Please Provide me with some help in DUAL-GRIDDED REFLECTOR!!

I need some help in DUAL-GRIDDED REFLECTOR. But it is very difficult as for the coodinate translation and thin strip grating. The softwares I get are TICRA GRASP8 and POS4. There are some examples in the manual, however no one is very detailed. Can you give me some examples or references? Or introduce me some books and thesis?

Thank you very much!

here a good exp.

pl

Thank you!