{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import matplotlib.pyplot as plt\n",
    "import numpy as np\n",
    "from solcore.absorption_calculator import calculate_ellipsometry\n",
    "from solcore import material, si\n",
    "from solcore.structure import Structure, Layer"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First we defined a couple of materials, for example, GaAs and AlGAs"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "GaAs = material('GaAs')(T=300)\n",
    "AlGaAs = material('AlGaAs')(T=300, Al=0.3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now, let's build the structure. We don't add a substrate and assume that there is an infinitely thick absorbing<br>\n",
    "material in the back."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "my_structure = Structure([\n",
    "    Layer(si(40, 'nm'), material=AlGaAs),\n",
    "    Layer(si(3000, 'nm'), material=GaAs),\n",
    "])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We want to calculate the ellipsometry of this structure as a function of the wavelength for a few angles"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "wavelength = np.linspace(400, 1000, 200)\n",
    "angles = [65, 70, 75]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "out = calculate_ellipsometry(my_structure, wavelength, angle=angles)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This results must be taken with care. As the ellipsometry routine can only deal with coherent light, there might be<br>\n",
    "strange oscillations related with intereference in thick layers, something that should not happen.<br>\n",
    "Setting no_back_reflection=True (the default) should take care of most of this effects, but might add other unexpected<br>\n",
    "ones."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "fig, ax1 = plt.subplots(1, 1)\n",
    "ax2 = ax1.twinx()\n",
    "\n",
    "ax1.plot(wavelength, out['psi'][:, 0], 'b', label=r'$\\Psi$')\n",
    "ax2.plot(wavelength, out['Delta'][:, 0], 'r', label=r'$\\Delta$')\n",
    "for i in range(1, len(angles)):\n",
    "    ax1.plot(wavelength, out['psi'][:, i], 'b')\n",
    "    ax2.plot(wavelength, out['Delta'][:, i], 'r')\n",
    "\n",
    "ax1.set_xlabel(\"Wavelength (nm)\")\n",
    "ax1.set_ylabel(r'$\\Psi$ (º)')\n",
    "ax2.set_ylabel(r'$\\Delta$ (º)')\n",
    "\n",
    "ax1.legend(loc=\"upper left\")\n",
    "ax2.legend(loc=\"upper right\")\n",
    "\n",
    "plt.show()"
   ]
  }
 ],
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