Solved

Cylindrical lenses in Zemax sequential mode

  • 1 December 2022
  • 1 reply
  • 712 views

  • Single Emitter
  • 0 replies

Hi, I have a question with regards to how Zemax handles cylindrical/biconic systems. If I have a lens system where the say I have a pair of cylindrical lenses with two different focal lengths rotated 90 degrees about the light propagation axis, i.e. the system would have two different EFL, NA in the x, y axis, how does Zemax calculate parameters such as imaging NA, EFL, Seidel sums etc.? I noticed for example, for Seidel sums, Zemax does not break up the calculation of Seidel sums into two separate transverse axis but just gives one set of numbers. Zemax also gives the imaging NA, EFL data in the system data as one number instead of say two in two different axis. Is there a way to be able to get data for x and y separately? Thanks!

icon

Best answer by David.Nguyen 1 December 2022, 11:51

View original

1 reply

Userlevel 7
Badge +2

Hi boon,

 

I’m note quite sure, but I did a simple test with the Paraxial XY surface, and it seems like EFFL is calculated in the Y-Z plane.

Paraxial XY Surface, Conf 1: optical power in X-Z plane, Conf 2: optical power in Y-Z plane

I did a similar test with the Biconic surface, and got the same behaviour.

Biconic Surface, Conf 1: optical power in X-Z plane, Conf 2: optical power in Y-Z plane

Basically, only the optical power in the Y-Z plane seem to be considered for EFFL. Interestingly, if I display the Seidel Diagram of the two configurations for this last example, it gives the following:

Biconic Surface Seidel Diagram, Conf 1 (left), and Conf 2 (right)

Which again shows that the coefficients are only calculated correctly for configuration 2 (optical power in the Y-Z plane only).

Based on those results, on your current system, you’ll get the Y-Z data. If you make a second configuration of your system where you put the X-Z values into the Y-Z ones and vice versa (you sort of turn your system 90 degree about the optical axis), you’ll effectively get the X-Z data, if that makes sense.

Also, don’t forget there are the operands EFLX and EFLY which will give you the effective focal length in the corresponding X/Y-Z plane. For the NA, you could also use the Merit Function to calculate it in the X-Z plane.

Biconic Surface Merit Function showing EFFL, EFLX, EFLY, ISNA and custom NA calculation in X-Z plane (Sign in the comment of operand 18 should be SINE)

I hope this helps, and take care,

 

David

Reply