Input system

PAOS has a generic input system to be used by anyone expert in Computer Aided Design (CAD).

Its two pillars are

1. The Configuration file

   A .ini configuration file with structure similar to that of Zemax OpticStudio \(^{©}\);

2. The GUI editor

   A GUI to dynamically modify the configuration file and launch instant POP simulations

This structure allows the user to write configuration files from scratch or edit existing ones in a dynamic way, and to launch automatized POP simulations that reflect the edits without requiring advanced programming skills.

From a broad perspective, this input system has two advantages:

1. It can be used to design and test any optical system with relative ease.

   Outside Ariel, PAOS is currently used to simulate the optical performance of the stratospheric balloon-borne experiment EXCITE.

   Tip

   The interested reader may refer to the section Plotting results to see an example of PAOS results for EXCITE.

2. It helped in validating the PAOS code against existing simulators.

Configuration file

The configuration file is an .ini file structured into four different sections:

1. DEFAULT

   Optional section, not used

2. General

3. Wavelengths

4. Fields

5. Lens_xx

Note

PAOS defines units as follows:

1. Lens units: meters

2. Angles units: degrees

3. Wavelength units: micron

General

Section describing the general simulation parameters and PAOS units

Table 4 General

keyword	type	description
project	string	A string defining the project name
version	string	Project version (e.g. 1.0)
grid_size	int	Grid size for simulation Must be in [64, 128, 512, 1024]
zoom	int	Zoom size Must be in [1, 2, 4, 8, 16]
lens_unit	string	Unit of lenses Must be ‘m’
tambient	float	Ambient temperature in Celsius
pambient	float	Ambient pressure in atmospheres

Below we report a snapshot of this section from the Ariel AIRS CH1 configuration file

Fig. 3 General

Wavelengths

Section listing the wavelengths to simulate (preferably in increasing order)

Table 5 Wavelengths

keyword	type	description
w1	float	First wavelength
w2	float	Second wavelength
…	…	…

Below we report a snapshot of this section from the Ariel AIRS CH1 configuration file

Fig. 4 Wavelengths

Fields

Section listing the input fields to simulate

Table 6 Fields

keyword	type	description
f1	float, float	Field 1: sagittal (x) and tangential (y) angle
f2	float, float	Field 2: sagittal (x) and tangential (y) angle
…	…	…

Below we report a snapshot of this section from the Ariel AIRS CH1 configuration file

Fig. 5 Fields

Lens_xx

Lens data sections describing how to define the different optical surfaces (INIT, Coordinate Break, Standard, Paraxial Lens, ABCD and Zernike) and their required parameters.

Table 7 Lens_xx

SurfaceType	Comment	Radius	Thickness	Material	Save	Ignore	Stop	aperture	Par1..N
INIT	string, this surface name	None	None	None	None	None	None	list	None
Coordinate Break	…	None	float	None	Bool	Bool	Bool	list	None
Standard	…	float	float	MIRROR, others	Bool	Bool	Bool	list	None
Paraxial Lens	…	None	float	None	Bool	Bool	Bool	list	Par1 = focal length (float)
ABCD	…	None	float	None	Bool	Bool	Bool	list	Par1..4 = Ax, Bx, Cx, Dx (sagittal) Par5..8 = Ay, By, Cy, Dy (tangential)
Zernike in addition to standard parameters defines: Zindex: polynomial index starting from 0 Z: coefficients in units of wave	…	None	None	None	Bool	Bool	Bool	None	Par1 = wavelength (in micron) Par2 = ordering, can be standard, ansi, noll, fringe Par3 = Normalisation, can be True or False Par4 = Radius of support aperture of the polynomial Par5 = origin, can be x (counterclockwise positive from x axis) or y (clockwise positive from y axis)

Note

1. Set the Ignore flag to 1 to skip the surface

2. Set the Stop flag to 1 to make the surface a Stop (see Stops)

3. Set the Save flat to 1 to later save the output for the surface

Note

The aperture keyword is a list with the following format:

• aperture = shape type, wx, wy, xc, yc

• shape: either ‘elliptical’ or ‘rectangular’

• type: either ‘aperture’ or ‘obscuration’

• wx, wy: semi-axis of elliptical shapes, or full length of rectangular shape sides

• xc, yc: coordinates of aperture centre

Example: aperture = elliptical aperture, 0.5, 0.3, 0.0, 0.0

Below we report a snapshot of the first lens data section from the Ariel AIRS CH1 configuration file

Fig. 6 Lens_xx

Parse configuration file

PAOS implements the method parse_config that parses the .ini configuration file, prepares the simulation run and returns the simulation parameters and the optical chain. This method can be called as in the example below.

Example

Code example to parse a PAOS configuration file.

from paos.core.parseConfig import parse_config
pup_diameter, parameters, wavelengths, fields, opt_chains = parse_config('path/to/ini/file')

GUI editor

PAOS implements a GUI editor that allows to dynamically edit and modify the configuration file and to launch POP simulations. This makes it effectively the PAOS front-end. To achieve this, PAOS uses the PySimpleGui package, a Python package that aims at “bridging the GUI gap between software developers and end users”.

The quickest way to run the PAOS GUI is from terminal.

Run it with the help flag to read the available options:

$ paosgui --help

Table 8 GUI command line flags

flag	description
-h, --help	show this help message and exit
-c, --configuration	Input configuration file to pass
-o, --output	Output file path
-d, --debug	Debug mode screen
-l, --logger	Store the log output on file

Where the configuration file shall be an .ini file (see Configuration file). If no configuration file is passed it defaults to the configuration template template.ini file. To activate -d and -l no argument is needed.

The GUI editor then opens and displays a GUI window with a standard Menu (Open, Save, Save As, Global Settings, Exit) and a series of Tabs:

1. General Tab

2. Fields Tab

3. Lens data Tab

   Zernike Tab

4. Launcher Tab

5. Monte Carlo Tab

6. Info Tab

On the bottom of the GUI window, there are five Buttons to perform several actions:

• Submit:

  Submits all values from the GUI window in a flat dictionary

• Show Dict:

  Shows the GUI window values in a nested dictionary, organized into the same sections as the configuration file

• Copy to clipboard:

  Copied the nested dictionary to the local keyboard

• Save:

  Saves the GUI window to the configuration file upon exiting

• Exit:

  Exits the GUI window

The GUI window defines also a right-click Menu with the following options:

• Nothing:

  Does nothing

• Version:

  Displays the current Python, tkinter and PySimpleGUI versions

• Exit:

  Exits the GUI window

General Tab

This Tab opens upon starting the GUI. Its purpose is to setup the main simulation parameters.

It contains two Frames:

• General Setup

  Displays the general simulation parameters and PAOS units, as defined in General. The contents can be altered as necessary, safe if the the cells are disabled.

• Wavelength Setup

  Lists the wavelengths to simulate. This list can be altered by editing the wavelengths. The user can use the Buttons in the Wavelengths Actions Frame to modify the list content by adding new wavelength rows, pasting a list of wavelengths from the local clipboard (\(\textit{comma}\)-separated or \(\backslash n\)-separated) and can also be sort the list to increasing order.

Below we report a snapshot of this Tab.

Fig. 7 General Tab

Fields Tab

This GUI Tab describes the input fields to simulate.

In the Fields Setup Frame it lists the input fields, as defined in Fields.

The fields contents can be edited as necessary and new fields can be added by clicking on the Add Field Button in the Fields Actions Frame.

Note

While more than one field can be listed in this Tab, the current version of PAOS only supports simulating one field at a time

Below we report a snapshot of this Tab.

Fig. 8 Fields Tab

Lens data Tab

This GUI Tab contains the list of the optical surfaces describing the optical chain to simulate, as defined in Lens_xx.

This information is organized in the Lens Data Setup Frame, whose structure tries to mimic that of Zemax OpticStudio \(^{©}\). The columns are arranged as explained in Lens_xx, with horizontal and vertical scrollbars to allow any movement.

The contents of each row can be edited as necessary and new surfaces can be added by clicking on the Add Surface Button in the Lens Data Actions Frame.

For each row, columns are automatically enabled/disabled according to the surface type.

Below we report a snapshot of this Tab.

Fig. 9 Lens data Tab

Tip

The column headers for Par1..N change according to the cursor position in the Table.

Tip

It is possible to move the cursor with arrow keys.

Tip

To see/edit the contents of the aperture column, click on the Button with the yellow triangle.

Zernike Tab

This GUI Tab can be accessed from the Lens Data Tab, by selecting a Zernike surface in the Dropdown menu from the SurfaceType column. Then, a small window appears asking to proceed with the insertion or modification of Zernike coefficients. A positive answer opens the Zernike Tab.

It contains two Frames:

• Parameters

  Displays the Zernike parameters as defined in the Lens Data Tab and serves as a reminder to the user. It is not enabled to be modified, which needs to be done beforehand in the Lens Data Tab.

• Zernike Setup

  Contains a Table that lists the Zernike polynomial index (“Zindex”), the Zernike coefficients (“Z”), and the azimuthal (“m”) and radial (“n”) polynomial orders, according to the specified Zernike ordering (one of standard, ansi, fringe and noll). Only the “Z” column is enabled to be modified as required by the user.

  The user can use the Buttons in the Zernike Actions Frame to modify the Table content by adding new rows, completing an unclosed Zernike radial order or adding a new one (available only if using standard or ansi ordering), and by pasting a list of Zernike coefficients from the local clipboard (\(\textit{comma}\)-separated or \(\backslash n\)-separated) in a cell from the “Z” column to automatically create and fill all necessary rows. The other columns will update accordingly.

Below we report a snapshot of this Tab.

Fig. 10 Zernike Tab

Launcher Tab

This GUI Tab is designed to make preliminary, fast simulations to test a new configuration file or to simulate the propagation for a particular wavelength at a time.

It contains three Frames:

• Select inputs

  Allows to select the simulation wavelength and field. By selecting a new wavelength or field, the outputs of this Tab are reset, except for the raytrace output if the field has not changed.

• Run and Save

  Contains Buttons to call PAOS methods to run the simulation.

  The Raytrace Button runs a diagnostic ray-trace of the optical system, producing an output that is displayed in the Multiline element below it. This output can be saved to a text file by using the Save raytrace Button.

  The POP Button runs the wavefront propagation, producing an output dictionary that can be saved to a binary (.hdf5) file using the Save POP Button.

  The Plot Button plots the squared amplitude of the wavefront with the selected zoom factor at the selected surface from the Dropdown menu. The plot scale can be selected to be logarithmic or linear. Use the Save Plot Button to save the produced plot.

• Display

  Allows to see the simulation output plot. To display it, use the Display plot Button.

Below we report a snapshot of this Tab.

Fig. 11 Launcher Tab

Monte Carlo Tab

This GUI Tab is designed to provide support for specific Monte Carlo simulations.

Two kinds of such simulations are currently supported:

1. Running the optical system at all provided wavelengths at once.

2. Running the optical system with different aberration realizations.

Therefore, the Tab contains two (collapsible) Frames, each with a layout similar to Launcher Tab:

• MC Wavelengths

  Provides GUI support for running all provided wavelengths using parallel execution.

  The user can select a field in the Select Inputs Frame, a number of parallel jobs, and then run the propagation by clicking on the POP Button. The simulation output can then be saved to a binary (.hdf5) file using the Save POP Button.

  The Plot Button plots the squared amplitude of the wavefront for the selected range of simulations, which is automatically estimated from the simulation output but can be customized as needed. The plots can be customized by selecting the zoom factor, the surface to plot and the plot scale. Use the Save Plot Button to save the produced plots. To uniquely label the plots to be saved, please change the default figure prefix.

  To display the plots, use the Display plot Button and the Slider element to see all plotted instances.

  Below we report a snapshot of this Frame.

  

  Fig. 12 Monte Carlo Tab (1)

• MC Wavelengths

  Provides GUI support for running the propagation with different aberration realizations using parallel execution.

  The user can select the wavelength and field in the Select Inputs Frame.

  The .csv file with the aberration realizations can be imported using the Import wfe Button. To indicate the unit of the Zernike coefficients (r.m.s.), use the Dropdown menu below it.

  After this, select the number of parallel jobs, indicate the index of the Zernike surface (the corresponding row in the Lens data Tab and run the propagation using the POP Button. The simulation output can then be saved to a binary (.hdf5) file using the Save POP Button.

  To plot, save and display the simulation output, please refer to the preceding paragraph MC Wavelengths.

  Below we report a snapshot of this Frame.

  

  Fig. 13 Monte Carlo Tab (2)

Info Tab

This GUI Tab contains information about the PAOS creators and the GUI.

It displays:

• The author names

• The PAOS version

• The Github repository

• The PySimpleGui version and release

Below we report a snapshot of this Tab.

Fig. 14 Info Tab