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  {
   "cell_type": "markdown",
   "id": "996ae31d-192b-4988-bd6b-649c833ae967",
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   "source": [
    "# Gaussian laser pulse"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "f25efcc9-1ed0-4f9a-8c62-da36f56ba02f",
   "metadata": {},
   "source": [
    "We will try a simple example to get familiar with the code structure and to verify the installation was successful.\n",
    "Let's generate a Gaussian pulse at focus, propagate it backwards by one Rayleigh length (the pulse is then located upstream of the focal plane) and then output it to a file.\n",
    "\n",
    "First let's load in the required functions from the library."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "ed0a409c-3c02-4fc4-b41b-ef41d0fb5a3a",
   "metadata": {},
   "outputs": [],
   "source": [
    "from lasy.laser import Laser\n",
    "from lasy.profiles.gaussian_profile import GaussianProfile"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "83519896-2653-4895-8d90-789c4f0729ae",
   "metadata": {},
   "source": [
    "Next, define the physical parameters of the laser pulse and create the laser profile object."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "15491762-c2d5-4b65-8cd3-4633a4cb7eff",
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   "source": [
    "wavelength = 800e-9  # Laser wavelength in meters\n",
    "polarization = (1, 0)  # Linearly polarized in the x direction\n",
    "energy = 1.5  # Energy of the laser pulse in joules\n",
    "spot_size = 25e-6  # Waist of the laser pulse in meters\n",
    "pulse_duration = 30e-15  # Pulse duration of the laser in seconds\n",
    "t_peak = 0.0  # Location of the peak of the laser pulse in time\n",
    "\n",
    "laser_profile = GaussianProfile(\n",
    "    wavelength, polarization, energy, spot_size, pulse_duration, t_peak\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "c303d3b6-2422-445b-a332-bc3f48388612",
   "metadata": {},
   "source": [
    "Now create a full laser object containing the above physical parameters together with the computational settings."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "84cb6fd2-2f44-4cc9-a5c1-6dd1e0d72c67",
   "metadata": {},
   "outputs": [],
   "source": [
    "dimensions = \"rt\"  # Use cylindrical geometry\n",
    "lo = (0, -2.5 * pulse_duration)  # Lower bounds of the simulation box\n",
    "hi = (5 * spot_size, 2.5 * pulse_duration)  # Upper bounds of the simulation box\n",
    "num_points = (300, 500)  # Number of points in each dimension\n",
    "\n",
    "laser = Laser(dimensions, lo, hi, num_points, laser_profile)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "8ac8f985-4a09-4b9a-a9ff-11ce2ef94caa",
   "metadata": {},
   "source": [
    "The laser pulse can be visualized with the `show` method."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "bb8dc634-b3c4-4448-834b-fe9acb6c9645",
   "metadata": {},
   "outputs": [],
   "source": [
    "laser.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "292c6e63-0480-4fb9-b1ad-6b679a3472d0",
   "metadata": {},
   "source": [
    "By default, the values of the laser envelope are injected on the focal plan. One can propagate it backwards by one Rayleigh length (optional)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "00b4f258-ca10-4bc7-b550-75fb10c3603a",
   "metadata": {},
   "outputs": [],
   "source": [
    "z_R = 3.14159 * spot_size**2 / wavelength  # The Rayleigh length\n",
    "laser.propagate(-z_R)  # Propagate the pulse upstream of the focal plane"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3158e51d-e331-438d-90c1-5f8c63bf9841",
   "metadata": {},
   "outputs": [],
   "source": [
    "laser.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "8df816dc-9b47-4cb0-8716-600352fafb72",
   "metadata": {},
   "source": [
    "Output the result to a file. Here we utilise the openPMD standard."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b6a4c66b-651e-40b7-b15e-53f8a27caeb2",
   "metadata": {},
   "outputs": [],
   "source": [
    "file_prefix = \"test_output\"  # The file name will start with this prefix\n",
    "file_format = \"h5\"  # Format to be used for the output file\n",
    "\n",
    "laser.write_to_file(file_prefix, file_format)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "1edc3e0b-f88a-4a8a-8802-3d5ec9098f9c",
   "metadata": {},
   "source": [
    "The generated file may now be viewed or used as a laser input to a variety of other simulation tools."
   ]
  }
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