapor Deposition on optical grade quartz glass. The achieved transmittance in working are of diamond electrodes reached 55 %. A cage system-based Mach-Zehnder interferometer was used which allowed the...
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Simulating propagation of coherent light in random media using the Fredholm type integral equation
PublicationStudying propagation of light in random scattering materials is important for both basic and applied research. Such studies often require usage of numerical method for simulating behavior of light beams in random media. However, if such simulations require consideration of coherence properties of light, they may become a complex numerical problems. There are well established methods for simulating multiple scattering of light (e.g....
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Człowiek zanurzony w rzeczywistości wirtualnej na przykładzie Laboratorium Zanurzonej Wizualizacji Przestrzennej
PublicationArtykuł opisuje Laboratorium Zanurzonej Wizualizacji Przestrzennej (LZWP), które umożliwia swobodną podróż w czasie i przestrzeni. Jego podstawowym wyposażeniem jest jaskinia rzeczywistości wirtualnej, czyli pomieszczenie o ścianach, suficie i podłodze stanowiących ekrany projekcyjne, wyświetlające generowane komputerowo obrazy 3D, tworzące spójny widok jednej sceny. Człowiek znajdujący się w takiej jaskini jest zatem zanurzony...
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Coherent electron transport in hydrocarbon molecular devices
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Low-coherence method of hematocrit measurement
PublicationDuring the last thirty years low-coherence measurement methods have gained popularity because of their unique advantages. Low-coherence interferometry, low-coherence reflectometry and low-coherence optical tomography offer resolution and dynamic range of measurement at the range of classical optical techniques. Moreover, they enable measurements of the absolute value of the optical path differences, which is still an unsolved problem...
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Tailoring the optical parameters of optical fiber interferometer with dedicated boron-doped nanocrystalline diamond thin film
PublicationOptical fiber interferometer using nanocrystalline boron-doped diamond film was investigated. The diamond films were deposited on glass plates using a Microwave Plasma-Enhanced Chemical Vapour Deposition (μPE CVD) sys-tem. The growth time was 3h, with boron doping level of 10 000 ppm producing films (B-NCD-10) of thickness ~ 200 nm. The presence of boron atoms in the diamond film is evident in Raman spectrum as peaks at 1212 cm-1...
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Biophotonic low-coherence sensors with boron-doped diamond thin layer
PublicationLow-coherence sensors using Fabry-Perot interferometers are finding new applications in biophotonic sensing, especially due to the rapid technological advances in the development of new materials. In this paper we discuss the possibility of using boron-doped nanodiamond layers to protect mirror in a Fabry-Perot interferometer. A low-coherence sensor using Fabry-Perot interferometer with a boron-doped nanodiamond (B-NCD) thin protective...
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Theoretical and experimental investigation of Optical Coherent Tomography topologies
PublicationW artykule przedstawiono teoretyczną i eksperymentalną analizę konfiguracji interferometrów w układach koherentnego tomografu optycznego. Zaprezentowano zrealizowany układ, którego specjalnie zaprojektowana konfiguracja pozawala na analizę zmian polaryzacji sygnału pomiarowego.
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Spectroscopic analysis for polarization sensitive optical coherent tomography
PublicationW artykule przedstawiono właściwości oraz ograniczenia optycznej tomografii koherentnej z analizą stanu polaryzacji promieniowania optycznego. Zaproponowano nową spektroskopową metodę analizy sygnału pomiarowego w PS-OCT oraz przedstawiono i omówiono zalety nowego rozwiązania na bazie uzyskanych wyników pomiarowych.
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The use of thin diamond films in fiber optic low-coherence interferometers”
PublicationIn this paper we present the use of thin diamond films in fiber-optic low-coherence interferometers. Two kinds of diamond surfaces were used: undoped diamond film and boron-doped diamond film. They were deposited on glass plates as well as silicon layers. A conventionally used mirror was used as a reference layer. Diamond films were deposited using Microwave Plasma Enhanced Chemical Vapour Deposition (μPE CVD) system. Measurements...
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Electronic correlations in coherent transport through a two quantum dot system
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Ultrahigh-resolution detection techniques for biomedical applications of optical coherent tomography.
PublicationOptyczne metody pomiarowe odgrywają w ostatnich latach coraz większą rolę w badaniach i diagnostyce medycznej. Mają one szereg zalet, do których zaliczyć można odporność na promieniowanie elektromagnetyczne, bezinwazyjność, bezpieczeństwo pomiaru oraz wysoką rozdzielczość. Jedną z najważniejszych technik stosowanych w diagnostyce medycznej jest koherentna tomografia optyczna (OCT). Jest to wysokorozdzielcza metoda obrazowania wewnętrznych...
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Response of a New Low-Coherence Fabry-Perot Sensor to Hematocrit Levels in Human Blood
PublicationIn this paper, a low-coherence Fabry-Perot sensor with a spectrally measured signal processing response to the refractive index of liquids is presented. Optical fiber sensors are potentially capable of continuous measuring hematocrit levels in blood. Low-coherence Fabry-Perot interferometric sensors offer a robust solution, where information about the measurand is encoded in the full spectrum of light reflected from the sensing...
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Combined Long-Period Fiber Grating and Microcavity In-Line Mach–Zehnder Interferometer for Refractive Index Measurements with Limited Cross-Sensitivity
PublicationThis work discusses sensing properties of a long-period grating (LPG) and microcavity in-line Mach–Zehnder interferometer (µIMZI) when both are induced in the same single-mode optical fiber. LPGs were either etched or nanocoated with aluminum oxide (Al2O3) to increase its refractive index (RI) sensitivity up to ≈2000 and 9000 nm/RIU, respectively. The µIMZI was machined using a femtosecond laser as a cylindrical cavity (d = 60...
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Stability of an optical displacement sensor using a two-beam polarization interferometer
PublicationW artykule przedstawiono wyniki pomiarów stabilności wybranej konfiguracji dwuwiązkowego interferometru polaryzacyjnego. Przedyskutowano źródła występującej niestabilności.
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The role of low-energy electrons in the charging process of LISA test masses
PublicationThe estimate of the total electron yield is fundamental for our understanding of the test-mass charging associated with cosmic rays in the Laser Interferometer Space Antenna (LISA) Pathfinder mission and in the forthcoming gravitational wave observatory LISA. To unveil the role of low energy electrons in this process owing to galactic and solar energetic particle events, in this work we study the interaction of keV and sub-keV...
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<title>Ultrahigh-resolution detection techniques for biomedical applications of optical coherent tomography</title>
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<title>Modeling of broadband light source to use with optical coherent tomography system</title>
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Non-destructive inspection of anti-corrosion protective coatings using optical coherent tomography
PublicationW artykule przedstawiono zastosowanie optycznej tomografii koherentnej (OCT) do badania antykorozyjnych powłok ochronnych. Omówiono właściwości optycznej interferometrii niskokoherentnej jako zastosowanej metody pomiarowej, opisano budowę pomiarowego systemu OCT, zbudowanego w Katedrze Metrologii i Optoelektroniki WETI PG. Przy pomocy zrealizowanego systemu przebadano grupę powierzchni metalicznych pokrytych różnymi powłokami antykorozyjnymi....
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ALD thin ZnO layer as an active medium in a fiber-optic Fabry–Perot interferometer
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ALD thin ZnO layer as an active medium in a fiber-optic Fabry-Perot interferometer
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Low-coherence photonic method of electrochemical processes monitoring
PublicationWe present an advanced multimodality characterization platform for simultaneous optical and electrochemical measurements of ferrocyanides. Specifcally, we combined a fber-optic Fabry– Perot interferometer with a three-electrode electrochemical setup to demonstrate a proof-ofprinciple of this hybrid characterization approach, and obtained feasibility data in its monitoring of electrochemical reactions in a boron-doped diamond flm...
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Low-Voltage Low-Power Filters with Independent ω0 and Q Tuning for Electronic Cochlea Applications
PublicationAn acoustic second-order low-pass filter is proposed for filter banks emulating the operation of a human cochlea. By using a special filter structure and an innovative quality (Q)-factor tuning technique, an independent change of the cutoff frequency (ω0) and the Q-factor with unchanged gain at low frequencies is achieved in this filter. The techniques applied result in a simple filter design with low Q-factor sensitivity to component...
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Laser beam angular stabilization system based on a compact interferometer and a precise double-wedge deflector
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LOW NOISE TIRES FOR HYBRID AND ELECTRIC VEHICLES
PublicationLow Emission Vehicles that are hybrid and electric cars may benefit from specially designed tires that are optimized for driving conditions typical for such vehicles. It is possible that in the future Low Emission Vehicles, especially passenger cars, will substitute conventional vehicles in all applications, however for the time being they are mostly used in urban and suburban areas. Urban traffic has a rather low demand for grip...