Data-Based Source [x-Domain]¶

Description¶

This Source Twin is defined by given electric field data rather than by analytical formulas. It enables reuse of simulated fields from other optical setups, measured field profiles, or externally generated field data as a light source.

The field data must be provided in the spatial domain (x-domain) and consist of a single optical mode. The data is loaded as a 2D array containing the \(E_x\) and/or \(E_y\) components along with the wavefront phase. This allows you to faithfully reproduce arbitrary optical fields and use them as the starting point for new simulations.

Model Parameters¶

The twin is configured by providing the following data. All data must be defined on a consistent 2D grid (same sampling and number of points).

• Electromagnetic Field: A single 2D data array containing at least one or two subsets, representing either \(E_x\), \(E_y\), or both components in the x-domain. This array fully defines the field's amplitude, polarization, and component-specific phases.
• Wavefront Phase \(\psi(\rho)\): A real-valued array representing the common wavefront phase. This is the phase shared by all field components, typically arising from optical path length differences. If no wavefront phase is provided, a planar wavefront (constant phase) is assumed.

Note: The wavelength \(\lambda\) of the source is not part of the loaded field data. It is configured as a separate parameter in the source's spectrum settings (see Software Usage below).

Simulation Model¶

The model requires the \(E_x\) and \(E_y\) component. If just one is given, the other is assumed to be zero. From such two components, all other relevant field quantities can be derived to fully characterize the source. This ensures a complete and physically consistent electromagnetic field description for subsequent propagation through the optical system.

Typical Application Scenarios¶

1. Cascading Optical Systems: Use the output field from a complex simulation (e.g., light passing through a diffuser or a multi-lens system) as the input source for a subsequent optical system, enabling true multi-stage simulations.
2. Importing Measured Beam Profiles: Load experimentally measured beam data into the simulation to analyze how a real-world beam will propagate through or interact with your optical design.
3. Simulating Custom Laser Modes: Create a source for a specific, non-standard laser mode by generating its field profile with an external tool (e.g., MATLAB, Python) and importing it for use in VLF.

Software Usage¶

1. Prepare Field Data: Obtain your electromagnetic field data and the optional wavefront phase \(\psi(\rho)\). This data can be:
   • Imported from an external file (ensure the format is compatible with VLF's data import tools).
   • Calculated in another VLF optical setup and captured using a Field Monitor detector, which can directly provide the wavefront phase.
2. Add the Twin: From the Digital Twin Hub, search for "Data-Based Source" or code SF-SDAT01 and add the twin to your document.
3. Load Field Data:
   1. Open the source's settings dialog.
   2. Navigate to the Spatial Distribution tab.
   3. Click the "Set" button next to the field data options.
   4. Load your electric field array. If you have a wavefront phase array, load it in the designated field. If none is loaded, a planar wavefront is assumed.
4. Set the Spectrum: Go to the Spectrum tab in the source's settings and set the correct wavelength \(\lambda\).
5. System Integration: Connect the source twin to other components (lenses, objects) and detectors to build your system and analyze the propagation of your custom field.