New developments in photochromic materials showing large change in the refractive index

2008 ◽  
Author(s):  
Andrea Bianco ◽  
Chiara Bertarelli ◽  
Giovanni Dassa ◽  
Giorgio Toso ◽  
Marta Lanata ◽  
...  
Keyword(s):  
Refractive Index ◽  
Large Change ◽  
New Developments ◽  
Photochromic Materials

THIN-LAYER HOLOGRAPHIC PHOTOPOLYMER MATERIALS WITH A LARGE CHANGE IN THE REFRACTIVE INDEX

2021 ◽  
Vol 57 (6) ◽  
pp. 29-37
Author(s):  
D. I. Derevianko ◽  
E. F. Pen ◽  
V. V. Shelkovnikov ◽  
S. I. Aliev
Keyword(s):  
Refractive Index ◽  
Thin Layer ◽  
Large Change

The Effect of Refractive Index of the Medium on the Position of the Camera Lens in Schlieren Optics

1973 ◽  
Vol 51 (20) ◽  
pp. 3309-3312 ◽  
Author(s):  
L. Ivan Epstein ◽  
Percival Nixon ◽  
Alfred J. Richard
Keyword(s):  
Refractive Index ◽  
Linear Relation ◽  
Large Change ◽  
Optic Axis ◽  
Liquid Column ◽  
Camera Lens ◽  
Component Systems ◽  
Schlieren Optics

A linear relation has been established between the plane of focus for schlieren optics in the ultracentrifuge cell along the optic axis, and the refractive index of the liquid contained in the cell. Such a relation shows that there occurs a defocussing effect when a large change in refractive index is generated in the liquid column during centrifugation of multi-component systems.

New developments in photochromic materials for volume phase holographic gratings

2006 ◽  
Author(s):  
Andrea Bianco ◽  
Chiara Bertarelli ◽  
Paolo Conconi ◽  
Emilio Molinari ◽  
Clara Quaglia ◽  
...  
Keyword(s):  
New Developments ◽  
Holographic Gratings ◽  
Volume Phase ◽  
Photochromic Materials

Technique for Measuring Refractive Index Changes in Photochromic Materials

1975 ◽  
Vol 14 (5) ◽  
pp. 1100 ◽  
Author(s):  
W. J. Tomlinson ◽  
G. D. Aumiller
Keyword(s):  
Refractive Index ◽  
Index Changes ◽  
Photochromic Materials

scholarly journals Holography with Photochromic Diarylethenes

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2810 ◽  
Author(s):  
Luca Oggioni ◽  
Giorgio Pariani ◽  
Frédéric Zamkotsian ◽  
Chiara Bertarelli ◽  
Andrea Bianco
Keyword(s):  
Refractive Index ◽  
Chemical Process ◽  
High Efficiency ◽  
Light Exposure ◽  
Complex Refractive Index ◽  
High Fidelity ◽  
System A ◽  
Reconfigurable Platform ◽  
Photochromic Materials ◽  
Phase Holograms

Photochromic materials are attractive for the development of holograms for different reasons: they show a modulation of the complex refractive index, meaning they are suitable for both amplitude and phase holograms; they are self-developing materials, which do not require any chemical process after the light exposure to obtain the final hologram; the holograms are rewritable, making the system a convenient reconfigurable platform for these types of diffractive elements. In this paper, we will show the features of photochromic materials, in particular diarylethenes in terms of the modulation of a transparency and refractive index, which are mandatory for their use in holography. Moreover, we report on the strategies used to write binary and grayscale holograms and their achieved results. The outcomes are general, and they can be further applied to other classes of photochromic materials in order to optimize the system for achieving high efficiency and high fidelity holograms.

Wavelength Dependence of the Photorefractive and Photodiffractive Properties of Holographic Thin Films Based on Bacteriorhodopsin

1990 ◽  
Vol 218 ◽  
Author(s):  
Robert R. Birge ◽  
K. Can Izgi ◽  
Jeffrey A. Stuart ◽  
Jack R. Tallent
Keyword(s):  
Refractive Index ◽  
Large Change ◽  
Wave Theory ◽  
Wavelength Dependence ◽  
Solute Concentration ◽  
Maximum Efficiency ◽  
Optical Absorption Spectroscopy ◽  
Phase Component ◽  
Absorption Component ◽  
Negative Band

AbstractThe photorefractive and photodiffractive properties of a 2 × 10−3 M, 30μim thin film of bacteriorhodopsin at - 40°C are analyzed by using optical absorption spectroscopy, the Kramers- Kronig transformation and coupled wave theory. Conversion of M to bR generates a dispersion in the refractive index that has a broad negative band from 450 to 540 nm [Δn500nm - -0.0016] and a broad positive band from 590 to 700 nm [Δn605nm - 0.0016]. The large change in refractive index for moderate solute concentration is due to the formation of the protonated Schiff base chromophore in bR which generates a large red shift in the absorption spectrum as well as a large increase in oscillator strength. The integrated diffraction efficiency from 300 - 800nm is dominated by refractive index contributions (ηphase) which are maximum in regions of minimal bR and M absorption. The maximum in the refractive (phase) component occurs at 451 nm (ηphase - 9.7%) whereas the maximum in the absorption component occurs at 575 nm (ηabs - 2.2%). The maximum efficiency of diffraction is observed at ∼440 nm (ηtotal - 10.7%). Adequate diffractive performance for most applications is predicted for write wavelengths in the regions 380 - 420 & 500 - 650 nm and for read wavelengths from 380 to 740 nm.

3D Core Thermal Hydraulics With the PORFLO Code: Turbulence Modeling and Porous Medium With Porosity Steps

2014 ◽  
Author(s):  
Mikko Ilvonen ◽  
Ville Hovi ◽  
Veikko Taivassalo
Keyword(s):  
Porous Medium ◽  
Turbulence Modeling ◽  
Large Change ◽  
Two Phase ◽  
New Developments ◽  
Flow Solver ◽  
Macroscopic Models ◽  
Dynamics Simulations ◽  
Coupled Solution ◽  
Drag Term

VTT is developing a 3D two-phase flow solver code called PORFLO with the objective of enabling coupled reactor dynamics simulations through a parallel computation and porous medium description of complex geometries. The current features include unstructured mesh usage, 6-equation flow solution, k-ε turbulence modeling and MPI parallelization. The present applications are fuel bundles and cores of VVER and EPR, with a steam generator and core debris bed having been simulated previously. In this work, the main new developments are improved turbulence modeling, improved interpolation of face velocities in porous medium, and new improved modeling of EPR plant. The recent work examines porous medium based macroscopic models for turbulence quantities in the fuel assembly sub-channels. A few modifications in the standard k-ε turbulence model were tested against experimental data from the AGATE, MATiS-H and IVO VVER LDA measurements. In the coupled solution of pressure and velocities, problems were encountered at locations with a large change in the porosity. In the latest development, the pressure weighted momentum interpolation of face velocities was modified to explicitly account for the interphase drag term, in a manner similar to the Coupled Phasic Exchange Algorithm. In this work, the improved two-phase solver was tested in single-phase cases.

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