#!/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_Si/nm
m[0, 2] = index_Ag/nm

print "x =", x
print "m =", m

npts = 1001

scan = np.linspace(-4.0*x[0, 2], 4.0*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