Hydrothermal synthesis of single-crystalline one dimensional β-BaB2O4 microrods with second order nonlinear optical properties

The second harmonic generation (SHG) have been the most extensively used and well understood nonlinear optics phenomenon. It implies a generation of new output frequency, twice larger than that of the incident laser radiation. Therefore, it is of key importance to propose appropriate second harmonic generation media. To date, the one-dimensional inorganic nanostructures are expected to exhibit a strong nonlinear optical response. Herein, we fabricated single-crystalline one-dimensional β-BaB2O4 microrods via a facile hydrothermal procedure and subsequent annealing using barium chloride, sodium borate and hydrochloric acid as starting materials. The fabricated β-BaB2O4 microrods generated good spectral response within the excitation range of 800-1064 nm. The SH intensity of the microrods increased linearly with excitation intensity I (In, n = 2.11), which demonstrated the quasi two-photon dependence. These results reveal that the fabricated β-BaB2O4 microrods are promising for future nonlinear optical applications.