FROM: aes SUBJECT: Re: 3 Dimensional Glass Bubble Figures Inside Optical Glass Cubes DATE: Sun, 10 Feb 2002 11:22:31 -0800 ORGANIZATION: Stanford University NEWSGROUPS: sci.optics In article <3C66463E.89A6C13C@ecs.soton.ac.uk>, "H.N.Rutt" wrote: > Sam Goldwasser wrote: > > > cameron@west-point.org (cameron price) writes: > > > > > Recently,in a gift shop,I saw small cubes of what was described as > > > optical glass, maybe an inch on a side. Inside these cubes were > > > sharks, a motorcycle, a dog...all defined by what appeared to be small > > > bubbles. In full 3 dimensions. Even the spokes and control cables on > > > the bike were well defined. > > > > > > A man in the store said it was the result of, only recently released, > > > secret Russian technology. The bubbles were crystal clear, but I was > > > told there may be a color component as well. Supposedly generated by > > > lasers off a computer data base of the object surfaces. > > > > Probably a focused pulsed YAG laser with position and focus under computer > > control. Nothing particularly secret or only Russian about it as far as I > > know. :) > > Um; that was my first thought but the writer said: > "The bubbles were crystal clear, but I was......" > That does not correspond to the internal damage spots Ive seen which generally > look frosted & not like clear bubbles. Also they tend to be asymmetric, > extending at least a bit in the beam direction. > "In full 3 dimensions. Even the spokes and control cables on the bike were > well defined." > Perhaps theyve chosen a glass with especially favourable characteristics & > used a very short focal length... but thats limited by the thickness of the > item. I guess you would want a negative n2? > > Maybe it is a simple focussed YAG or whatever, just somethiong a bit trickier. > > Harvey The basic process is a.k.a. "bulk (or internal) optical damage" produced by a focused laser beam. The basic effects were observed with the very earliest ruby and other pulsed lasers in the early 1960s, very often unintentionally and to the detriment of expensive optical components including sometimes the laser rods themselves. This led to a whole field of "laser damage" studies, including a series of NIST-sponsored symposia and other publications over the next several decades, and quite a lot of early work in the Soviet Union also.. The physical process involves a complex mixture of photoionization, multiphoton ionization, melting, vaporization, and various stimulated scattering processes, leading to bubble formation, track formation, and "micro-explosions" occuring at either the focal spot or at various intrinsic defects inside the material. The exact details of what happens depend on the wavelength, intensity, and pulse duration of the laser pulse and the physical characteristics of the material. There are a number of small firms in the U.S. and elsewhere who will write the kind of decorative cubes you saw in the gift show, in glass or plastic cubes, using computer-controlled pulsed YAG or other lasers. They will also fabricate inexpensive customized versions as mementos for going-away parties, bowling trophies, and so forth. There is also a recent (late 1990s) patent by a British guy on a subsurface marking apparatus of this sort which has been used by a major distillery for writing subsurface serial numbers into the bottoms of zillions of Scotch whiskey bottles. I'll not provide a citation because IMHO given the prior art and state of knowledge of these effects the patent should never have been issued. FROM: "beric" SUBJECT: Re: 3 Dimensional Glass Bubble Figures Inside Optical Glass Cubes DATE: Sun, 10 Feb 2002 20:39:16 -0000 ORGANIZATION: ntl Cablemodem News Service NEWSGROUPS: sci.optics Its actually British Technology, but as usual developed overseas. Patent is owned by United Distillars. They are micro cracks, that are laser written into the glass. In the UK you can get them from www.artinglass.co.uk Beric cameron price wrote in message news:c843fe2d.0202091625.be47c18@posting.google.com... > Recently,in a gift shop,I saw small cubes of what was described as > optical glass, maybe an inch on a side. Inside these cubes were > sharks, a motorcycle, a dog...all defined by what appeared to be small > bubbles. In full 3 dimensions. Even the spokes and control cables on > the bike were well defined. > > A man in the store said it was the result of, only recently released, > secret Russian technology. The bubbles were crystal clear, but I was > told there may be a color component as well. Supposedly generated by > lasers off a computer data base of the object surfaces. > > Anyone know more? > > Cameron FROM: dulmage@visi.com (Doug Dulmage) SUBJECT: Re: 3 Dimensional Glass Bubble Figures Inside Optical Glass Cubes DATE: Tue, 12 Feb 2002 14:20:57 GMT NEWSGROUPS: sci.optics In article <6w7kpmi2of.fsf@saul.cis.upenn.edu>, Sam Goldwasser wrote: >Probably a focused pulsed YAG laser with position and focus under computer >control. Nothing particularly secret or only Russian about it as far as I >know. :) Actually, when I first started digging into these things as I wanted to try doing my own, I did find that there was a difference between items made in the US vs the Russian items. There is a web site somewhere that gives some fairly good detail on the Russian process, and they do detail that the glass they use is doped with something, they don't indicate exactly what the doping does, but I suspect it might lower the threshold for the fractures, etc. The units from the two countries def. look different as far as the glass is concerned. I.e. the Russian units appear to have a bit of a pink cast to it. So, who knows, could be urban legend, or it could be correct info. Doug