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Frontiers in Optics

Observation of Elliptical Patterns in Type I Spontaneous Parametric Down Conversion

Hannah E. Guilbert, Daniel J. Gauthier, Yu-Po Wong

Published Jan 1, 2013• 0 citations
Publisher

Abstract

We measure the spatial profile of down-converted light from Type-I SPDC in BBO and BiBO crystals. We find BiBO (BBO) produces elliptical (circular) transverse patterns because the generated light experiences an angle-dependent (-independent) refractive index.
DOI
10.1364/ls.2013.lw2g.5

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We report on the use of elliptical pump spatial modes to increase the observed brightness of spontaneous parametric downconversion in critically phase-matched crystals. Simulations qualitatively predict this improvement, which depends on the eccentricity and orientation of the pump ellipse. We experimentally confirm a factor of two improvement in brightness when compared to the traditional circular-symmetric pump spatial modes. These results support previous theoretical work that proposes the use of elliptical pump modes to enhance the performance of parametric processes in anisotropic materials.
In this paper, we report on the collinear spontaneous parametric down conversion (SPDC) with quantum theory in angle picture. Based on angle-dependent refractive index of biaxial crystal and the dielectric dispersion, we numerically simulate the effective nonlinear coefficients of BiB 3 O 6 (BIBO) crystal in principle planes. The results indicate that the most effective phase matching scheme is the type I in yz plane, while the secondary options are the type I, type II in xz plane. Considering the derivation of angular phase matching conditions, the calculation is convenient, and it is superior in determination of the spatial distribution of entangled photons.
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