OPTICAL DOMAIN WALLS IN ATOMIC VAPORS

1996 ◽  
Vol 05 (03) ◽  
pp. 447-456 ◽  
Author(s):  
M. HAELTERMAN ◽  
Y. LOUIS
Keyword(s):  
Domain Wall ◽  
Nonlinear Response ◽  
Domain Walls ◽  
The Self ◽  
Laser Beams ◽  
Third Order ◽  
Atomic Vapors ◽  
Kerr Media ◽  
The Third ◽  
Optical Domain

We present a theoretical analysis of the recently discovered optical domain-wall solitons. We discuss the fundamental link which exists between diffractive spatial domain-wall solitons and the instability responsible for the self-filamentation of polarized laser beams in self-defocusing Kerr media. We show that the vector properties of the third-order nonlinear response of atomic vapors satisfy the conditions of occurrence of this instability and are therefore suited to the experimental observation of the spatial polarization domain-wall solitons.

Origin of the saturation of the third-order optical nonlinear response of one-dimensional conjugated systems

1997 ◽  
Vol 270 (5-6) ◽  
pp. 471-475 ◽  
Author(s):  
Y. Verbandt ◽  
H. Thienpont ◽  
I. Veretennicoff ◽  
P. Geerlings ◽  
G.L.J.A. Rikken
Keyword(s):  
Nonlinear Response ◽  
Third Order ◽  
One Dimensional ◽  
Conjugated Systems ◽  
The Third

SIZE DEPENDENT SWITCHING FROM REVERSE SATURABLE TO SATURABLE ABSORPTION IN CARBOXYLATE-MODIFIED MICROSPHERES

2011 ◽  
Vol 20 (02) ◽  
pp. 137-143
Author(s):  
MANU VAISHAKH ◽  
S. MATHEW ◽  
V. P. N. NAMPOORI
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Nonlinear Response ◽  
Second Harmonic ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Third Order ◽  
Size Dependent ◽  
The Third ◽  
532 Nm

The third order nonlinear optical properties of two different sized carboxylate-modified microspheres are investigated at different pump powers. The nonlinear absorption (NLA) is measured at 532 nm using 10 Hz, 7 ns pulses from the second harmonic generated from a Q-switched Nd -YAG laser in an open aperture Z-scan setup. The nonlinear response is size-dependent, and switching from reverse saturable absorption (RSA) to saturable absorption (SA) is observed as the size increases.

Mechanisms of the Nonlinear Optical Response in Tetraras(Cumylphenoxy)Phthalocyanines

1992 ◽  
Vol 247 ◽  
Author(s):  
Steven R. Flom ◽  
James S. Shirk ◽  
J. R. Lindle ◽  
F. J. Bartoli ◽  
Zakya H. Kafafi ◽  
...  
Keyword(s):  
Thin Film ◽  
Figure Of Merit ◽  
Nonlinear Optical ◽  
Nonlinear Response ◽  
Physical State ◽  
Third Order ◽  
Metal Free ◽  
The Third ◽  
Nlo Response ◽  
Near Resonance

ABSTRACTThe third order nonlinear optical (NLO) response of metal free tetrakis(cumylphenoxy)-phthalocyanine, (H2Pc(CP)4) was investigated at 597 nm, near resonance with the strong Q band. The second hyperpolarizability, γ, and the figure of merit, χ(3)/α, measured with a 1.2 ps pulse. was approximately independent of concentration between a 4.6×10−4 M solution and a neat thin film. The decay of the nonlinear response, however, depended substantially on the concentration and physical state of the material.

Ultrafast dynamics of the third-order nonlinear response in a two-dimensional InP-based photonic crystal

2004 ◽  
Vol 85 (11) ◽  
pp. 1880-1882 ◽  
Author(s):  
F. Raineri ◽  
Crina Cojocaru ◽  
P. Monnier ◽  
A. Levenson ◽  
R. Raj ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Nonlinear Response ◽  
Ultrafast Dynamics ◽  
Two Dimensional ◽  
Third Order ◽  
The Third

scholarly journals Self-Preservation of Turbulence Statistics in the Wall-Wake Flow of a Bed-Mounted Horizontal Pipe

Fluids ◽  
2021 ◽  
Vol 6 (12) ◽  
pp. 453
Author(s):  
Kalpana Devi ◽  
Prashanth Reddy Hanmaiahgari ◽  
Ram Balachandar ◽  
Jaan H. Pu
Keyword(s):  
Three Dimensional ◽  
Streamwise Velocity ◽  
The Self ◽  
Wake Flow ◽  
Wake Region ◽  
Third Order ◽  
Mean Velocity ◽  
Horizontal Pipe ◽  
The Third ◽  
Normal Distance

This research article analyzed the self-preserving behaviour of wall-wake region of a circular pipe mounted horizontally over a flat rigid sand bed in a shallow flow in terms of mean velocity, RSS, and turbulence intensities. The study aims to investigate self-preservation using appropriate length and velocity scales.in addition to that wall-normal distributions of the third-order correlations along the streamwise direction in the wake region are analyzed. An ADV probe was used to record the three-dimensional instantaneous velocities for four different hydraulic and physical conditions corresponding to four cylinder Reynolds numbers. The results revealed that the streamwise velocity deficits, RSS deficits, and turbulence intensities deficits distributions displayed good collapse on a narrow band when they were non-dimensionalized by their respective maximum deficits. The wall-normal distance was non-dimensionalized by the half velocity profile width for velocity distributions, while the half RSS profile width was used in the case of the RSS deficits and turbulence intensities deficits distributions. The results indicate the self-preserving nature of streamwise velocity, RSS, and turbulence intensities in the wall-wake region of the pipe. The third-order correlations distributions indicate that sweep is the dominant bursting event in the near-bed zone. At the same time, ejection is the dominant bursting event in the region above the cylinder height.

scholarly journals Hydrodynamic nonlinear response of interacting integrable systems

2021 ◽  
Vol 118 (37) ◽  
pp. e2106945118
Author(s):  
Michele Fava ◽  
Sounak Biswas ◽  
Sarang Gopalakrishnan ◽  
Romain Vasseur ◽  
S. A. Parameswaran
Keyword(s):  
Integrable Systems ◽  
Finite Temperature ◽  
Spin Chain ◽  
Numerical Evaluation ◽  
Nonlinear Response ◽  
Hydrodynamic Limit ◽  
Arbitrary Order ◽  
Third Order ◽  
The Third ◽  
Spatially Resolved

We develop a formalism for computing the nonlinear response of interacting integrable systems. Our results are asymptotically exact in the hydrodynamic limit where perturbing fields vary sufficiently slowly in space and time. We show that spatially resolved nonlinear response distinguishes interacting integrable systems from noninteracting ones, exemplifying this for the Lieb–Liniger gas. We give a prescription for computing finite-temperature Drude weights of arbitrary order, which is in excellent agreement with numerical evaluation of the third-order response of the XXZ spin chain. We identify intrinsically nonperturbative regimes of the nonlinear response of integrable systems.

The direct determination of magnetic domain wall profiles using a split detector STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 466-467
Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Domain Wall ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Photographic Plate ◽  
Magnetic Domain ◽  
Direct Determination ◽  
Quantitative Information ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

The need of electron microscopy in the study of domains and domain walls in ferroelectrics

1994 ◽  
Vol 52 ◽  
pp. 550-551
Author(s):  
Wenwu Cao
Keyword(s):  
Domain Wall ◽  
Domain Walls ◽  
High Mobility ◽  
Continuum Theory ◽  
Polarization Vector ◽  
Ferroelectric Materials ◽  
Dielectric Constants ◽  
Nonlocal Coupling ◽  
Cubic Symmetry ◽  
Gradient Energy

Domain structures play a key role in determining the physical properties of ferroelectric materials. The formation of these ferroelectric domains and domain walls are determined by the intrinsic nonlinearity and the nonlocal coupling of the polarization. Analogous to soliton excitations, domain walls can have high mobility when the domain wall energy is high. The domain wall can be describes by a continuum theory owning to the long range nature of the dipole-dipole interactions in ferroelectrics. The simplest form for the Landau energy is the so called ϕ model which can be used to describe a second order phase transition from a cubic prototype,where Pi (i =1, 2, 3) are the components of polarization vector, α's are the linear and nonlinear dielectric constants. In order to take into account the nonlocal coupling, a gradient energy should be included, for cubic symmetry the gradient energy is given by,

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