Hello, I am wondering how does a reflection diffraction grating work. Most physics text simply ignore this topic or talk in very ambigious terms. I understand that in transmission diffraction grating, you have parallel grooves so that light can pass through and produce an interference pattern. How does a reflection diffraction work? Do you still have open silts? Or is light is divided in half by making the diffraction grating material reflective? i.e. half of the pass throguh the open silts while the others hit the non-open parts and get reflected back? The problem with that is light is not diffracted though since it does not pass through a narrow opening. Thanks for any help.