Propagation Options Panel

The Propagation Options Panel is used to specify what types of calculations are used to model the light as it propagates through a lens group.

Propagations Options :

The Propagations options

propagation_panel.propagation_options

Source To Entrance Pupil Calculation

propagation_panel.src2enp

  • Low NA (Fourier) – The source (object) propagates to a plane in the entrance pupil of the lens. This option is highly discouraged for most problems due to large quadratic phase factors. Instead, use the High NA option. The result is regularly spaced in the entrance pupil.
  • High NA (dir cos) – The source (object) propagates to a reference sphere centered in the entrance pupil of the lens. The outside edge of the reference sphere coincides with the edge of the entrance pupil. It is recommended to use this option even with low-NA systems in order to avoid large quadratic phase factors. The result is regularly spaced in the entrance pupil.
  • Huygens – If the Huygens options is selected, then the “Nsource” edit is enabled. The source fields are resampled based on this parameter. A Huygens integration is then performed to each point on a curved reference sphere in the entrance pupil. The number of points across the diameter of the entrance pupil is Npupil.
  • Direct Curved – Direct input for field data on a reference sphere in the entrance pupil of the lens.
  • Direct Planar – Direct input for field data on a reference plane in the entrance pupil of the lens. Care must be taken to provide the proper phase distribution with this option.
  • None – No calculations are performed on the input fields at this point.

Entrance Pupil to Exit Pupil Calculation

propagation_panel.enp2exp

  • ABCD – A simple first-order propagation between the entrance pupil and exit pupil is assumed with a magnification scaling. The input field into the entrance pupil does not need to be regularly spaced.
  • Ray – A general-purpose option that traces a grid of rays through the optical system and determines the optical aberrations in the exit pupil, the cutoff of energy by the stop, and the pupil aberrations. If the Ray Trace option is selected, then the “Nrays_x” and “Nrays_y” edits are enabled. This parameters determine the number of grid points (Nrays_x * Nrays_y) for the Ray Trace. (To date – not fully tested.)
  • ABCD : direct – A simple first-order propagation routine between the entrance pupil and exit pupil is assumed with a magnification scaling. The input field into the entrance pupil needs to be regularly spaced. For most applications, this is the appropriate option because it is fast.
  • Reserved – Not used at this time.
  • Reserved – Not used at this time.
  • None – No calculations are performed on the input fields at this point.

Exit Pupil to Target Calculation

propagation_panel.exp2tar

  • Low NA (Fresnel) – The field in the plane of the exit pupil propagates to the target plane. This option is highly discouraged for most problems due to large quadratic phase factors. Instead, use the High NA option.
  • High NA (dir cos) – The field in the exit pupil reference sphere propagates to the target plane. The outside edge of the reference sphere coincides with the edge of the exit pupil. It is recommended to use this option even with low-NA systems in order to avoid large quadratic phase factors.
  • Fresnel – The field in the exit pupil reference sphere propagates to an out-of focus plane based on the effective Fresnel number. One application for this option is to describe light shining on a out-of focus detector. This option should not be used when the last surface of the lens is near a focal plane.
  • Huygens – The field in the exit pupil is integrated point-by-point to calculate the field in the target plane. The target sampling grid is determined by the target window. In the present configuration, this option is used only with the mll target to calculate a one-dimensional profile.
  • None : Curved EXP – The output field is the field on a curved reference sphere centered in the exit pupil.
  • None : Planar EXP – The output field is the field on a planar surface in the exit pupil.

Electromagnetic Calculation Portion :

The Electromagnetic Calculation panel is used to

propagation_panel.electromagnetic_calculation

  • Scalar – The x, y and z electromagnetic fields are propagated independently and no polarization mixing is calculated.
  • Vector – When focusing beams from the exit pupil to the target, polarization mixing is calculated in order to determine the proper spot profiles.