OPTICAL PROPERTIES IN CRYSTALS 



181 



VI. Electro-optic and Photoelastic Tensors for Various 

 Crystal Classes 



Since r,„„o = r,„„„ and 2:,„„„ = Znmo are third rank tensors similar to the 

 //„, ij piezoelectric tensor, they will have the same components for the various 

 ( rystal classes. For the twenty crystal classes that show the electro-optic 

 effect these tensors are given below. They are given with the crystal system 

 they belong to, and the symmetry is designated by the Hermann-Mauguin 

 symbol. The last number of the subscript of z designates the direction of the 

 applied static field. 



(91) 



Trichnic; 1 



Monoclinic; 2 



Monoclinic; 2 = m 



( )rthorhombic; 222 



' Orthorhomic; 2mm 



'I'etragonal; 4 



