Binary 2A
The Binary 2A object has an even polynomial aspheric front and back face, with a diffractive optic phase profile similar to the Binary 2 surface type on the front face. The even aspheric sag formula is:
The Binary 2A object consists of two of these faces, separated by a thickness.
The Binary 2A phase profile is placed on the front face, and adds phase to a ray according to the following polynomial expansion:
where N is the number of polynomial coefficients in the series, Ai is the coefficient on the 2ith power of ρ , which is the normalized radial aperture coordinate. The coefficients Ai one wave).
The definitions for the parameters are:
| Parameter # | Description | Face Name | Face # |
| 1 | The Maximum Radial aperture. | NA | NA |
| 2 | The Thickness of the lens at the center. | Side | 0 |
| 3 | Clear Aperture of front surface | Front | 1 |
| 4 | Clear Aperture of back surface | Back | 2 |
| 5 | The front face radius of curvature. | Front | 1 |
| 6 | The front face conic constant k. | Front | 1 |
| 7-18 | The front face coefficients α1 – α12 . | Front | 1 |
| 19 | The back face radius of curvature. | Back | 2 |
| 20 | The back face conic constant k. | Back | 2 |
| 21-32 | The back face coefficients α1 – α12 . | Back | 2 |
| 33 | The diffraction order M. | Front | 1 |
| 34 | The normalization radius. The x and y coordinates are normalized to this value. This keeps all coefficients in units of radians. | Front | 1 |
| 35 | The maximum binary phase term number. | Front | 1 |
| 36-235 | The values of the coefficients on the polynomial terms. | Front | 1 |
Note: If Clear 1 or Clear 2 (Parameter 3 and 4) are equal to zero, Radial Aperture represents the Clear Aperture in the respective surface. If Clear 1 and/or Clear 2 are larger than zero, then Radial Aperture has an equivalent behavior of Edge 1 and/or Edge 2 (in Binary 2, for instance), creating flat surfaces and representing the radial aperture to the edge of the front side of the lens.
See also the Binary 1 and Binary 2 objects. For important information on diffractive objects, see "Diffraction from NSC objects". The reference coordinate is the center of the front face.
Face Numbers: Front face Face 1, back face Face 2, all other faces Face 0.
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