|MadSci Network: Physics|
Hello, Julian. Interesting question – I hadn’t thought of it before you asked. In principle, there is no reason why one couldn’t make a UV laser sight. In practice, however, there are two big problems: 1) the lasers and 2) the optics. The kinds of lasers you’d need (small, bright, yet low-powered and electrically driven) are only now coming on the market. That means that they’re too expensive, too short-lived, and likely have too poor a beam quality to make a good laser sight. We can imagine, however, a time in the near future in which they’re easily available. Even then there may not be any UV laser sights. A big problem with a UV laser sight would be viewing a focused image of both the laser spot and the target at the same time. Whether you’re looking at something with your naked eye, through a scope, or using a camera, the image you see is brought into focus through different optical materials – usually lenses. The problem is that UV light is going to focus much differently through these lenses than any other kind of light. So, unless you spend an awful lot of money (and size & weight) on designing a UV-corrected imaging system, you won’t be able to view the laser spot as a small, focused object on your target … which kind of defeats the purpose. I can tell you how large this effect can be from personal experience. I remember the first time I walked into a lab that had optical fibers transporting very blue laser light. Since I could dimly see the blue color, it wasn’t even truly UV light. From the doorway it looked like the fibers were about 1/2 an inch in diameter. When I walked up to the fiber, however, I saw that it was the size of any other bare optical fiber: not much thicker than a human hair. What made it appear so thick from 15 feet away was the inability of my eye to focus light that blue, when everything else from that distance was in focus. So, there you have it. A UV laser sight wouldn’t be impossible to make or use. It would, however, be very expensive and complicated. There would have to be a very compelling reason to use UV light in order to justify the expense. Note: I didn’t put in a link to any UV laser company, since such a site wouldn’t really be an educational one. If you really want to know what’s available, however, you can always do an internet search on “blue laser” or “blue diode laser” … diode lasers are the small, electrically-driven lasers that you have in CD/DVD players, and would be the best choice for a laser sight.
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