We report, to our knowledge, the first polarization-resolved measurement of the frequency dependence of both the electronic and the electrostrictive contributions to the dc Kerr coefficient in silica. At the acoustic resonance the perpendicular polarization phase shift is a factor of 2.3 times greater than in the parallel polarization, confirming the presence of strong electrostriction. We find good agreement between the phase-shift measurements and theoretical models of both the polarization and frequency dependence. The analysis indicates the dc Kerr coefficient χ<sub>1111</sub><sup>(3)</sup>(−ω;ω, 0, 0) to be 1.9 × 10<sup>−22</sup> m<sup>2</sup>/V<sup>2</sup>. From these results the electrostrictive contribution to a poled-silica device near the device acoustic resonance is expected to be r<sub>33,Es</sub> = 28 pm/V, over an order of magnitude greater than the electronic Kerr electro-optic coefficient r<sub>33, Kerr</sub>=0.2 pm/V.
© 2001 Optical Society of America
(160.2750) Materials : Glass and other amorphous materials
(160.6030) Materials : Silica
(190.0190) Nonlinear optics : Nonlinear optics
(190.3270) Nonlinear optics : Kerr effect
(230.2090) Optical devices : Electro-optical devices
Alice C. Liu, Michel J. F. Digonnet, and Gordon S. Kino, "Measurement of the dc Kerr and electrostrictive phase modulation in silica," J. Opt. Soc. Am. B 18, 187-194 (2001)