My local surplus shoppe has a half dozen or so adjustable beam expanders. The scales are labeled 2-10x and they're coated for 1064nm. They're only $20 per so I'm interested enough that I plan on picking up 1 or 2 the next time I go there for some other bits-n-pieces but I was wondering if anyone here would know if the the 1064 coatings would work reasonably well for 532nm or whether I'd be wasting half of my photons. (PM me if you'd like me to snag one for you) Thanks!
Most of your photons would be lost. You can get an idea I think how much light would be lost by visiting http://www.edmundoptics.com/