Incorporating optical bistability into a magnetically bistable system: a photochromic redox isomeric complex

Based upon the combination of the pseudo-arclength continuation method and the Poincaré map defined on a variable return plane, systems of equations are constructed that trace a Takens-Bogdanov bifurcation, a cusp, an isola formation/perturbed bifurcation point and a degenerate period-doubling/secondary Hopf bifurcation of periodic solutions of autonomous ordinary differential equations. The implementation of these ideas into a collection of FORTRAN codes and its application to a five-dimensional system describing an optical bistable system lead to the detection of interesting codimension-3 bifurcations away from the stationary behavior. A winged cusp, a swallow tail, a degenerate hysteresis point, an isola formation point for a codimension-1 loop and two kinds of degenerate Takens-Bogdanov bifurcations of periodic solutions are presented. Finally, based upon the computation of the stability coefficient “a”, attractive tori are found in a systematic way and briefly discussed.

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External Switching Dynamics of Optical Bistability System Simulation

Iraqi Journal of Science ◽

10.24996/ijs.2020.61.5.11 ◽

2020 ◽

pp. 1027-1031

Author(s):

Ali Hassan Khidhir

Keyword(s):

Optical Bistability ◽

System Simulation ◽

Input Pulse ◽

External Source ◽

External Input ◽

Bistable System ◽

Switching Dynamics ◽

Mirror Reflectivity ◽

Fabry Perot ◽

Set Up

In this work, the external switching dynamics of a Fabry-Perot etalon are studied via optical bistability system simulation. The simulated set-up of this investigation consists of two laser beams; the first beam is continuous (CW) which is considered as a biasing beam and capable of holding the bistable system for a certain range, which we are interested in, from a point that is very close self-switching to a point where the switching is unachievable. The second beam is modulated by passing the first beam through an acousto-optic modulator (AOM) to produce pulses with a minimum rise time and is used as an external source (coherent switching). In this work, we obtained the optical bistable loops by applying absorption coefficient (α) = 20cm-1, e sample etalon thickness (D) = 110μm, forward mirror reflectivity (Rf) = 0.6, and backward mirror reflectivity (Rb) = 0.95. The steady state characteristic of an initial detuning of the cavity (φ0) = 0.8 was studied at the conditions of no external input pulse intensity (M(t) = 0) and switching that takes place at Is(ON)= 0.57mW and Is(OFF) = 0.4mW.

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FLUCTUATION-INDUCED SYMMETRY BREAKING IN A BISTABLE SYSTEM: A GENERIC MECHANISM OF SELECTION BETWEEN COMPETING OPTIONS

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127404010667 ◽

2004 ◽

Vol 14 (07) ◽

pp. 2399-2405 ◽

Cited By ~ 3

Author(s):

S. C. NICOLIS

Keyword(s):

Symmetry Breaking ◽

White Noise ◽

Evolution Equations ◽

System Modeling ◽

Internal Variability ◽

The State ◽

Bistable System ◽

System A ◽

Additive White Noise

A two-variable bistable system modeling the selection between competing options is considered in the presence of additive white noise, representing environmental or internal variability. It is shown that when the strengths of the noises acting on the evolution equations of the two variables are different a symmetry-breaking process takes place, whereby the state in which the excess variable is perturbed by the strongest noise becomes predominant.

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Analysis of bistability at the coupling between waveguide and whispering gallery modes of a nonlinear hemicylinder

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac49b8 ◽

2022 ◽

Author(s):

Henrik Parsamyan ◽

Khachik Sahakyan ◽

Khachatur Nerkararyan

Keyword(s):

Parallel Plate ◽

Optical Bistability ◽

Switching Time ◽

Metal Layer ◽

Whispering Gallery Modes ◽

Optical Effect ◽

Whispering Gallery ◽

System A ◽

Parallel Plate Waveguide ◽

Theoretical And Numerical Analysis

Abstract The optical bistability caused by the coupling between modes of the parallel-plate waveguide and a nonlinear hemicylindrical crystal is studied using theoretical and numerical analysis. In such a system a waveguide channel is parallelly coupled to whispering gallery modes of a hemicylindrical microresonator ensuring bistable behaviour at input intensities of the order of a few MW/cm2. The characteristic minimum switching time of the system (around 30 ps) can be controlled by varying the thickness of the metal layer which couples the waveguide and whispering gallery modes. This is conditioned by the change of the quality Q-factor, as well as the coupling coefficient of the resonator. The main advantages of the system are fabrication simplicity, small sizes of the order of 3 µm and the possibility of adjusting the processes by making use of the electro-optical effect.

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New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006427x ◽

1971 ◽

Vol 29 ◽

pp. 44-45

Author(s):

R. C. Moretz ◽

G. G. Hausner ◽

D. F. Parsons

Keyword(s):

Electron Microscopy ◽

Water Vapor ◽

Electron Diffraction ◽

Water Vapor Pressure ◽

Biological Materials ◽

Thin Membrane ◽

Reliable System ◽

System A ◽

Water Films ◽

Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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High-resolution electron microscopy of Cu2O surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143584 ◽

1986 ◽

Vol 44 ◽

pp. 396-397

Author(s):

V. Castano ◽

W. Krakow

Keyword(s):

High Resolution ◽

Natural Extension ◽

High Resolution Electron Microscopy ◽

Point Of View ◽

Initial Oxidation ◽

System A ◽

Resolution Electron ◽

Surface Reconstructions ◽

Atomic Surface ◽

Au Thin Films

In non-UHV microscope environments atomic surface structure has been observed for flat-on for various orientations of Au thin films and edge-on for columns of atoms in small particles. The problem of oxidation of surfaces has only recently been reported from the point of view of high resolution microscopy revealing surface reconstructions for the Ag2O system. A natural extension of these initial oxidation studies is to explore other materials areas which are technologically more significant such as that of Cu2O, which will now be described.

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Twin boundary structure of a Y-Ba-Cu-O superconductor

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152811 ◽

1989 ◽

Vol 47 ◽

pp. 168-169

Author(s):

Yimei Zhu ◽

Masaki Suenaga ◽

R. L. Sabatini ◽

Youwen Xu

Keyword(s):

Twin Boundary ◽

Fine Particles ◽

Imaging Techniques ◽

Fine Powder ◽

Orthorhombic Phase ◽

Boundary Structure ◽

Crystallographic Axis ◽

System A ◽

High Resolution Structure ◽

Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

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Speech Therapy Services in a Large School System: A Six-Year Overview

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.0704.207 ◽

1976 ◽

Vol 7 (4) ◽

pp. 207-219 ◽

Cited By ~ 3

Author(s):

Constance P. DesRoches

Keyword(s):

School System ◽

Speech Therapy ◽

Factors Affecting ◽

Case Load ◽

Number Of Children ◽

School Population ◽

System A ◽

Therapy Services ◽

And Shifts ◽

Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

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