Photonic barrier doesn't seem to be a widely standardized or accepted term. The closest to what you're referring to seems to be something to attenuate effect of

Photonic barrier doesn't seem to be a widely standardized or accepted term. The closest to what you're referring to seems to be something to attenuate effect of light on night vision equipment. But back on topic: light cannot block light. First result on google. https://physics.stackexchange.com/questions/456409/can-a-light-block-reduce-another-light-if-projected-in-exact-opposite-direction https://physics.stackexchange.com/questions/456409/can-a-lig.... Though I'll concede you a point in that, if their pupils are contracted more because they're using a brighter source, then the impact of your beam on them will be lower than theirs on you. That being said, I'd wager to say that the difference would probably be marginal, given that we're talking about light reflected at night (which would leave you with a pretty big dilation in both LED and halogen) vs. looking directly at a light source.