Transparent ceramics optical properties

Y, Shi, Q.W. Chen, J.L. Shi, Processing and scintillation properties of Eu doped LU2O3 transparent ceramics. Optical Materials, in press. (2008). 

Finally, the nature of the crystalline microstmcture, ie, crystal size and morphology and the textural relationship among the crystals and glass, is the key to many mechanical and optical properties, including transparency/opacity, strength and fracture toughness, and machinabiUty. These microstmctures can be quite complex and often are distinct from conventional ceramic microstmctures (6). 

In their ferroelectric state, the electro-optically useful PLZT compositions have an almost cubic structure, with the polar c axis being typically only about 1% longer than the a axes. Consequently the optical properties are almost isotropic and this, in part, is why high transparency can be achieved in the ceramic form. When an electric field is applied to the ceramic, domain alignment, or a field-enforced transition to the ferroelectric state, leads to the development of macroscopic polarization and so to uniaxial optical properties, i.e. the optic axis... 

The transmittance of the Nd (Yo9Lao.i)203 (a) and Nd Y203 (b) transparent ceramics is presented in Fig. 2. The highest transmittance of Nd (Yo.9Lao.i)203 reaches 80% which is 4-6 times that of Nd Y203. So the optical properties can be improved when doped La203. 

The optical properties of ceramics result in some of their most important applications. In their pure form, most dielectric single crystals and glasses are transparent to visible light. This behavior is very different from that of metals and semiconductors, which, unless they are very thin (<1 pm), are opaque. Many ceramics and glasses also show good transparency to infrared (IR) radiation. This property has led to the use of glasses for optical fibers for high-speed communications. 

Optical properties of Y2O3 ceramics, doped with rare-earth ions, are of special interest for some applications, such as solid-state lasers and scintillators [95]. Luminescence properties, such as upconversions, are also of special significance. For instance, REA"b co-doped Y2O3 transparent ceramics (RE = Er, Ho, Pr and Tm), exhibited very efficient NIR-visible upconverters [96]. 

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