PIEZO-OPTICAL PROPERTIES OF GE

The piezo-optical properties of Ge, for pressure along the [001] and [ 111] directions, are calculated with the use of a realistic empirical tight-binding model. The real and imaginary part of components P-11(om ega), P-12(omega), and P-44(omega) Of the linear piezo-optical tensor for Ge are evaluated. The main structures in P-ij are located around t he E-1 and E-2 critical points. Deformation potential constants D-1(1) , D-1(5), D-3(3), and D-3(5), for the E-1-(E-1+Delta(1)) transitions a re also evaluated. The theoretically obtained results are in good agre ement with existing experimental values.