Study on defects in Nd: YAG crystals by darkfield and phase contrast microscopy

The resolution of darkfield and phase contrast microscopy is up to 10 approximately 500 Angstrom. The fine structure of point defect clusters, small size dislocation loops and helical dislocation in Nd:YAG crystals can be observed very clearly by these techniques, especially, the image of the undecorated edge dislocations and mixed dislocations in crystals have also been got from them. The observation of undecorated dislocations was confirmed by chemical etching optical birefringence and X-ray topography.