Alec, it might possibly, but the setup would be ungainly and still be subject to incident reflection and emission, I rank it a few notches higher than the collimator for practicality but I certainly won't try to implement that one knowing what I know now. I'm pretty much resigned to eventually purchasing a close focus non contact meter, but the information I'm getting by looking into this is priceless to someone as purely curious about physical materials as I am.
I mean really, of all the materials you'd think of, Glass, Quartz, Zinc Sulfide, Silicon, Germanium, HDPE. Seriously, who would start off the bat thinking that one of the most common industrial plastics on the planet can be used for focusing far infrared!