Optical Properties of a Piezoelectric Ta2O5 Single Crystal Film

Following the production of a uniaxially oriented Ta2O5 thin film on a single crystal substrate (X-cut LiTaO3) by RF sputtering, a Ta2O5 single-crystal film was created using linear rapid thermal annealing. Then the reflection high-energy electron diffraction (RHEED) pattern and X-ray diffraction pattern of the Ta2O5 single-crystal film were measured to examine its crystallization level. A refractive index tensor was obtained using the m-line technique and by measuring the Brewster angles of the film. Results showed clearly that the resultant single crystal film ws mostly composed of optically anisotropic crystals. In order to obtain the photo elastic constant of the thin film, we measured Raman–Nath diffracted light intensities for both Ta2O5 and Ta2O5/LiTaO3. From these results, the photo elastic constant of the thin film was about 6–10 times greater than that of LiTaO3.