Added calculation of field across X axis for SiAgSi structure

tests/python/lfield-SiAgSi.py

@@ -0,0 +1,110 @@
+#!/usr/bin/env python
+# -*- coding: UTF-8 -*-
+#
+#    Copyright (C) 2009-2015 Ovidio Peña Rodríguez <ovidio@bytesfall.com>
+#
+#    This file is part of python-scattnlay
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    The only additional remark is that we expect that all publications
+#    describing work using this software, or all commercial products
+#    using it, cite the following reference:
+#    [1] O. Pena and U. Pal, "Scattering of electromagnetic radiation by
+#        a multilayered sphere," Computer Physics Communications,
+#        vol. 180, Nov. 2009, pp. 2348-2354.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This test case calculates the electric field in the 
+# E-k plane, for an spherical Si-Ag-Si nanoparticle. Core radius is 17.74 nm,
+# inner layer 23.31nm, outer layer 22.95nm. Working wavelength is 800nm, we use
+# silicon epsilon=13.64+i0.047, silver epsilon= -28.05+i1.525
+
+import scattnlay
+from scattnlay import fieldnlay
+import numpy as np
+
+# epsilon_Si = 13.64 + 0.047j
+# epsilon_Ag = -28.05 + 1.525j
+epsilon_Si = 2.0 + 0.047j
+epsilon_Ag = -2.0 + 1.525j
+
+index_Si = np.sqrt(epsilon_Si)
+index_Ag = np.sqrt(epsilon_Ag)
+
+# Values for 800 nm, taken from http://refractiveindex.info/
+index_Si = 3.69410 + 0.0065435j
+index_Ag = 0.18599 + 4.9886j
+
+WL=800 #nm
+core_width = 17.74 #nm Si
+inner_width = 23.31 #nm Ag
+outer_width = 22.95 #nm  Si
+
+core_r = core_width
+inner_r = core_r+inner_width
+outer_r = inner_r+outer_width
+
+# n1 = 1.53413
+# n2 = 0.565838 + 7.23262j
+nm = 1.0
+
+x = np.ones((1, 3), dtype = np.float64)
+x[0, 0] = 2.0*np.pi*core_r/WL
+x[0, 1] = 2.0*np.pi*inner_r/WL
+x[0, 2] = 2.0*np.pi*outer_r/WL
+
+m = np.ones((1, 3), dtype = np.complex128)
+m[0, 0] = index_Si/nm
+m[0, 1] = index_Ag/nm
+m[0, 2] = index_Si/nm
+
+print "x =", x
+print "m =", m
+
+npts = 281
+
+scan = np.linspace(-2.0*x[0, 2], 2.0*x[0, 2], npts)
+
+coord = np.zeros((npts, 3), dtype = np.float64)
+coord[:, 0] = scan
+
+terms, E, H = fieldnlay(x, m, coord)
+
+Er = np.absolute(E)
+
+# |E|/|Eo|
+Eh = np.sqrt(Er[0, :, 0]**2 + Er[0, :, 1]**2 + Er[0, :, 2]**2)
+
+result = np.vstack((scan, Eh)).transpose()
+
+try:
+    import matplotlib.pyplot as plt
+
+    fig = plt.figure()
+    ax = fig.add_subplot(111)
+
+    ax.errorbar(result[:, 0], result[:, 1], fmt = 'r', label = 'X axis')
+
+    ax.legend()
+
+    plt.xlabel('X')
+    plt.ylabel('|E|/|Eo|')
+
+    plt.draw()
+    plt.show()
+finally:
+    np.savetxt("lfield.txt", result, fmt = "%.5f")
+    print result
+
+