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Deuelopment of a Computer Program for the Determination of Opticrl Constants of Radiation Damaged Optical Elements Using Classical Oscillator Fit to Reflectance and/or Trrnsmittrnce Data

Published online by Cambridge University Press:  25 February 2011

Miftahur Rahman
Affiliation:
Department of Physics, University of Massachusetts-Lowell, Lowell, MA
C. Yang
Affiliation:
Department of Physics, University of Massachusetts-Lowell, Lowell, MA
K. S. Chiu
Affiliation:
Department of Physics, University of Massachusetts-Lowell, Lowell, MA
A. S. Karakashian
Affiliation:
Department of Physics, University of Massachusetts-Lowell, Lowell, MA
C. Karp
Affiliation:
Barr Associates, MA.
T. Mooney
Affiliation:
Barr Associates, MA.
G. Al-Jumaily
Affiliation:
Barr Associates, MA.
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A computer program is developed using the classical oscillator model of Hans W. Verleur [1] to study the transmittance and reflectance spectra of pre- and post radiation damaged optical components such as color glass filters, multilayer bandpass filters and band reject filters irradiated by one megárad gamma radiation from a 60Co source. In the classical oscillator model, the complex dielectric constant ε(ω) is represented as the sum of classical oscillators with oscillator strength Si, resonance frequency ωi, linewidth Γi and high frequency dielectric constant ε∞ which are the adjustable parameters to fit the experimental transmittance and reflectance data over a limited range of frequency. The parameters have physical significance in the lattice vibrational region. In the spectral regions corresponding to electronic transitions, the spectra can be fitted accurately with no physical meaning associated with the parameters. The present work has concentrated on the calculations of the optical constants n and k of the radiation damaged optical components to determine the effects of 60Co gamma radiation on the optical constants of both films and substrates in these components.

Type
Research Article
Copyright
Copyright © Materials Research Society 1992

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References

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