CODE V Enewsletter

February 2015

Quick Tip: Conditions and Assumptions in CODE V Diffraction Calculations

CODE V features many different methods of considering diffraction in optical systems. The PSF option for analyzing a point spread function, MTF for analyzing a modulation transfer function, and BSP for simulating general beam propagation are relied upon by many engineers working with systems where diffraction matters.

All diffraction calculations in CODE V are based on equations that assume Kirchhoff boundary conditions (which, in turn, assume that the edge of an aperture is a perfect conductor, so that the E field goes to zero at the edge).1 Even though Kirchhoff boundary conditions are seldom met at optical frequencies, this is a reasonable assumption as long as the apertures are larger than about 10λ. For smaller apertures, edge effects become significant.

For features that are much larger than 10λ (>~100λ), then CODE V geometrical ray tracing tools are appropriate as waves can be approximated by straight lines. When features are smaller than 10λ, more computationally intensive methods that solve Maxwell’s equations are needed.2


  1. Born & Wolf, Principles of Optics (see section 8.3.2 of the 4th edition [1970]).
  2. Synopsys RSoft products are applicable in these small wavelength regions.

CODE V Glass Catalog Updates Available for Download

Updates to the CODE V glass catalog, including the Ohara and Schott manufacturers’ catalogs, are now available for download on our website at

OSA Freeform Optics Conference

OSA is sponsoring a Freeform Optics conference on June 7-11, 2015, which is co-chaired by one of our engineers, Dr. Kevin Rolland-Thompson, Group Director, Research and Development, Optics. Invited speakers from both industry and academia are scheduled to speak on the latest developments on optical design, optical system simulation, surface representation, and more. A presentation will be made by Dr. Bill Cassarly of Synopsys entitled "Assessing freeform illumination surface tolerances."

The conference will be held at the Renaissance Arlington Capital View Hotel in Arlington, Virginia. For more details, please visit the OSA website. Online registration for this conference will open on March 2.