Release from Electric Field
This feature is only available if the ray intensity or power is solved for. Select an appropriate option from the Intensity computation list in the physics interface Intensity Computation section.
Use the Release from Electric Field node to release rays from selected boundaries, with initial intensity and polarization based on the incident electric field at that boundary. The electric field may be user defined or solved for in a previous study.
See Release for information on the Initial Values of Auxiliary Dependent Variables section and the optional Release Times section. See Release from Boundary for information on the Initial Position section.
Ray Direction Vector
Select an option from the Ray direction vector list: Parallel to Poynting vector, Outward normal (the default), or Inward normal. For Outward normal and Inward normal the direction of the released rays is indicated by an arrow in the Graphics window.
The Parallel to Poynting vector option can be useful when the outgoing wave makes an oblique angle with an absorbing boundary, such as a Port, Scattering Boundary Condition, or Matched Boundary Condition; or when the simulation domain is surrounded by a Perfectly Matched Layer. In those scenarios, releasing the rays normal to the surface might not be accurate.
It is not sufficient to only know the electric field at the surface; it must be differentiable in both the tangential and normal directions. Usually this means that selecting an Electric field defined by one of the Electromagnetic Waves interfaces will work, but selecting a Tangential electric field will fail.
Incident Electric Field
Enter values or expressions in the table for the Electric field E (SI unit: V/m) based on space dimension. If the electric field is computed by another physics interface then it can be selected from the list.
The Use frequency from the coupled physics interface as the ray frequency check box is cleared by default. If this check box is cleared, the wavelength or frequency of the released rays may be specified depending on the option selected from the Wavelength distribution of released rays list in the physics interface Ray Release and Propagation section:
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If Polychromatic, specify vacuum wavelength is selected, enter the Vacuum wavelength λ0 (SI unit: m). The default is 660 nm.
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If Polychromatic, specify frequency is selected, enter the Ray frequency ν (SI unit: 1/s). The default is 4.54 × 1014 Hz.
If this check box is selected, then the frequency or wavelength of the released rays will be determined by the Frequency Domain or Wavelength Domain study in the Values of Variables not Solved For section of the Time Dependent solver settings. Typically this Frequency Domain or Wavelength Domain study would first be used to solve for the electric field, using either the Electromagnetic Waves, Frequency Domain interface or the Electromagnetic Waves, Beam Envelopes interface.
Selecting this check box may also cause the frequency or wavelength specified in the Ray Properties node to be ignored while the Release from Electric Field node is active.
In the Geometrical Optics interface, ray intensity is stored in the Stokes parameters for each ray. For more information, see Intensity, Wavefront Curvature, and Polarization in Theory for the Geometrical Optics Interface.
Ray Release Based on a Plane Electromagnetic Wave: Application Library path Ray_Optics_Module/Tutorials/plane_em_wave_to_ray_release