23 research outputs found
Electromagnetic diffraction efficiencies for plane reflection diffraction gratings
Results are presented of research activities on holographic grating research. A large portion of this work was performed using rigorous vector diffraction theory, therefore, the necessary theory has been included in this report. The diffraction efficiency studies were continued using programs based on a rigorous theory. The simultaneous occurrence of high diffraction efficiencies and the phenomenon of double Wood's anomalies is demonstrated along with a graphic method for determining the necessary grating parameters. Also, an analytical solution for a grating profile that is perfectly blazed is obtained. The performance of the perfectly blazed grating profile is shown to be significantly better than grating profiles previously studied. Finally, a proposed method is described for the analysis of coarse echelle gratings using rigorous vector diffraction that is currently being developed
Electromagnetic diffraction efficiencies for plane reflection diffraction gratings
The theory and computer programs, based on electromagnetic theory, for the analysis and design of echelle gratings were developed. The gratings are designed for instruments that operate in the ultraviolet portion of the spectrum. The theory was developed so that the resulting computer programs will be able to analyze deep (up to 30 wavelengths) gratings by including as many as 100 real or homogeneous diffraction orders. The program calculates the complex amplitude coefficient for each of the diffracted orders. A check on the numerical method used to solve the integral equations is provided by a conservation of energy calculation
Infrared Astronomical Satellite (IRAS) analysis of the transmittance of off-axis energy due to scattering and diffraction
Stray light transmittance is analyzed. Mathematical models are evaluated. The results of scatter and diffraction are considered separately, and the combined transmittance values evaluated
Planck scale still safe from stellar images
The recent paper of Lieu and Hillman [1] that a possible, (birefringence
like) phase difference ambiguity coming from Planck effects would alter stellar
images of distant sources is questioned. Instead for {\em division of
wavefront} interference and diffraction phenomena, initial (lateral) coherence
is developed simply by propagation of rays (cf. van Cittert-Zernike theorem).
This case is strongly immune to quantum gravity influences that could tend to
reduce phase coherence. The phase ambiguity, if actually present, could reduce
any underlying polarization of the light rays.Comment: final version for CQ
Space-Time Approach to Scattering from Many Body Systems
We present scattering from many body systems in a new light. In place of the
usual van Hove treatment, (applicable to a wide range of scattering processes
using both photons and massive particles) based on plane waves, we calculate
the scattering amplitude as a space-time integral over the scattering sample
for an incident wave characterized by its correlation function which results
from the shaping of the wave field by the apparatus. Instrument resolution
effects - seen as due to the loss of correlation caused by the path differences
in the different arms of the instrument are automatically included and analytic
forms of the resolution function for different instruments are obtained. The
intersection of the moving correlation volumes (those regions where the
correlation functions are significant) associated with the different elements
of the apparatus determines the maximum correlation lengths (times) that can be
observed in a sample, and hence, the momentum (energy) resolution of the
measurement. This geometrical picture of moving correlation volumes derived by
our technique shows how the interaction of the scatterer with the wave field
shaped by the apparatus proceeds in space and time. Matching of the correlation
volumes so as to maximize the intersection region yields a transparent,
graphical method of instrument design. PACS: 03.65.Nk, 3.80 +r, 03.75, 61.12.BComment: Latex document with 6 fig
Recommended from our members
POLARIZATION OPERATOR FOR CHOLESTERIC LIQUID CRYSTALS
QC 351 A7 no. 63A Jones matrix operator is derived for a liquid crystal in the cholesteric phase for light incident normal to the molecular planes. We also derive a similar operator to include the effect of absorption. It is seen that, in general, the right and left circular polarizations are not the natural eigenstates.This title from the Optical Sciences Technical Reports collection is made available by the College of Optical Sciences and the University Libraries, The University of Arizona. If you have questions about titles in this collection, please contact [email protected]