Periodic domain walls and ferroelastic bubbles in neodymium pentaphosphate

Abstract
The first observation of accurately periodic ferroelastic domains in neodymium pentaphosphate (NPP) is reported. A description is given of the nucleation process of these periodic domains in terms of a newly discovered phenomena of ferroelastic bubbles. These periodic arrays have been shown to be tunable from 70 to less than 0.5 μm. Device applications of these arrays as tunable active optical Bragg gratings and acoustic filters are discussed.