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SCATMECH > Classes and Functions >
Surface Scattering Models
> RCW_BRDF_Model
class
RCW_BRDF_Model
The class RCW_BRDF_Model provides a BRDF_Model
interface to the RCW_Model. Since a periodic structure
yields delta-function-like peaks in the BRDF, the BRDF cannot be strictly evaluated
for such a structure. However, it is sometimes useful to provide a mechanism for
evaluating an effective BRDF. This model provides that interface by spreading the
power of each diffracting order uniformly over a conical solid angle whose
half-angle is given by the parameter alpha.
Parameters:
| Parameter |
Data
Type |
Description |
Default |
| lambda |
double |
Wavelength of the light
in vacuum [µm].
(Inherited from BRDF_Model).
|
0.532 |
| type |
int |
Indicates
whether scattering is evaluated in reflection (0) or
transmission (1).
(Inherited from BRDF_Model).
|
0 |
| substrate |
dielectric_function |
The
optical constants of the substrate, expressed as a
complex number (n,k) or, optionally, as a function of
wavelength.
(Inherited from BRDF_Model).
|
(4.05,0.05) |
| alpha |
double |
The half-angle of
a cone over which the power diffracted into
each order is assumed to be spread [rad]. |
0.0175 |
| order |
int |
The
Fourier order considered in the calculation. The
calculation will expand the dielectric function in a
layer from -order to order. |
25 |
| oldmethod |
int |
Indicates
whether or not the extension by Lalanne and Morris is
used. If oldmethod is 1, then the theory is implemented
as described by Moharam, et al., which typically
converges very slowly for transverse-magnetic (TM)
polarization. If oldmethod is 0, then the extension
described by Lalanne and Morris is used, which usually
results in much faster convergence. |
0 |
| grating |
Grating_Ptr |
A
description of the grating profile and optical
properties. |
Single_Line_Grating |
See also:
SCATMECH Home, Conventions, BRDF_Model,
RCW_Model,
Grating
M.G. Moharam, E.B. Grann, D.A. Pommet, and T.K. Gaylord,
"Formulation for stable and efficient implementation of the
rigorous coupled-wave analysis of binary gratings," J. Opt.
Soc. Am. A 12, 1068-1076 (1995).
P. Lalanne and G.M. Morris, "Highly improved convergence of
the coupled-wave method for TM polarization" J. Opt. Soc.
Am. A 13, 779-784 (1996).
G. Granet and B. Buizal, "Efficient implementation of the coupled-wave method
for metallic lamellar gratings in TM polarization," J. Opt. Soc. Am. A 13, 1019-1023 (1996).
L. Li, "Use of Fourier series in the analysis of discontinuous periodic structures," J. Opt. Soc. Am. A 13, 1870-1876 (1996).
Include file:
#include "rcw.h"
Source code:
rcw.cpp
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Current SCATMECH version: 6.00 (February 2008)
This page first online: Version 6.00 (February 2008)
This page last modified: Version 6.00 (February 2008)
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