Hi all, I've been toying with an idea lately and I'm wondering if any of you could help me out. Is there any method you know of to heat an area roughly 5 nm in diameter? I've thought about laser radiation for a while, but of course we are limited by wavelength. 5 nm would force us into the x-ray or gamma range, so I still don't know if that's possible. I've never heard of a beam width that was 5 nm either, I assume that's borderline impossible to do in space (maybe in a fiber optic cable it would be doable? I do not know.) I know certain optical lithography techniques can create features with resolution a fraction of wavelength, but my understanding was most of them still produced things on the order of >45 nm. I've heard things about electron beam lithography. That seemed at least possible (but that brings us to the next problem, it seems very very expensive and not terrible feasible.) Something with a radial temperature gradient could work. If a central area (5 nm in diameter) was notably hotter than the next ring out (say, 5-10nm diameter) then that might work, as there is a threshold I'm dealing with here and it does not matter if external regions are lower than it. Any ideas? Maybe something chemical... I'm not sure. All suggestions and musings are very welcome and appreciated. Thanks for your help, C.