zemax源码：

This DLL models an anamorphic aspheric surface.



This surface is essentially an even aspheric surface with different terms for

the x and y directions.



The sag is given by:



Z = ((CX*x*x)+(CY*y*y)) / (1 + sqrt(1-((1+KX)*CX*CX*x*x)-((1+KY)*CY*CY*y*y)))



+ AR*( (1 - AP)*x*x + (1 + AP)*y*y )^2

+ BR*( (1 - BP)*x*x + (1 + BP)*y*y )^3

+ CR*( (1 - CP)*x*x + (1 + CP)*y*y )^4

+ DR*( (1 - DP)*x*x + (1 + DP)*y*y )^5



Note the terms AR, BR, CR, and DR ... have units of length to the -3, -5, -7, and -9 power.



The terms AP, BP, CP, and DP are dimensionless.



The surface is rotationally symmetric only if AP = BP = CP = DP == 0 and CX = CY and KX = KY.