Measurement of the electro-optic coefficients: description and comparison of the experimental techniques
This paper presents a review of experimental methods used to determine electro-optic (EO) coefficients in bulk materials. The techniques are based on the relations describing the electro-optic effect in one-beam-ellipsometric or two-beam-interferometric optical arrangements. The methods are classified according to the nature (dc or ac) of the electric field applied onto the sample (static or dynamic methods) and with respect of the measured physical quantity (voltage, phase retardation, light beam intensity, etc.). Theoretical analysis and considerations of practical interest are presented in the article with particular attention paid to the resulting error in the determination of the EO coefficient associated with each method. A complete analysis of advantages and drawbacks of methods is finally given as a function of different experimental parameters such as the accuracy or sensitivity, the complexity of the implementation, the signal and the physical quantity used to derive the EO coefficient. Measurements of the coefficient rc as obtained by means of the various methods on the same congruent crystal of LiNbO3, are used to support the comparison between techniques.