Terahertz spectroscopic study of cerium oxide thin film

Dynamic optical behaviour of CeO₂ thin film has been investigated using terahertz spectroscopy at room temperature by exciting with different amplitude pulses. The CeO₂ thin film has been deposited on Si (100) substrate by RF magnetron sputtering technique. It has been observed that the optical density increases at 0.75 THz on the incident of pulse beyond 100kV/cm. This indicates that direct excitation of CeO₂ vibrations with intense THz pulse can induce extremely large amplitude motions in the harmonic potential of the material. This study shows that it is possible to control the large amplitude motions in the materials using different high power THz pulses, and in turn can control the optical properties, establishing the nonlinear spectroscopy technique for such studies. (author)