The mechanism by which a beam splitter operates is based on the principles of partial reflection and partial transmission. 📦 For purchasing, use the RP Photonics Buyer's Guide for beam splitters. To fully understand how beam splitters work, it is important to delve into their operational. Beamsplitters are optical devices able to either split an incident light beam into two separate beams or combine two incoming beams from distinct angles into a single output.