There is no dust in the mirror. The resonant cavity is near perfectly sealed. Otherwise it wouldn't work. And what we measure is it's luminosity, and it's very easy to do.
There is my step-by-step guide:
1º Post my idea on the forum
2º Get some FE'rs support, so the experiment would be worthy. All I need is that FE'rs say "Oh! Ideally, it will work as a BL detector!". Remember that i'm talking about the idea, none math is done here. WE ARE AT THIS STAGE
3º I'll go to the lab, gather some info about the laser I'll use and post some photos of it, wich clearly shows the model etc etc.
4º I'll do the math, I'll calculate the expeted "bright loss" with BL. If it is detectable with my photometre I'll move to step 5.
5º I'll go to the lab and make the experiment.
6º With the data on my hand I'll tell you if BL does exist or not.
Notice that steps 3-6 need some effort. I'll only move to step 3 if it's worth. So, Mizzle, do you think that there would be any "bright loss" when rotating the laser due to BL as I stated before (remember, I'm not talking about measuring it, i'm only talking about the idea)? Parsec said yes, what do you think about my experiment?