Pockels Effect


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Pockels effect

[′päk·əlz i‚fekt]
(optics)
Changes in the refractive properties of certain crystals in an applied electric field, which are proportional to the first power of the electric field strength.

Pockels Effect

 

(also electrooptical effect), the change in the index of refraction of light in crystals placed in an electric field, the change being proportional to the intensity of the field. The effect is observed only in piezoelectric materials. It was first discovered in 1894 by the German physicist F. C. Pockels but for a long time thereafter was little studied and found limited application. This was due chiefly to the high voltages—on the order of hundreds of kilovolts—needed to obtain an appreciable effect.

The emergence of lasers stimulated the study of the Pockels effect, which in turn has been used in the development of a number of devices for controlling coherent optical radiation electrically. Almost all light modulators are based on the Pockels effect. It has the important property of low inertia, which permits light to be modulated up to frequencies of approximately 1013 hertz. Moreover, because of the linear dependence of the refractive index on the intensity of the electric field, the nonlinear distortion incurred in modulating light is fairly low. The low inertia allows the use of the effect in modulating the quality factor of lasers and thus obtaining light pulses of short duration and high power. The effect is also used in systems that deflect light beams and in devices that produce two-dimensional optical images.

REFERENCES

Sonin, A. S., and A. S. Vasilevskaia. Elektroopticheskie kristally. Moscow, 1971.
Mustel’, E. R., and V. N. Parygin. Melody moduliatsii i skanirovaniia sveta. Moscow, 1970.

V. N. PARYGIN

References in periodicals archive ?
Tulli et al., "Electro-optical modulation based on Pockels effect in BaTiO3 with a multidomain structure," IEEE Photonics Technology Letters, vol.
The THz beam modifies the index ellipsoid of the ZnTe crystal transiently via the Pockels Effect. The linearly polarized probe beam copropagates inside the crystal with THz beam, and its phase is modulated by the refractive index change induced by the electric field of THz pulses.
A physicochemical property much more affected by the structural features is the electronic first-order hyperpolarizability ([beta]) and the related nonlinear optical (NLO) properties Second Harmonic Generation (SHG) and Electro-Optical Pockels Effect (EOPE) [17-32].
The NCVIT is based on the electro-optic Pockels effect that produces birefringence in an optical medium induced by a constant or varying electric field.
The resulting space-charge field modulates the index of refraction of the photorefractive recording material (such as [LiNbO.sub.3], or lithium niobate) due to Pockels effect, or the change in index of refraction under an applied electric field.
The linear electro-optic effect or Pockels effect is capable of 100 GHz modulation because it is a field effect that distorts electron clouds in the solid.