Showing papers on "Interferometry published in 2014"
TL;DR: In this paper, a silicon-on-insulator device combining two four-wave mixing photon-pair sources in an interferometer with a reconfigurable phase shifter is used to create and manipulate non-degenerate or degenerate, path-entangled or path-unentangled photon pairs.
Abstract: A silicon-on-insulator device combining two four-wave-mixing photon-pair sources in an interferometer with a reconfigurable phase shifter is used to create and manipulate non-degenerate or degenerate, path-entangled or path-unentangled photon pairs. A quantum interference visibility of nearly 100% is observed on-chip. This device is a first step towards fully integrated quantum technologies.
522 citations
Book•
09 Dec 2014
TL;DR: In this paper, the authors present a survey of applications of PIR in matrix algebra and matrix algebra, including unitary and rotation groups, and coherent stochastic signal analysis.
Abstract: 1. Polarised Electromagnetic Waves 2. Depolarisation and Scattering Entropy 3. Depolarisation in Surface and Volume Scattering 4. Decomposition Theorems 5. Introduction to Radar Interferometry 6. Polarimetric Interferometry 7. Coherence Variation for Surface and Volume Scattering 8. Parameter Estimation using Polarimetric Interferometry 9. Applications of Polarimetry and Interferometry Appendix 1: Introduction to Matrix Algebra Appendix 2: Unitary and Rotation Groups Appendix 3: Coherent Stochastic Signal Analysis
407 citations
TL;DR: This work studies a new type of interferometer in which the beam splitting and recombination elements are parametric amplifiers, and observes an improvement of 4.1±0.3 dB in signal-to-noise ratio.
Abstract: Interferometers play a key role in precision measurements and metrology. Here, the authors demonstrate a new type of interferometer that replaces the standard beam splitter elements with parametric amplifiers, which provides enhanced performance compared with a Mach–Zehnder interferometer.
370 citations
TL;DR: In this article, an on-chip silicon-based Ramsey-type interferometer has been used to probe the phase of photonic states and experimentally observe an effective magnetic flux between 0 and 2π corresponding to a non-reciprocal 2π phase shift with an inter-ometer length of 8.35 mm and an interference-fringe extinction ratio of 2.4 dB.
Abstract: Photons are neutral particles that do not interact directly with a magnetic field. However, recent theoretical work has shown that an effective magnetic field for photons can exist if the phase of light changes with its direction of propagation. This direction-dependent phase indicates the presence of an effective magnetic field, as shown experimentally for electrons in the Aharonov–Bohm experiment. Here, we replicate this experiment using photons. To create this effective magnetic field we construct an on-chip silicon-based Ramsey-type interferometer. This interferometer has been traditionally used to probe the phase of atomic states and here we apply it to probe the phase of photonic states. We experimentally observe an effective magnetic flux between 0 and 2π corresponding to a non-reciprocal 2π phase shift with an interferometer length of 8.35 mm and an interference-fringe extinction ratio of 2.4 dB. This non-reciprocal phase is comparable to those of common monolithically integrated magneto-optical materials.
344 citations
Book•
01 Jan 2014
TL;DR: In this paper, Lopez et al. presented an overview of the development and application of optical fibre sensors in light and waveguiding applications, as well as their application in industrial applications.
Abstract: PART ONE: PRELIMINARY OVERVIEW Introduction to Fibre Optic Sensing Technology (J.M. Lopez--Higuera) The Commercialisation of Fibre Optic Sensors (S.D. Crossley) PART TWO: FUNDAMENTALS OF PHOTONICS AND COMPONENTS FOR SENSING Light and Waveguiding (J.L. Arce--Diego) Optical Waveguides and their Manufacture (J. Zubia and M. Lomer) Passive Bulk Optical Components for Sensing (C. Gomez--Reino, V. Perez and C. Bao) Fibre and Integrated Optic Components for Sensing (R. Willsch and W. Ecke) Semiconductor Optical Sources for Sensing Technology (I. Esquivias and J. Arias) Photodetectors for Sensing (J.M. Lopez--Higuera and J. Madruga) Optical Amplifiers (M.A. Rebolledo and M. Lopez--Amo) Superfluorescent Fibre Optic Sources (J.M. Lopez--Higuera) PART THREE: PRINCIPLES AND TECHNIQUES FOR SENSING Transduction Techniques based on Intensity Modulation of Light (A.C. Garcia and J. Echevarria Cuenca) Interferometry and Polarimetry for Optical Sensing (DC. Jones) Gas Spectroscopy Techniques for Optical Fibre Sensors (B. Culshaw) Distributed Optical--fibre Sensing (A. Rogers) Principles of Laser Doppler Velocimetry (D.A. Jackson and C.N. Pannell) Fibre Gyroscope Principles (S. Merlo, M. Norgia and S. Donati) Fibre Grating Technology: Theory, Photosensitivity, Fabrication and Characterization (R. Khasyap and J.M. Lopez--Higuera) Fibre Bragg Grating Interrogation Techniques (J.L. Santos and W.N. MacPherson) Discrimination Techniques for Optical Sensors (J.D.C. Jones and W.N. MacPherson) Optical Reliability of Fibre Gratings (S. Kannan and P. Lemaire) Passive Fibre Optic Sensor Networks (A. Dandridge and C. Kirkendall) Active Fibre Optic Sensor Networks (S. Abad, M. Lopez--Amo and I.R. Matias) PART FOUR: APPLICATIONS Optical Fibre Gratings Applications (S.T. Vohra) Laser Doppler Velocimetry Applications (D.A. Jackson and C.N. Pannell) Phototonic Sensing Technology in Civil Engineering Applications (D. Inaudi) Applications of Optical Fibre Sensors for the Nuclear Power Industry (P. Ferdinand and S. Magne) Optical Fibre Current and Voltage Sensors for the Electric Power Industry (A.H. Rose and G.W. Day) Fibre Optic Gyroscope for Industrial Applications (T. Kumagai and H. Kajioka) Optical Fibre Sensors for Fly--By--Light Aircraft (M. Kobayashi and K. Toyama) Optical Fibre Sensing of Electrical Discharges and Plasmas (G. Woolsey) Fibre Optic Sensors for Oilfield Services (R.J. Schroeder, R.T. Ramos, T. Yamate and E. Udd) Fibre Optic Biosensors (C.A. Rowe--Taitt and F.S. Ligler) Biomedical Fibre Optic Sensors (F. Baldini and A.G. Mignani) Fibre Optic Sensors for Environmental Applications (G. Holst and B. Mizaikoff) The Optical Nose (D. Walt and S. Stitzel) A New Approach to optical Fibre Sensing Techniques based on the Sensory Systems of Living Bodies (J.A. Martin--Pereda and A.P. Gonzalez--Marcos) Acronyms. Index.
332 citations
TL;DR: A wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications in a study on interferometric optical fiber sensors.
Abstract: Optical fibers have been involved in the area of sensing applications for more than four decades. Moreover, interferometric optical fiber sensors have attracted broad interest for their prospective applications in sensing temperature, refractive index, strain measurement, pressure, acoustic wave, vibration, magnetic field, and voltage. During this time, numerous types of interferometers have been developed such as Fabry-Perot, Michelson, Mach-Zehnder, Sagnac Fiber, and Common-path interferometers. Fabry-Perot interferometer (FPI) fiber-optic sensors have been extensively investigated for their exceedingly effective, simple fabrication as well as low cost aspects. In this study, a wide variety of FPI sensors are reviewed in terms of fabrication methods, principle of operation and their sensing applications. The chronology of the development of FPI sensors and their implementation in various applications are discussed.
291 citations
TL;DR: The present review collects the most relevant developments of the past twenty years categorizing them into two main groups, such as common- and double path waveguide interferometers and the diverse sensor designs in order to contrast the advantages and disadvantages of the different approaches and sensor families.
258 citations
TL;DR: In this paper, the authors describe the spherical harmonic transit telescope through the use of a novel formalism for the analysis of transit radio telescopes, which is particularly well suited to wide-field radio interferometers.
Abstract: In this paper, we describe the spherical harmonic transit telescope through the use of a novel formalism for the analysis of transit radio telescopes. This all-sky approach bypasses the curved-sky complications of traditional interferometry and so is particularly well-suited to the analysis of wide-field radio interferometers. It enables compact and computationally efficient representations of the data and its statistics, which allow new ways of approaching important problems like map-making and foreground removal. In particular, we show how it enables the use of the Karhunen-Loeve transform as a highly effective foreground filter, suppressing realistic foreground residuals for our fiducial example by at least a factor 20 below the 21 cm signal, even in highly contaminated regions of the sky. This is despite the presence of the mode-mixing inherent in real-world instruments with frequency-dependent beams. We show, using Fisher forecasting, that foreground cleaning has little effect on power spectrum constraints compared to hypothetical foreground-free measurements. Beyond providing a natural real-world data analysis framework for 21 cm telescopes now under construction and future experiments, this formalism allows accurate power spectrum forecasts to be made that include the interplay of design constraints and realistic experimental systematics with 21st century 21 cm science.
197 citations
TL;DR: An interferometer with a levitated, optically cooled and then free-falling silicon nanoparticle in the mass range of one million atomic mass units, delocalized over >150 nm is proposed and indicates that this is a viable route towards macroscopic high-mass superpositions using available technology.
Abstract: Testing the validity of the quantum superposition principle with increasingly large particles may shed light on the quantum to classical transition for macroscopic objects. Here, Bateman et al. propose a near-field interference scheme based on the single-source Talbot effect for 106 amu silicon particles.
186 citations
TL;DR: An experiment in which neutrons are sent through a perfect silicon crystal interferometer and weak measurements are performed to probe the location of the particle and its magnetic moment suggests that the system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other.
Abstract: From its very beginning, quantum theory has been revealing extraordinary and counter-intuitive phenomena, such as wave-particle duality, Schrodinger cats and quantum non-locality. Another paradoxical phenomenon found within the framework of quantum mechanics is the 'quantum Cheshire Cat': if a quantum system is subject to a certain pre- and postselection, it can behave as if a particle and its property are spatially separated. It has been suggested to employ weak measurements in order to explore the Cheshire Cat's nature. Here we report an experiment in which we send neutrons through a perfect silicon crystal interferometer and perform weak measurements to probe the location of the particle and its magnetic moment. The experimental results suggest that the system behaves as if the neutrons go through one beam path, while their magnetic moment travels along the other.
181 citations
TL;DR: A high-sensitivity strain sensor based on an in-fiber Fabry-Perot interferometer (FPI) with an air cavity, which was created by splicing together two sections of standard single-mode fibers, is demonstrated.
Abstract: We demonstrated a high-sensitivity strain sensor based on an in-fiber Fabry–Perot interferometer (FPI) with an air cavity, which was created by splicing together two sections of standard single-mode fibers. The sensitivity of this strain sensor was enhanced to 6.0 pm/μe by improving the cavity length of the FPI by means of repeating arc discharges for reshaping the air cavity. Moreover, such a strain sensor has a very low temperature sensitivity of 1.1 pm/°C, which reduces the cross sensitivity between tensile strain and temperature.
TL;DR: A regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses is predicted and confirmed by measurement of pulse power statistics at the output of the interferometer.
Abstract: We demonstrate a high bit-rate quantum random number generator by interferometric detection of phase diffusion in a gain-switched DFB laser diode. Gain switching at few-GHz frequencies produces a train of bright pulses with nearly equal amplitudes and random phases. An unbalanced Mach-Zehnder interferometer is used to interfere subsequent pulses and thereby generate strong random-amplitude pulses, which are detected and digitized to produce a high-rate random bit string. Using established models of semiconductor laser field dynamics, we predict a regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These are confirmed by measurement of pulse power statistics at the output of the interferometer. Using a 5.825 GHz excitation rate and 14-bit digitization, we observe 43 Gbps quantum randomness generation.
TL;DR: The solitonic matter wave is found to significantly increase fringe visibility even compared with a noninteracting cloud and across a range of s-wave scattering values including repulsive, attractive and nonInteracting values.
Abstract: We present the first realization of a solitonic atom interferometer. A Bose-Einstein condensate of $1\ifmmode\times\else\texttimes\fi{}{10}^{4}$ atoms of rubidium-85 is loaded into a horizontal optical waveguide. Through the use of a Feshbach resonance, the $s$-wave scattering length of the $^{85}\mathrm{Rb}$ atoms is tuned to a small negative value. This attractive atomic interaction then balances the inherent matter-wave dispersion, creating a bright solitonic matter wave. A Mach-Zehnder interferometer is constructed by driving Bragg transitions with the use of an optical lattice colinear with the waveguide. Matter-wave propagation and interferometric fringe visibility are compared across a range of $s$-wave scattering values including repulsive, attractive and noninteracting values. The solitonic matter wave is found to significantly increase fringe visibility even compared with a noninteracting cloud.
TL;DR: In this study, two-dimensional interferometer observations of a classic bilevel intracloud flash are presented and combined with three-dimensional Lightning Mapping Array observations to produce a quasi 3-D map of lightning activity with the time resolution of the interferometers.
Abstract: The VHF Broadband Digital Interferometer developed by Osaka University has been improved to allow continuous sampling over the entire duration of a lightning flash and to utilize a generalized cross-correlation technique for determining the lightning source directions. Time series waveforms of 20-80 MHz signals received at three orthogonally located antennas are continuously digitized over multisecond intervals, as opposed to sequences of short-duration triggers. Because of the coherent nature of the measurements, radiation sources are located down into the ambient receiver and environmental noise levels, providing a quantum leap in the ability to study lightning discharge processes. When postprocessed using cross correlation, the measurements provide angular uncertainties less than 1 ! and time resolution better than 1!s. Special techniques have been developed to distinguish between actual lightning sources and noise events, with the result being that on the order of 50,000-80,000 radiation sources are located for a typical lightning flash. In this study, two-dimensional interferometer observations of a classic bilevel intracloud flash are presented and combined with three-dimensional Lightning Mapping Array observations to produce a quasi 3-D map of lightning activity with the time resolution of the interferometer. As an example of the scientific utility of the observations, results are presented for the 3-D progression speed of negative leaders associated with intracloud K-leaders.
TL;DR: In this article, an all-fiber sensor for simultaneous measurement of refractive index and temperature in solutions is proposed and demonstrated, which contains a core-offered Mach-Zehnder interferometer and a fiber Bragg grating (FBG).
Abstract: An all-fiber sensor for simultaneous measurement of refractive index and temperature in solutions is proposed and demonstrated. The sensing head contains a core-offset Mach–Zehnder interferometer (MZI) and a fiber Bragg grating (FBG). The interference fringe of the MZI and the Bragg wavelength of the FBG would shift with the variation of the ambient refractive index (RI) and/or temperature. The experimental results show that the RI sensitivity and the temperature sensitivity for the sensor are 13.7592 nm/RI and 0.0462 nm/°C, respectively. Its low fabrication cost, simple configuration and high sensitivity will have attractive potential applications in chemical and biological sensing.
TL;DR: This work uses phase-sensitive, three-dimensional optical coherence tomography (OCT) to probe the nanometer-to-micrometer-scale axial displacements in tissues induced by compressive loading to reveal micro-scale mechanical contrast in human breast and lymph node tissues.
Abstract: We present optical coherence micro-elastography, an improved form of compression optical coherence elastography. We demonstrate the capacity of this technique to produce en face images, closely corresponding with histology, that reveal micro-scale mechanical contrast in human breast and lymph node tissues. We use phase-sensitive, three-dimensional optical coherence tomography (OCT) to probe the nanometer-to-micrometer-scale axial displacements in tissues induced by compressive loading. Optical coherence micro-elastography incorporates common-path interferometry, weighted averaging of the complex OCT signal and weighted least-squares regression. Using three-dimensional phase unwrapping, we have increased the maximum detectable strain eleven-fold over no unwrapping and the minimum detectable strain is 2.6 μe. We demonstrate the potential of mechanical over optical contrast for visualizing micro-scale tissue structures in human breast cancer pathology and lymph node morphology.
TL;DR: In this paper, the authors study the simultaneous estimation of two parameters related to optical interferometry: phase and loss, using a fixed number of photons and derive a tradeoff in the estimation of these two parameters which shows that it is impossible to design a strategy saturating the quantum Cram\'er-Rao bound for loss and phase estimation in a single setup simultaneously.
Abstract: Interferometry with quantum light is known to provide enhanced precision for estimating a single phase. However, depending on the parameters involved, the quantum limit for the simultaneous estimation of multiple parameters may not be attainable, leading to tradeoffs in the attainable precisions. Here we study the simultaneous estimation of two parameters related to optical interferometry: phase and loss, using a fixed number of photons. We derive a tradeoff in the estimation of these two parameters which shows that, in contrast to single-parameter estimation, it is impossible to design a strategy saturating the quantum Cram\'er-Rao bound for loss and phase estimation in a single setup simultaneously. We design optimal quantum states with a fixed number of photons achieving the best possible simultaneous precisions. Our results reveal general features about concurrently estimating Hamiltonian and dissipative parameters and have implications for sophisticated sensing scenarios such as quantum imaging.
TL;DR: In this paper, a method for detecting many-body localization (MBL) in disordered spin systems is proposed, which involves pulsed coherent spin manipulations that probe the dephasing of a given spin due to its entanglement with a set of distant spins.
Abstract: We propose a method for detecting many-body localization (MBL) in disordered spin systems. The method involves pulsed coherent spin manipulations that probe the dephasing of a given spin due to its entanglement with a set of distant spins. It allows one to distinguish the MBL phase from a noninteracting localized phase and a delocalized phase. In particular, we show that for a properly chosen pulse sequence the MBL phase exhibits a characteristic power-law decay reflecting its slow growth of entanglement. We find that this power-law decay is robust with respect to thermal and disorder averaging, provide numerical simulations supporting our results, and discuss possible experimental realizations in solid-state and cold-atom systems.
TL;DR: In this paper, the state-of-the-art optical Sagnac interferometers for inertial guidance and geophysics are compared with two-photon Raman transitions for manipulation of atomic wave packets.
TL;DR: An all-optical approach for controlling the phase of a flow of cavity-polaritons, making use of their strong interactions with localized excitons is proposed, by implementing a compact exciton–polariton interferometer, which output intensity and polarization can be optically controlled.
Abstract: Quantum fluids based on light is a highly developing research field, since they provide a nonlinear platform for developing optical functionalities and quantum simulators. An important issue in this context is the ability to coherently control the properties of the fluid. Here we propose an all-optical approach for controlling the phase of a flow of cavity-polaritons, making use of their strong interactions with localized excitons. Here we illustrate the potential of this method by implementing a compact exciton–polariton interferometer, which output intensity and polarization can be optically controlled. This interferometer is cascadable with already reported polariton devices and is promising for future polaritonic quantum optic experiments. Complex phase patterns could be also engineered using this optical method, providing a key tool to build photonic artificial gauge fields.
Book•
18 Aug 2014
TL;DR: In this article, a list of linear phase-shifting algorithms (PSAs) for digital linear systems is presented, including the Carre algorithm, the minimum 3-step PSA, and the least-squares PSAs.
Abstract: Chapter 1 Digital Linear Systems 1.1 Introduction 1.2 Digital Sampling 1.3 Linear time-invariant (LTI) systems 1.4 Z-transform analysis of digital linear systems 1.5 Fourier analysis of digital linear systems 1.6 Convolution one-dimensional digital filters 1.7 Convolution two-dimensional linear filters 1.8 Linear regularized filtering techniques 1.9 Stochastic processes 1.10 Linear quadrature filters Chapter 2 Synchronous Temporal Interferometry 2.1 Introduction 2.2 The temporal carrier interferometric signal 2.3 Quadrature linear filters for phase estimation 2.4 The minimum 3-step PSA 2.5 Least-squares PSAs 2.6 Detuning in temporal interferometry 2.7 Noise in temporal interferometry 2.8 Harmonics in temporal interferometry 2.9 Quadrature filters design by 1st-order building blocks 2.10 Some further topics in linear PSAs theory Chapter 3 Asynchronous Temporal Interferometry 3.1 Introduction 3.2 Spectral analysis of the Carre algorithm 3.3 Spectral analysis of other self-tunable PSAs 3.4 Self-calibrating PSAs Chapter 4 Spatial Methods with Carrier 4.1 Introduction 4.2 Linear spatial carrier 4.3 Circular spatial carrier interferogram 4.4 2D Pixelated Spatial Carrier 4.5 Regularized Quadrature Filters 4.6 Relation Between Temporal and Spatial Analysis Chapter 5 Spatial Methods without Carrier 5.1 Introduction 5.2 Phase demodulation of closed-fringe interferograms 5.3 The Regularized Phase Tracker (RPT) 5.4 Local Robust Quadrature Filters 231 5.5 2D Fringe Direction 5.6 2D Vortex Filter 5.7 The General Quadrature Transform Chapter 6 Phase Unwrapping 6.1 Introduction 6.2 Phase unwrapping with by 1D line integration 6.3 Phase unwrapping with 1D IIR filters 6.4 1D phase unwrapping with linear prediction 6.5 2D phase unwrapping with linear prediction 6.6 Least-squares method for phase unwrapping 6.7 Phase unwrapping through demodulation using a phase tracker 6.8 Smooth unwrapping with 2D detection of phase inconsistencies 6.9 Quality Maps and Branch Cut Methods Appendix List of linear phase-shifting algorithms (PSAs)
TL;DR: A novel fiber in-line Mach-Zehnder interferometer with a large fringe visibility of up to 17 dB, which was fabricated by misaligned splicing a short section of thin core fiber between two sections of standard single-mode fiber could be used to realize simultaneous measurement of tensile strain and temperature.
Abstract: We demonstrated a novel fiber in-line Mach-Zehnder interferometer (MZI) with a large fringe visibility of up to 17 dB, which was fabricated by misaligned splicing a short section of thin core fiber between two sections of standard single-mode fiber. Such a MZI could be used to realize simultaneous measurement of tensile strain and temperature. Tensile strain was measured with an ultrahigh sensitivity of −0.023 dB/μɛ via the intensity modulation of interference fringes, and temperature was measured with a high sensitivity of 51 pm/°C via the wavelength modulation of interference fringe. That is, the MZI-based sensor overcomes the cross-sensitivity problem between tensile strain and temperature by means of different demodulation methods. Moreover, this proposed sensor exhibits the advantages of low-cost, extremely simple structure, compact size (only about 10 mm), and good repeatability.
TL;DR: An optical holographic micro-tomographic technique for imaging both the three-dimensional structures and dynamics of biological cells and measurements of morphological, chemical, and mechanical parameters at the individual cell level is presented.
Abstract: We present an optical holographic micro-tomographic technique for imaging both the three-dimensional structures and dynamics of biological cells. Optical light field images of a sample, illuminated by a plane wave with various illumination angles, are measured in a common-path interferometry, and thus both the three-dimensional refractive index tomogram and two-dimensional dynamics of live biological cells are measured with extremely high sensitivity. The applicability of the technique is demonstrated through quantitative and measurements of morphological, chemical, and mechanical parameters at the individual cell level.
TL;DR: In this paper, the magneto-optical characteristic of the magnetic fluid was adopted to form a novel fiber-optic magnetic field sensor, which was composed of an extrinsic fiber Fabry-Perot interferometer and magnetic fluid.
Abstract: Magnetic fluid is a new type of optical functional material, which has interesting optical characteristics under an external magnetic field. In this letter, the magneto-optical characteristic of the magnetic fluid was adopted to form a novel fiber-optic magnetic field sensor. The sensor probe was composed of an extrinsic fiber Fabry-Perot interferometer and magnetic fluid. The refractive index of the magnetic fluid would be changed with the increase of magnetic field. Preliminary experiment was carried out to verify the feasibility of the sensor. The magnetic field measurement sensitivity was 0.0431 nm/Gs in the experiment. The measurement resolution was better than 0.5 Gs at the measurement range from 0 to 400 Gs. The sensor has the advantages of simple structure, compact size, and easy fabrication.
TL;DR: In this article, an all-optical NH3 gas sensor based on graphene/microfiber hybrid waveguide (GMHW) is presented, where the wavelength shift induced by the NH3 absorption is spectrally demodulated by using a microfiber-based Mach-Zehnder interferometer (MZI).
Abstract: In this paper, we report an all-optical NH3 gas sensor based on graphene/microfiber hybrid waveguide (GMHW). The study on the sensing mechanism shows that as the adsorption of NH3 modifies the conductivity of graphene and thus the effective refractive index of the GMHW, and the transmitting light along the GMHW is very sensitive to NH3 gas concentration. The wavelength shift induced by the NH3 absorption is spectrally demodulated by using a microfiber-based Mach–Zehnder interferometer (MZI). A high sensitivity of ∼6 pm/ppm is obtained for the NH3 adsorption measurement. The resolution of such a sensor is ∼0.3 ppm, mainly limited by the resolution of the optical spectrum analyzer used. The work of this paper may open a window for the development of novel GMHW-based gas sensors with high sensitivity, small footprint, easy fabrication and low cost.
TL;DR: The working principle of Mach–Zehnder interferometer is described and its efficient application to perform digital logic operations such as AND, XOR and XNOR logic gates is described.
TL;DR: A simple and cost-effective method is presented for quantitative phase imaging through attaching a compact filter set to the output port of an existing microscope through a common-path lateral phase shifting interferometer.
Abstract: A simple and cost-effective method is presented for quantitative phase imaging. A common-path lateral phase shifting interferometer is realized through attaching a compact filter set to the output port of an existing microscope. The working principles, design criteria, and limitations are also derived and explained. In order to demonstrate the capability and applicability of the method, the optical phase images of a microsphere and individual human red blood cells are measured with high stability.
TL;DR: Modulation of the scattered energy is observed by mapping the off-axis scattered optical signal: scattering is minimized at a node of the standing wave pattern and maximized at an antinode.
Abstract: We report the experimental observation of all-optical modulation of light in a graphene film. The graphene film is scanned across a standing wave formed by two counter-propagating laser beams in a Sagnac interferometer. Through a coherent absorption process the on-axis transmission is modulated with close to 80% efficiency. Furthermore, we observe modulation of the scattered energy by mapping the off-axis scattered optical signal: scattering is minimized at a node of the standing wave pattern and maximized at an antinode. The results highlight the possibility to switch and modulate any given optical interaction with deeply sub-wavelength films.
TL;DR: In this paper, the authors proposed a compact and ultrasensitive all-fiber temperature sensor based on an in-line fully liquid-filled photonic crystal fiber (PCF) Mach-Zehnder interferometer (MZI).
Abstract: We propose a compact and ultrasensitive all-fiber temperature sensor based on an in-line fully liquid-filled photonic crystal fiber (PCF) Mach-Zehnder interferometer (MZI). It consists of a small piece of index-guiding PCF fully infiltrated by fluid and two standard single-mode fibers offset spliced with PCF. Two core modes LP01 and LP11 are conveniently used as optical arms to form the in-line MZI-type interferometer. Experimental and theoretical investigations of its response to temperature confirm that high temperature sensitivity up to -1.83 nm/°C could be realized with such a compact interferometeric PCF temperature sensor.
TL;DR: In this article, the Brillouin Optical Time Domain Reflectometry (or Analysis) and the Rayleigh backscatter wavelength interferometry (OBR) were used to monitor and define ground displacement models through an appropriate 2D and 3D optimization and signal analysis of information derived from a horizontally laid fiber above the tunnel.