Laser-induced modification of the optical properties of transparent materials

Author(s):  
David Ashkenasi ◽  
Kazem J. Ghaleh ◽  
Hans-Juergen Hoffmann
2013 ◽  
Vol 811 ◽  
pp. 353-357
Author(s):  
Kuen Tea Park ◽  
Moon G. Lee ◽  
Dae Sik Jeong ◽  
Dong Kwon Kim ◽  
Moo Joong Kim ◽  
...  

Recently, study of transparent materials, such as thin film form, have an important field for the development of advanced electronic devices. Therefore, the need for the precision thermal property measurement techniques of transparent thin film materials becomes increasing according to the development of these material. The ideal methods for optically measurements of these properties are noncontact method. However, optically measurements are often difficult due to the transparency. So, transparent materials have not enough temperature gradient in the air layer above thin films. To solve this problem, we used the collinear deflection method which is one of the photothermal deflection methods. In the measurement process, both of the pump beam and probe beam are irradiated vertically on the transparent sample. And the probe beam is deflected by refractive index variation of samples due to the temperature gradient inside samples.The purpose of this study is to analyze the effect of thermal and optical properties analytically on the collinear deflection method for variable materials.


2003 ◽  
Author(s):  
David Ashkenasi ◽  
Hans-Juergen Hoffmann ◽  
Dieter Krause ◽  
Gerhard J. Mueller

1943 ◽  
Vol 47 (392) ◽  
pp. 263-272 ◽  
Author(s):  
R. E. Arthur

Many problems arise in stress analysis which are not reasonably susceptible to mathematical treatment. Recourse may then be had to experimental methods. One of the most useful of these is the photoelastic method. This method is based upon the fact that transparent materials when stressed undergo changes in their optical properties which can be measured and related to the applied stress.


Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.


Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).


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):  
R. B. Queenan ◽  
P. K. Davies

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.


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