POLARIZATION DIRECTIONS OF NONCOLLINEAR PHASE-MATCHED OPTICAL PARAMETRIC DOWNCONVERSION OUTPUT

An analysis of the output polarization of a noncollinear type I optica l parametric downconversion source is presented. Such a source can be made by pumping a nonlinear crystal with an extraordinary-polarized be am to produce pairs of ordinary-polarized photons. A polarization map of the output light illustrates dramatic variation in the polarization direction at large scattering angles. The effect of this variation in polarization direction is seen on a map of the nonlinear conversion e fficiency. The apparent ambiguity in the polarization for the particul ar case in which one of the outputs propagates along the crystal optic axis is also discussed. (C) 1997 Optical Society of America.