Hello John,

I don't know if you have seen it but we have a learning path on Illumination Systems: https://www.zemax.com/blogs/free-tutorials/illumination-systems-fundamentals. It is in the knowledgebase article section.

In this path, there is an article called How to optimize non-sequential optical systems.

Let us know if that helps and do not hesitate if you have any further questions.

Sandrine

Hi Sandrine,

Thank you for your reply. I have already looked through the materials you have refreed to and unless I am misunderstanding something, I'm not finding what I need.

 On the assumption that I should be using a polar detector and using the NSDP operand, what should I set the Pix# parameter to? I would like to maximise the power going into a ring at 90 degrees. -1,-2,-3 don't seem right. -4 says it is referenced to 0 degrees- not what I want.

Perhaps I need a cylindrical detector?  Can I create a cylindrical detector surface and use the NSDD operand? I've tried creating a cylindrical pipe object, but it won't let me set 'object is a detector'

John

Hi John, 

My experience has been that using a large area detector for a specific target, in this case, a specific angle of 90 degrees, may not work well. We end up with many empty pixels that don't provide any function. In my previous experience, I sometimes used small tiles and tiles of detector rectangles in the shape of a pseudo-hemisphere because I needed the resulting data in a specific format. I think something similar is needed here. 

My advice would be close to your own suggestion, use a different detector but try to shape it so that the range is very small. For example, although the cylindrical object set to a detector may not work here, you can make a very slim and long rectangular object and set it far away from your source. Let's say the height of the rectangle is equal to the range from 89 to 91 degrees. We can set this rectangular detector far from the lens, and optimize for maximum flux (or intensity). I think the symmetry in your system may be beneficial that this can work. We can set multiple detectors for optimization as well, so don't be shy about using, say six long-but-thin detector rectangles and use them around your lens (partially), and optimize for all to be maximum flux. 

-Kats

Hi Kats,

Thank you for your suggestions. I think this is the way forward. I guess I may need to nest or overlap some detectors with graded weights on the optimization operands in order to guide the pattern in the right direction. I'll give this a try. I'll leave the polar detector for visualisation and presentation purposes.

John

I think Kat has a great idea. (As usual)

If the system has axial symmetry, then you shouldn't need to cover the entire circumferance. It should be sufficient to use one detector on axis and one on the side. The merit function targets zero power to the on axis detector to direct power to the side. The merit function targets full power to the side detector with small SpotY (or X depending on orientation) and a Ycentroid at the center. Hopefully, if the initial design puts some power on the side detector, the gradient will tend toward what we want. 

Hi sorry to jump in here, but I might have a similar question to John. 

My system is a two prism system in Risley configuration:

I need to find the exact prisms orientation in order to redirect light straight at the exit. I numerically calculated them, but ray trace tells me I am slightly off.

In order to check it, I am using a polar detector and my goal is to have theta=0. How should be the merit function? 

I have first tried by placing two irises along the optical path and a rectangular detector, forcing the power here to be higher than the one I record at 0 incident field, didn’t work out.

Thank you for your help,

best,

Giulia.