Mach-Zehnder Interferometer Method Research Articles

Mach–Zehnder interferometric analysis of planar polymer waveguide having an adlayer of WS2 for biosensing applications

Abstract To enhance the sensing performance of a four-layer planar polymer optical waveguide, an adlayer of tungsten disulfide material is introduced. Also, the proposed waveguide is used to demonstrate theoretically the detection of uric acid concentration in blood or urine. The heterostructure of two-dimensional WS2 offers excellent dry lubricity with respect to any other 2D substance, such as graphite or molybdenum disulfide. The proposed waveguide is analyzed using the common path Mach–Zehnder interferometric method. The dispersion characteristic i.e., the effective refractive indices and thickness of proposed waveguide is plotted for a particular wavelength range to optimize the thickness of film layer. The difference in propagation constant and output interference signal for changing the cover medium is calculated. Using the output interference signal, the phase sensitivity 213 degree/RIU is obtained in the proposed waveguide. The maximum obtained sensitivity, limit of detection and limit of quantification for uric acid concentration in the proposed waveguide structure is 6.86 × 10−2 degree mM−1, 0.061 mM and 0.203 mM, respectively.

A theoretical investigation of magnetic susceptibility measurement of diamagnetic liquids using a Mach–Zehnder interferometer

In this study, we present a novel method for measuring the magnetic susceptibility of liquids using a Mach–Zehnder interferometer. The proposed technique employs a ring magnet to deform the liquid, while a laser beam passes through the liquid to measure the resulting interference pattern. The deformation of the liquid, caused by the known magnetic field of the ring magnet, is used to calculate the magnetic susceptibility. We provide a comprehensive theoretical framework, including the relevant equations and models, for analyzing the data obtained using this method. We compare the Mach–Zehnder interferometer method with other established techniques, highlighting its advantages and disadvantages. Our findings indicate that the Mach–Zehnder interferometer technique offers high accuracy, sensitivity, and potential applications in characterizing the magnetic properties of various liquid systems.

Hardware Error Correction for MZI-Based Matrix Computation.

With the rapid development of artificial intelligence, the electronic system has fallen short of providing the needed computation speed. It is believed that silicon-based optoelectronic computation may be a solution, where Mach-Zehnder interferometer (MZI)-based matrix computation is the key due to its advantages of simple implementation and easy integration on a silicon wafer, but one of the concerns is the precision of the MZI method in the actual computation. This paper will identify the main hardware error sources of MZI-based matrix computation, summarize the available hardware error correction methods from the perspective of the entire MZI meshes and a single MZI device, and propose a new architecture that will largely improve the precision of MZI-based matrix computation without increasing the size of the MZI's mesh, which may lead to a fast and accurate optoelectronic computing system.

Magneto-optical effects of MgFe2O4 nanoparticles in solutions and thin films of polystyrene using digital Mach-Zehnder interferometer: An optical based sensor for energy storage controller

In this work, the effects of magnetic fields on the refractive index profiles and induced birefringence of polystyrene/MgFe2O4 nanoparticles (15 nm) solutions and thin films were investigated. Both the refractive index and the induced birefringence profiles of the solutions and thin films were investigated as a function of the applied magnetic field strength using the digital two-beam Mach-Zehnder interferometric method. Image processing algorithm, based on the fast Fourier transform (FFT) analysis, was applied to extract the optical phase differences of the recorded micro-interferograms for all samples under investigation. Then the refractive index and birefringence profiles are calculated. A good correlation between the applied magnetic field and the change of refractive index (Δn) was obtained (R2~0.94). This could be useful for electric energy storage sensors based on the magneto-optical properties of polystyrene/MgFe2O4 solutions and thin films.

Sensitivity enhancement by using adlayer of MoS2 heterostructure in a common path Mach-Zehnder interferometer method for biochemical sensor

The heterostructure of two-dimensional MoS2 material are promising and useful in the field of biochemical sensors. In present communication, the sensitivity of a four-layer planar polymer optical waveguide having an ad-layer of MoS2 material is presented. A common path Mach-Zehnder interferometric method is used for biological sensing applications. The effective refractive indexes of fundamental modes (TE0, TM0) are obtained at considered wavelength range and the difference of their propagation constant is calculated. The output interference signal in presence of different cover medium shows maxima shift which are considered as sensing signal. The phase sensitivity is calculated by using this output interference signal which is 200/RIU.

The use of optical methods for measuring weak acoustic shock waves in homogeneous air and close to reflecting boundaries

Measuring blast waves in laboratory-scale experiments using acoustical methods is a challenge. Optical methods provide an attractive possibility for recording pressure signatures of weak acoustic shocks. In this presentation, recent experiments for reconstructing pressure waveforms of spark-generated spherically divergent blast waves (1.8 kPa amplitude and 50 μs duration at 15 cm distance from the source) both in homogeneous air and close to reflecting surfaces are overviewed. Three methods were employed: shadowgraphy, schlieren, and interferometry. It was shown that shadowgraphy method allowed for measuring shock thickness and its amplitude. Schlieren technique provided reconstruction of the pressure waveforms in homogeneous air. In the reconstruction process the front geometry was assumed to be spherical or cylindrical. The exposure time of the high-speed camera was a limiting factor for the time resolution. Mach-Zehnder interferometer method was the most relevant for laboratory-scale measurements. The method reached 0.4 μs of time resolution, which was more than 6 times higher than that of 1/8-in condenser microphones. Moreover, the Mach-Zehnder interferometry allowed quantitative reconstruction of the pressure waveform without additional calibrations. The method was successfully applied for measuring waveforms in homogeneous air and reflected waves from rigid smooth and rough surfaces. [Work supported by ANR-10-LABX-0060/ANR-16-IDEX-0005.]

Interferometric optical testing to discriminate benign and malignant brain tumors

When normal cells suffer from the malignant disease, changes occur in cellular size and structure, and their constituents. These changes can affect the biological response of cells and tissues. Conventional hematoxylin and eosin staining, which is the gold standard of tumor diagnosis provide a very detailed view of the tissue by staining cell structures to diagnose a disease based on the deformation of the cells. However, this study shows changes in cells and tissues structure due to malignant diseases can also affect the optical properties. The purpose of this research was to assess and compare these effects to identify benign and malignant brain tissues from each other. Various samples of adult human brain tissues were studied using Mach–Zehnder interferometer as an optical method and using the Fourier transform method as an analytical process. The formed interference patterns of benign and malignant brain tumors were investigated to obtain the phase distribution of tumors. The obtained information demonstrated that the phase distribution of malignant brain tissues was different from benign brain tissues. The phase distribution approximately ranged from 10 to 120 rad for benign samples and from 10 to 160 rad for malignant samples. Moreover, the average of unwrapped phase distribution was 63.79 and 85.69 rad in benign and malignant samples, respectively. This results indicated that the proposed laser-based technique, Mach–Zehnder interferometer method, can be used as an auxiliary procedure along with histological techniques to identify benign and malignant brain tumors from each other. It is suggested that the unwrapped phase distribution of tissues be considered as an optical property for differentiating various brain tumors.

Irregular reflection of spark-generated shock pulses from a rigid surface: Mach-Zehnder interferometry measurements in air.

The irregular reflection of weak acoustic shock waves, known as the von Neumann reflection, has been observed experimentally and numerically for spherically diverging waves generated by an electric spark source. Two optical measurement methods are used: a Mach-Zehnder interferometer for measuring pressure waveforms and a Schlieren system for visualizing shock fronts. Pressure waveforms are reconstructed from the light phase difference measured by the interferometer using the inverse Abel transform. In numerical simulations, the axisymmetric Euler equations are solved using finite-difference time-domain methods and the spark source is modeled as an instantaneous energy injection with a Gaussian shape. Waveforms and reflection patterns obtained from the simulations are in good agreement with those measured by the interferometer and the Schlieren methods. The Mach stem formation is observed close to the surface for incident pressures within the range of 800 to 4000 Pa. Similarly, as for strong shocks generated by blasts, it is found that for spherical weak shocks the Mach stem length increases with distance following a parabolic law. This study confirms the occurrence of irregular reflections at acoustic pressure levels and demonstrates the benefits of the Mach-Zehnder interferometer method when microphone measurements cannot be applied.

Mach–Zehnder interferometer implementation for thermo-optical and Kerr effect study

In this paper, we propose the Mach–Zehnder interferometric method for third-order nonlinear optical and thermo-optical studies. Both effects manifest themselves as refractive index dependence on the incident light intensity and are widely employed for multiple opto-optical and thermo-optical applications. With the implemented method, we have measured the Kerr and thermo-optical coefficients of chloroform under CW, ns and ps laser irradiance. The application of lasers with different light wavelengths, pulse duration and energy allowed us to distinguish the processes responsible for refractive index changes in the investigated solution. Presented setup was also used for demonstration of opto-optical switching. Results from Mach–Zehnder experiment were compared to Z-scan data obtained in our previous studies. Based on this, a quality comparison of both methods was assessed and advantages and disadvantages of each method were analyzed.

Electro-optic coefficients of a non-congruent lithium niobate fabricated by vapour transport equilibration: Composition effect

Abstract Composition effect on electro-optic (EO) properties of a LiNbO3 (LN) single-crystal has been investigated in a Li2O-content range of 47.0–49.95 mol%. Some non-congruent LN crystals with different Li2O-contents were prepared by performing Li-deficient or Li-rich vapour transport equilibration treatments on as-grown congruent LN crystals. Unclamped EO coefficients γ13 and γ33 of these samples were measured by a Mach–Zehnder interferometric method. The measurements show that in the Li-deficient regime both γ13 and γ33 increase by ∼8% as Li2O-content decreases from the congruent 48.6 mol% to the 47.0 mol% in the Li-deficient regime. The feature is desired for the EO application of the Li-deficient crystal. In the near-stoichiometric regime, both γ13 and γ33 reveal a non-monotonic dependence. As the Li2O-content increases from the 48.6 mol%, the EO coefficient decreases. Around Li2O-content 49.5 mol%, a minimum is reached. After that, the EO coefficient recovers slowly. At the stoichiometric composition, it recovers to a value close to that at the congruent point. Comparison shows that different crystal growth methods give rise to different defect structure features and hence different composition effects.

Electro-optic property of Ti^4+-doped LiNbO_3 single crystal

Electro-optic property of Ti4+-doped LiNbO3 single crystal is investigated. The electro-optic coefficients γ33 and γ13 of a series of bulk Ti4+-doped congruent LiNbO3 crystals with different Ti4+ concentrations up to 12 mol% in crystal were measured by Mach-Zehnder interferometric method and correlated with the Ti4+-doping concentration. Both clamped and unclamped coefficients were measured. The results show that both γ33 and γ13 reveal a degradation tendency with the increase of Ti4+ concentration in both cases of clamped and unclamped measurements. Nevertheless, the degradation is no more than 15% for the considered Ti4+ concentration up to 12 mol%. The little effect is explained qualitatively and comprehensibly.

Improved Φ-OTDR Sensing System for High-Precision Dynamic Strain Measurement Based on Ultra-Weak Fiber Bragg Grating Array

Phase-sensitive optical time-domain reflectometry (Φ-OTDR) has been widely used in various applications for its distributed measurement capability of dynamic disturbance along the entire length of sensing fiber. However, traditional Φ-OTDR cannot make high-precision measurement on the external disturbance-induced strain due to the randomly distributed position and reflectivity of scattering points within the optical fiber. In this paper, ultra-weak fiber Bragg grating (UWFBG) array has been proposed to generate strong and controllable reflections while providing acceptable insertion loss. Active laser frequency sweeping and unwrapping algorithms were included to set up a definite relationship between strain value and variation of interference power between neighboring reflection lights. With the assistant of UWFBG array, the capability of Φ-OTDR has been upgraded to be able to take high-precision measurement on strain. In the experiment, multipoint μϵ level dynamic strain variation has been fully captured at the end of a 5-km long sensing fiber with 2 m spatial resolution. The measured strain value was compared to the calibrated one obtained with Mach–Zehnder Interferometer method. These two values fit with each other quite well with a maximum deviation of 6.2 nϵ, which confirmed the validity and accuracy of the proposed method.

Generation and control of Bessel beams based on annular reflections

A straightforward but powerful method to generate Bessel beams with continuous control of spot size, intensity and non-diffraction zone length has been successfully developed and verified based on annular reflections using a digital micromirror device (DMD). Reflective circular ring patterns were loaded in a DMD placed in the focal point of a converging lens to generate Bessel beams with tremendous flexibility and control. A Mach–Zehnder interferometer method was applied to reconstruct the wavefront of the generated beam to prove the successful generation of the Bessel beam. This simple but powerful method has great potential in many applications, such as imaging and particle manipulation.

G0600203 加熱鉛直平板周りの自然対流温度場の簡易可視化法に関する研究

Thermo-graphical method, Mach-Zehnder interferometer method, temperature-sensitive liquid crystal and so on could be given as representative examples for the visualization method of flowing gas temperature field. In these methods, however, high setup costs and/or hard-to-use operational skills are usually required. Therefore, when it comes to obtaining an approximate gas temperature field simply and quickly, those kinds of methods are not necessarily suitable. To overcome this problem, the authors have proposed a simple visualization method by combining a mesh screen and infrared thermograph, and have examined relation between aperture ratio and apparent emissivity of the mesh screen. In this study, the proposed simple method has been applied to the natural convection around heated vertical plate, and from experimental results, its availability has been shown. To use this method as a simple practical visualization tool, however, the effects of thermal conductivity of the mesh screen, heat transfer between the heated plate surface and the mesh screen on the temperature field, and the installation effect of the mesh screen on the flow field and so on have to be clarified in a quantitative way.

Phase Microscopy Method of Micro-Nano Sized Bubbles Based on Hilbert Phase Microscopy (HPM)

Measuring shape of bubbles is very important in many industrial processes, because that its behavior in the fluid is closely related to its morphology. Phase microscopy imaging (PMI) method is one of the best useful methods in this field. In the paper, considering on PMI idea, it is put out a new method which improves an ordinary light microscope into a dual function that can do both PMI and its ordinary microscopy function. Its optical structure is designed by using Mach-Zehnder interferometer method which can be added on the platform of ordinary microscope. A glass hole (bubble) is used as a sample to do phase microscopy imaging via the improved device. The results of the experiment and theory show that the phase distribution of bubble is closely related to the shape of it, which is very useful to detect the bubble’s behavior in the flow field. Besides bubbles, the improved microscope can be also used to observe the phase body such as cells.

Analysis of reflective Mach-Zehnder interferometry for electro-optic characterization of poled polymer films in multilayer structures

We consider the Mach-Zehnder interferometer (MZI) method that specifically uses a poled organic thin film as one of the reflective mirrors in order to characterize the two independent electro-optic tensor elements r(13) and r(33). We discuss both a simple analysis based on a three-layer structure and a rigorous method including multiple reflection effects in a multilayer structure. In doing so, we find that the simple analysis of the reflective MZI method yields identical results to the reflection ellipsometric method (simple Teng-Man method), first introduced by Teng and Man as well as Shildkraut in 1990, when the ratio of r(13) to r(33) obtained from the MZI method is used in the analysis of the simple Teng-Man method. Error introduced by ignoring the multilayer nature of the sample structures in the MZI method is discussed and corrections are given for previous expressions in the literature for the simple analysis.

Effects of the multiple internal reflection and sample thickness changes on determination of electro-optic coefficient values of a polymer film

New nonlinear optical (NLO) active organic materials are appealing candidates for optoelectronic and photonic technologies. For the evaluation of new NLO polymer materials for applicability in the mentioned technologies, the most important criteria are their electro-optic (EO) coefficients. We have implemented the Mach–Zehnder interferometric (MZI) method for the determination of EO coefficients of thin organic films. Despite the fact that other multiple optical methods for the determination of thin film EO coefficients are known, the MZI method has been chosen because this particular technique has high sensitivity to phase and intensity modulations in the sample arm of an interferometer and allows one to determine independently both thin film EO coefficients, r13 and r33. In addition to the drawbacks described earlier we demonstrate that some other effects like electrostriction and multiple internal reflections in the sample have a considerable influence on light intensity at the MZI output. Taking into account these effects we have performed numerical simulations of the EO effect caused MZI output changes or modulation depth at different incidence angles using the Abeles matrix formalism. We can show that the modulated signal at the MZI output is highly dependent on the sample structure and is mainly governed by the effects mentioned above. For analysis of modulated signal components and determination of EO coefficients of a thin polymer film, a series of experiments was carried out on PMMA + DMABI 10 wt% samples.

Effects of the multiple internal reflection and sample thickness changes on determination of electro-optic coefficient values of a polymer film

New nonlinear optical (NLO) active organic materials are appealing candidates for optoelectronic and photonic technologies. For the evaluation of new NLO polymer materials for applicability in the mentioned technologies, the most important criteria are their electro-optic (EO) coefficients. We have implemented the Mach–Zehnder interferometric (MZI) method for the determination of EO coefficients of thin organic films. Despite the fact that other multiple optical methods for the determination of thin film EO coefficients are known, the MZI method has been chosen because this particular technique has high sensitivity to phase and intensity modulations in the sample arm of an interferometer and allows one to determine independently both thin film EO coefficients, r13 and r33. In addition to the drawbacks described earlier we demonstrate that some other effects like electrostriction and multiple internal reflections in the sample have a considerable influence on light intensity at the MZI output. Taking into account these effects we have performed numerical simulations of the EO effect caused MZI output changes or modulation depth at different incidence angles using the Abeles matrix formalism. We can show that the modulated signal at the MZI output is highly dependent on the sample structure and is mainly governed by the effects mentioned above. For analysis of modulated signal components and determination of EO coefficients of a thin polymer film, a series of experiments was carried out on PMMA + DMABI 10 wt% samples.

Electromechanical and electro-optic properties of xBiScO 3– yBiGaO 3–(1− x− y)PbTiO 3 single crystals

Single crystals in the xBiScO 3– yBiGaO 3–(1− x− y)PbTiO 3 (BS–BG–PT) system were grown by the high temperature solution method using Pb 3O 4 and Bi 2O 3 as the flux. The dielectric permittivity ( ε r ) at room temperature for unpoled tetragonal crystals was determined to be 500–600 with dielectric loss tangents less than 0.3%. The Curie temperature was found to be around ∼420–450°C, with a dielectric maximum, exhibiting relaxor behavior. The longitudinal piezoelectric coefficient ( d 33) was found to be ∼300 pC/N for 〈0 0 1〉 oriented tetragonal crystals with electromechanical coupling factor ( k 33) of 75%, with a shear mode, d 15∼290 pC/N and k 15∼45%, lateral mode, d 31∼−55 pC/N and k 31∼−37%. The remnant polarization ( P r) was 46 μC/cm 2 with a coercive field ( E c) of 43 kV/cm at 1 Hz and DC field of 60 kV/cm. The linear electro-optic (E-O) coefficients of poled crystals determined using an automated scanning Mach–Zehnder interferometer method at room temperature and wavelength of 632.8 nm were r 33=36 and r 13=4 pm/V, respectively.

Simultaneous measurements of complex birefringence in azo dye doped polymer films induced by linearly polarized light

A complex birefringence originating in a photoinduced alignment of azo dye (4-[ N-(2-hydroxyethyl- N-ethyl]amino--nitroazobenzene (disperse red 1)) molecules in the polymer matrix poly(methyl methacrylate) (PMMA) was determined with a Mach-Zehnder interferometric method. The complex birefringence was proportional to the intensity of the pump beam. The absolute value of the imaginary part was about half as large as the real part, although the imaginary part of the linear refractive index is negligibly small. The result suggested that the contributions of the real and imaginary parts of the complex birefringence should be observed separately even in the off-resonant case.