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A bubblegram (also known as laser crystal, 3D crystal engraving or vitrography) is a solid block of glass or transparent plastic that has been exposed to laser beams to generate three-dimensional designs inside. The image is composed of many small points of fracture or other visible deformations and appears to float inside the block.
Each point is created by a laser beam focused to high intensity at that location by a computer-controlled opto-mechanical system. A complex or highly detailed image occupying a 5 cm (2 inch) cubic volume typically requires the creation of tens of thousands of such points.
Bubblegram images may be created by intersecting laser beams in appropriately doped plastic to induce a chemical reaction via heat or photonic excitation, creating bubbles or nodes where the plastic has a different index of refraction.
Glass block bubblegrams of Russian origin entered international commerce as a novelty in the late 1990s, but high prices and the predominantly simple, inartistic subject matter severely limited market penetration. In the early 2000s, a much less expensive, more visually appealing and highly diverse array of Chinese-made bubblegram novelties achieved wide commercial success in the United States, to the extent of becoming a fad: representations of monuments, corporate symbols, religious imagery, mythical creatures and nature scenes appeared in gift shops.
- "Laser-induced damage creates interior images", OE Reports, Number 191, November 1999 (via Internet Archive Wayback Machine). Retrieved 2013-02-16.
- Laser Crystal Technique How a single conical laser beam makes a bubblegram