scholarly journals Oblique propagation of the quantum states ‎of s(p)-polarized light through non-‎Hermitian multilayered structures

2022 ◽  
Author(s):  
Elnaz Pilehvar ◽  
Ehsan Amooghorban ◽  
Mohammad Moravvej-Farshi
2014 ◽  
Vol 215 ◽  
pp. 331-336
Author(s):  
Ivan D. Lobov ◽  
Margarita M. Kirillova ◽  
Lazar N. Romashev ◽  
Mikhail A. Milyaev ◽  
Vladimir V. Ustinov

The magnetorefractive effect (MRE) has been measured in the infrared spectral region of 1.2-28 μm in MBE-grown Fe/Cr superlattices with variable Fe and Cr layers thicknesses inp-polarized light. The magnetic and magnetooptical properties have been studied as well. From the MRE spectra modeling in the framework of magnetoreflection theory for multilayered structures, the parameters of interfacial spin dependent scattering of conductivity electrons have been defined for different types of exchange coupling between adjacent Fe layers. The dependence of interfacial scattering parameters on Fe and Cr layer thickness is discussed.


Author(s):  
L. D. Ackerman ◽  
S. H. Y. Wei

Mature human dental enamel has presented investigators with several difficulties in ultramicrotomy of specimens for electron microscopy due to its high degree of mineralization. This study explores the possibility of combining ion-milling and high voltage electron microscopy as a means of circumventing the problems of ultramicrotomy.A longitudinal section of an extracted human third molar was ground to a thickness of about 30 um and polarized light micrographs were taken. The specimen was attached to a single hole grid and thinned by argon-ion bombardment at 15° incidence while rotating at 15 rpm. The beam current in each of two guns was 50 μA with an accelerating voltage of 4 kV. A 20 nm carbon coating was evaporated onto the specimen to prevent an electron charge from building up during electron microscopy.


Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.


Author(s):  
Marcos F. Maestre

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.


Author(s):  
Rudolf Oldenbourg

The recent renaissance of the light microsope is fueled in part by technological advances in components on the periphery of the microscope, such as the laser as illumination source, electronic image recording (video), computer assisted image analysis and the biochemistry of fluorescent dyes for labeling specimens. After great progress in these peripheral parts, it seems timely to examine the optics itself and ask how progress in the periphery facilitates the use of new optical components and of new optical designs inside the microscope. Some results of this fruitful reflection are presented in this symposium.We have considered the polarized light microscope, and developed a design that replaces the traditional compensator, typically a birefringent crystal plate, with a precision universal compensator made of two liquid crystal variable retarders. A video camera and digital image processing system provide fast measurements of specimen anisotropy (retardance magnitude and azimuth) at ALL POINTS of the image forming the field of view. The images document fine structural and molecular organization within a thin optical section of the specimen.


Author(s):  
W. E. Rigsby ◽  
D. M. Hinton ◽  
V. J. Hurst ◽  
P. C. McCaskey

Crystalline intracellular inclusions are rarely seen in mammalian tissues and are often difficult to positively identify. Lymph node and liver tissue samples were obtained from two cows which had been rejected at the slaughter house due to the abnormal appearance of these organs in the animals. The samples were fixed in formaldehyde and some of the fixed material was embedded in paraffin. Examination of the paraffin sections with polarized light microscopy revealed the presence of numerous crystals in both hepatic and lymph tissue sections. Tissue sections were then deparaffinized in xylene, mounted, carbon coated, and examined in a Phillips 505T SEM equipped with a Tracor Northern X-ray Energy Dispersive Spectroscopy (EDS) system. Crystals were obscured by cellular components and membranes so that EDS spectra were only obtainable from whole cells. Tissue samples which had been fixed but not paraffin-embedded were dehydrated, embedded in Spurrs plastic, and sectioned.


Author(s):  
W.S. Putnam ◽  
C. Viney

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.


Author(s):  
Rudolf Oldenbourg

The polarized light microscope has the unique potential to measure submicroscopic molecular arrangements dynamically and non-destructively in living cells and other specimens. With the traditional pol-scope, however, single images display only those anisotropic structures that have a limited range of orientations with respect to the polarization axes of the microscope. Furthermore, rapid measurements are restricted to a single image point or single area that exhibits uniform birefringence or other form of optical anisotropy, while measurements comparing several image points take an inordinately long time.We are developing a new kind of polarized light microscope which combines speed and high resolution in its measurement of the specimen anisotropy, irrespective of its orientation. The design of the new pol-scope is based on the traditional polarized light microscope with two essential modifications: circular polarizers replace linear polarizers and two electro-optical modulators replace the traditional compensator. A video camera and computer assisted image analysis provide measurements of specimen anisotropy in rapid succession for all points of the image comprising the field of view.


Author(s):  
Walter C. McCrone

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).


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