Analysis of accuracy of measurement of quadratic electro-optic coefficients in uniaxial crystals: a case study of KDP

摘要

Taking KDP as an example of a uniaxial crystal, we analyze contributions to its quadratic electro-optic response with a view to explaining differences in published values of certain quadratic coefficients. In an eigenvalue theory of light propagation we show that the linear electro-optic coefficient contributes to the quadratic response, even under ideal laboratory conditions. In addition, the effect of imperfect crystal cutting and alignment is investigated by means of computer calculations based on the Jones calculus. It is found that, for relatively small inaccuracies, the calculated values of the quadratic coefficient g_(xyxy) are approximately two orders of magnitude greater when measured with a statie field than with a dynamic one. This finding could explain the observed spread in some results for KDP-type crystals.