---   RI332  ---

 Finite Gratings at High Frequancies: Part I, The Helmholtz equation
                             H. Ammari

 Abstract:
 We construct geometric-optics solution to a problem
 of scattering of the Helmholtz equation by a finite periodic dielectric grating placed on the interface
 between semi-infinite dielectric media. The first order approximation
 is the solution of the infinite periodic grating.
 
The whole paper is available as a compressed Postscript file by internet
procedure FTP anonymous on host barbes.polytechnique.fr ( 129.104.4.100)
in the directory pub/RI/1995 under the name

         ammari_332.sept.ps.gz

or by Xmosaic or any other www client
via the CMAP www server "http://blanche.polytechnique.fr/"