Specialty Optical Fibers Handbook

21.5 APPENDIX: MATERIAL PROPERTIES OF Al

2

O

3

The data in Table 21.1 are taken from the Handbook of Optical Materials by

Marvin J. Weber [48], except where indicated.

Aluminum Oxide, Al

2

O

3

, is an insulator known variously as sapphire, corun-

dum, and alumina. This uniaxial crystal belongs to the trigonal crystal system and

space group R-3c. The extraordinary ray, e, is polarized parallel to the c-axis, the

axis of anisotropy, and the ordinary ray, o, is polarized perpendicular to the c-axis.

Table 21.1

Material properties of Al

2

O

3

Material property Value(s)

Transmission Window

a

(mm) 0.19–5.2

Band gap (eV) 9.9

Refractive index at 632.8 nm, extraordinary

b

(n ...