Photosensitive glasses

Cheng, Y. Tsai, H. L. Sugioka, K. Midorikawa, K., Fabrication of 3D microoptical lenses in photosensitive glass using femtosecond laser micromachining, Appl. Phys. A. 2006, 85, 11 14... 

As was mentioned in Chapter 11., Section 6.6, photosensitive glasses contain small amounts of Au, Cu or Ag, i.e. elements which in the form of small crystals impart the glass a red (Au, Cu) or yellow (Ag) colour. Formation of these crystals is promoted by the effect of ultraviolet radiation. The practical significance of this phenomenon has considerably increased by the finding that the metal particles may serve as crystallization nuclei for non-metallic crij tals, i.e. the crystallization products of some silicate melts. The desired heterogeneous nucleation can take place when the secondarily precipitated crystals have crystalloehemica parameters similar to those of the metal nuclei. 

The Li20-Al203-Si02 system is the basis of some commercially important low thermal expansion glass ceramics, photosensitive glass ceramics, and higher thermal expansion glass ceramics that form seals with metals. The crystalline phases developed... 

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