Electro-optic half-wave voltages have been calculated for a longitudinal geometry in crystals of point group symmetry mm2 (orthorhombic) and 4mm (tetragonal). The predicted minimal longitudinal half-wave voltages range from 194 V in KNbO3, 100 V in Sr0,75Ba0,25Nb2O6 and 40 V in BaTiO3 to 9 V in KTa1-xNbxO3. The angular, wavelength and temperature dependences of the half-wave voltage have been determined. In KNbO3 measurements of the minimal longitudinal half-wave voltage at room temperature reached (195±8) V and (118±7 V) with red (λ=633 nm) and blue light (λ=458 nm) respectively. At -40°C, close to the orthorhombic-rombohedral phase transition, the half-wave voltage for red light reduces to (135±6) V. From the measurements we determine a negative sign of the electro-optic coefficient r42=-380 pm/V. The possibility of spatial light modulation by the longitudinal electro-optic effect is discussed.

Date Published: 31 January 1989
PDF: 6 pages
Proc. SPIE 1018, Electro-Optic and Magneto-Optic Materials, (31 January 1989); doi: 10.1117/12.949991

Published in SPIE Proceedings Vol. 1018:
Electro-Optic and Magneto-Optic Materials
Jean-Pierre Huignard, Editor(s)