Hi all, I'm new to this forum and not sure if this is the right place to post this question. I know that beamsplitters normally have dielectric coating on one side and AR coating on the other side. I'm looking at this plate beamsplitter specifically: https://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=4808 I want to know what would happen if light is incident inversely, eg, it hits AR coating first then the dielectric coating. Will I get part of the light going downwards and the rest going through the beamsplitter? Basically I'm looking for a beamsplitter that only allows on-way transmission. Any help is greatly appreciated!