Domain switching by femtosecond NIR laser irradiation in bulk of single-domain and polydomain SBN single crystals

We have studied features of the domain patterns formed under the action of femtosecond near-infrared laser irradiation in the bulk of strontium barium niobate Sr 0.61 Ba 0.39 Nb 2 O 6 single crystalline Z-cut plates in single-domain and polydomain states. The polydomain state represented nano-scale maze domain structure in non-ergodic state created by zero-field cooling from paraelectric phase. In single-domain sample the domain consisted of the narrow spindle-like and the lens-like parts, whereas in polydomain sample the four times shorter spindle-like domains were formed. The unusual shape and length of domains produced in single-domain samples was attributed to the additional input of the switching field produced by photoinduced space-charges which is enough for domain formation. These charges appeared as a result of multiphoton absorption and localized at the boundaries of the lens-like area. The absence of the lens-like domain part for irradiation of the polydomain sample is attributed to the absence of the photoinduced space-charges field due to lack of macroscopic polar axis. It was shown that the action of the photoinduced space-charge field leads to four-times increase of the length of created domains. The revealed mechanism of the domain growth in the crystal bulk by space-charge field induced by multiphoton absorption should be taken into account for manufacturing of 2D and 3D nonlinear photonic crystals in ferroelectrics with comparatively low threshold values of the switching fields.