BIREFRINGENCE IMAGES OF SCREW DISLOCATIONS VIEWED END-ON IN GGG AND YAG CRYSTALS
直拉法生长的GGG和YAG单晶体中螺型位错的双折射像

Birefringence images of screw dislocations in Gadolinium Gallium Garnet (GGG) and Yttrium Aluminum Garnet YAG) crystals are studied in detail. Birefringence images of screw dislocations viewed end-on were observed for the first tiane. The one-to-one correspondence between birefringence images of screw dislocations viewed end-on and that viewed from the side was demonstrated. The contour of equal intensity of birefringence image of screw dislocation viewed end-on in GGG and YAG crystals was derived by considering the photo-elastieal anisotropy of garnet, and the result yields good agreement Avith experimental observations.