Rigorous electromagnetic calculations in radiometry
Author(s)
Gogornas, Alexandros
Type
Thesis
Abstract
Until recently, accurate estimates in radiometry using geometrical optics were justified
because of the use of optical frequencies and large apertures. Nevertheless
in modern radiometry, due to the increased interest in longer wavelengths and the
improvement of experimental accuracy, geometrical optics cannot provide accurate
enough estimates for experimental purposes. Initially the accuracy was improved
by using the Fresnel approximation for the calculation of physical flux. Obviously
this approach includes all the common approximations of scalar diffraction theories,
namely scalar field, infinitely thin aperture and perfectly absorbing screen. Therefore,
a more accurate model is introduced that accounts for the vector nature of
light, finite thickness for the aperture and infinite conducting screen which is a
good approximation because of the use of longer wavelengths. The application of
this model, as well as abandoning the single wavelength approximation, results in
deviations from scalar theory of 1% for a typical radiometric configuration.
because of the use of optical frequencies and large apertures. Nevertheless
in modern radiometry, due to the increased interest in longer wavelengths and the
improvement of experimental accuracy, geometrical optics cannot provide accurate
enough estimates for experimental purposes. Initially the accuracy was improved
by using the Fresnel approximation for the calculation of physical flux. Obviously
this approach includes all the common approximations of scalar diffraction theories,
namely scalar field, infinitely thin aperture and perfectly absorbing screen. Therefore,
a more accurate model is introduced that accounts for the vector nature of
light, finite thickness for the aperture and infinite conducting screen which is a
good approximation because of the use of longer wavelengths. The application of
this model, as well as abandoning the single wavelength approximation, results in
deviations from scalar theory of 1% for a typical radiometric configuration.
Date Issued
2008-06
Date Awarded
2008-08
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Torok, Peter
McCall, Martin
Creator
Gogornas, Alexandros
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)