(You purchase either ‘AZ’ or ‘AZ3’) The ‘Z’ option allows you to create diffractives and fresnels. DIFFSYS has become the industry standard for machining zoned surfaces.

DIFFSYS was originally developed for machining diffractives, and this our area of special expertise. Currently there is no international definitive specification for describing these zoned components, and over the past 10 years we have seen perhaps 15 different formats. Fortunately DIFFSYS can handle all of them. If you have a problem with entering a design, into DIFFSYS, we shall be pleased to help.

Diffractives and Fresnels.. What’s the difference? Diffractives generally have a fixed step height, which is related to the wavelength of the light being used, and is therefore usually between 1 and 5 microns. Fresnels generally have variable step heights, which tend to be much larger than the wavelength. See the diagram below.

Here is a mathematical curve, which has been setup in DIFFSYS. You can see how the same curve can be used to define a fixed-step-height diffractive, and also a variable-step-height fresnel. Note that in the lower case, the zone widths are constant.

The vertical scales have been greatly exaggerated, and normally, the diffractive would have much smaller steps than the fresnel.

Notice that the curve changes direction, and so do the step directions - DIFFSYS can handle this, although we do not see such designs very often.