Hi Yang,

In sequential mode, a ray cannot “skip” a surface so you cannot simply have a single configuration with a 500nm band pass filter that is decentered.  However, you can split your image plane into 2 halves with multi-configs, use a TABLE coating to create a cutoff filter and then use a number of paired down analysis which can merge the 2 configurations back together (Spot Diagram, Footprint Diagram, Geometric Image Analysis, Huygens PSF, Huygens MTF).

However, the better approach would be to create a User Defined Surface and leverage the UD->rel_surf_tran property.  In the User Data structure, you have access to the ray’s XY coordinates (UD->x and UD->y) and in the Fixed Data structure, you have access to the ray’s wavelength (FD->wavelength).  So the pseudo code in case 5 of the UDS would look something like this:

case 5:
   if (UD->y >= 0.0 && FD->wavelength >= 0.5)
   { UD->rel_surf_trans = 0.0; }

   if (FD->cv == 0.0){
      if (Refract(FD->n1, FD->n2, &UD->l, &UD->m, &UD->n, UD->ln, UD->mn, UD->>)) return(-FD->surf);
   } else {
      /* not a plane, copy code from UDS example for snell’s law refracting */

   }
   break;

There are 8 different UDS filter examples in the Zemax\DLL\Surfaces folder that can help you get started.

P.S. If you can use non-sequential, I would suggest doing that.  This is a trivial problem in non-sequential mode.

Hi Michael

 Thanks for your reply. I think the User Defined Surface can make it.

I will have a try

 Thanks again!

Yang

case 5:
   if (UD->y >= 0.0 && FD->wavelength >= 0.5)
   { UD->rel_surf_trans = 0.0; }

   if (FD->cv == 0.0){
      if (Refract(FD->n1, FD->n2, &UD->l, &UD->m, &UD->n, UD->ln, UD->mn, UD->>)) return(-FD->surf);
   } else {
      /* not a plane, copy code from UDS example for snell’s law refracting */

   }
   break;

Hi Michael and zemaxers,

 I have tried the UDS but got the result not as I thought

y>=0 && wave >=0.5   rel_surf_tran =0

there shall be no spot in red rectangle area of the pic below, right?

I am just wondering where I am wrong .

Would you please have a check with my file?

Thanks

Yang