A microscopic bright-field image technique for the measurement of averaged index profiles of quasi-axially symmetric large-mode-area microstructured fibers

Due to its microstructure, photonic crystal fibers present wavelength regions with polarization-dependent loss, an aspect not observed in conventional fibers. We include this fact in their polarization characterization. In this research, the use of polarimetric methods to two different types of large-mode-area microstructured fibers has shown that both samples exhibited elliptical birefringence with residual torsion. We present the modifications required to perform the evaluation and justify its theoretical bases.

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The effect of periodicity on the defect modes of large mode area microstructured fibers

Optics Express ◽

10.1364/oe.16.018631 ◽

2008 ◽

Vol 16 (23) ◽

pp. 18631 ◽

Cited By ~ 8

Author(s):

Joanne C. Flanagan ◽

R. Amezcua ◽

F. Poletti ◽

J. R. Hayes ◽

N. G. R. Broderick ◽

...

Keyword(s):

Defect Modes ◽

Microstructured Fibers ◽

Large Mode Area ◽

Mode Area

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Arsenic segregation in polysilicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074604 ◽

1983 ◽

Vol 41 ◽

pp. 154-155 ◽

Cited By ~ 1

Author(s):

P.E. Batson ◽

C.R.M. Grovenor ◽

D.A. Smith ◽

C. Wong

Keyword(s):

Incident Beam ◽

Silicon Wafers ◽

Chemical Polishing ◽

Bright Field Image ◽

Beam Size ◽

Stem Analysis ◽

Bright Field ◽

Twin Boundaries ◽

X Ray ◽

Line Scan

In this work As doped polysilicon was deposited onto (100) silicon wafers by APCVD at 660°C from a silane-arsine mixture, followed by a ten minute anneal at 1000°C, and in one case a further ten minute anneal at 700°C. Specimens for TEM and STEM analysis were prepared by chemical polishing. The microstructure, which is unchanged by the final 700°C anneal,is shown in Figure 1. It consists of numerous randomly oriented grains many of which contain twins.X-ray analysis was carried out in a VG HB5 STEM. As K α x-ray counts were collected from STEM scans across grain and twin boundaries, Figures 2-4. The incident beam size was about 1.5nm in diameter, and each of the 20 channels in the plots was sampled from a 1.6nm length of the approximately 30nm line scan across the boundary. The bright field image profile along the scanned line was monitored during the analysis to allow correlation between the image and the x-ray signal.

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Lattice Imaging of Twin, Lath and α/Martensite Boundaries in Duplex Low Carbon Steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078195 ◽

1977 ◽

Vol 35 ◽

pp. 118-119

Author(s):

J. Y. Koo ◽

G. Thomas

Keyword(s):

High Resolution Electron Microscopy ◽

Ferrite Matrix ◽

Carbon Steels ◽

Bright Field Image ◽

Low Carbon ◽

Lattice Imaging ◽

Bright Field ◽

Lattice Image ◽

New Information ◽

Resolution Electron

High resolution electron microscopy has been shown to give new information on defects(1) and phase transformations in solids (2,3). In a continuing program of lattice fringe imaging of alloys, we have applied this technique to the martensitic transformation in steels in order to characterize the atomic environments near twin, lath and αmartensite boundaries. This paper describes current progress in this program.Figures A and B show lattice image and conventional bright field image of the same area of a duplex Fe/2Si/0.1C steel described elsewhere(4). The microstructure consists of internally twinned martensite (M) embedded in a ferrite matrix (F). Use of the 2-beam tilted illumination technique incorporating a twin reflection produced {110} fringes across the microtwins.

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Correlation analysis of radiation damage

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108210 ◽

1978 ◽

Vol 36 (1) ◽

pp. 214-215

Author(s):

R. Hegerl ◽

A. Feltynowski ◽

B. Grill

Keyword(s):

Electron Microscopy ◽

Independent Random Variables ◽

Optical Parameters ◽

Bright Field Image ◽

Bright Field ◽

Expectation Value ◽

All Optical ◽

Image Element ◽

Stochastic Series ◽

The Common

Till now correlation functions have been used in electron microscopy for two purposes: a) to find the common origin of two micrographs representing the same object, b) to check the optical parameters e. g. the focus. There is a third possibility of application, if all optical parameters are constant during a series of exposures. In this case all differences between the micrographs can only be caused by different noise distributions and by modifications of the object induced by radiation.Because of the electron noise, a discrete bright field image can be considered as a stochastic series Pm,where i denotes the number of the image and m (m = 1,.., M) the image element. Assuming a stable object, the expectation value of Pm would be Ηm for all images. The electron noise can be introduced by addition of stationary, mutual independent random variables nm with zero expectation and the variance. It is possible to treat the modifications of the object as a noise, too.

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