DSpace
 

RRI Digital Repository >
06. Soft Condensed Matter >
Research Papers (SCM) >

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/757

Title: Geometrical theory of diffraction
Authors: Sunil Kumar, P.B.
Ranganath, G.S.
Keywords: Diffraction
Fresnel diffraction
Boundary waves
Issue Date: Dec-1991
Publisher: Indian Academy of Sciences, Bangalore, India.
Citation: Pramana, 1991, Vol. 37, p457-488.
Abstract: Geometrical theory of diffraction (GTD) is an alternative model of diffraction propounded first by Thomas Young in 1802. GTD has a long history of nearly 150 years over which many eminent people enriched this model which has now become an accepted tool in the calculation of diffraction patterns. In the conventional Helmholtz-Kirchholf theory the diffracted field is obtained by computing the net effect of the waves emitted by all points within the area of the aperture. But GTD reduces this problem to one of computing the net effect of waves from a few points on the boundary of the aperture or obstacle, thus simplifying considerably the labour involved in computations. Also the theory can easily be modified: to include polarization effects. This has been done specifically by Keller (1962) who exploited the Sommerfeld solution of diffraction of electromagnetic waves at a half plane, making the theory more versatile than the Kirchhoff scalar wave theory. Interestingly the geometry of difiacred rays is predictable from a generalized Fermat principle. According to this the total path chosen by light from the source to the point of observation via the diffracting boundary is an extremum. Historically it should be stated that many of the salient features of GTD were established by a school led by Raman which was active from 1919-1945. Later when Keller (1962) revived GTD independently, he and others who followed him rediscovered many of the results of the Raman school. We have stressed wherever necessary the contributions of the Indian School. We have also discussed certain geometries where GTD can be effectively used. We get some new and interesting results, which can be easily , understood on GTD, but are dificult to interpret on the conventional theory of diffraction.
URI: http://hdl.handle.net/2289/757
ISSN: 0304-4289
Copyright: Indian Academy of Sciences, Bangalore, India.
Appears in Collections:Research Papers (SCM)

Files in This Item:

File Description SizeFormat
1991 Pramana V37 p457.pdf31p.1.45 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

    RRI Library DSpace