We demonstrate experimentally the tunable control of the joint spectrum, i.e. waveform and degree of frequency correlations, of paired photons generated in spontaneous parametric downconversion. This control is mediated by the spatial shape of the pump beam in a type-I noncollinear configuration. We discuss the applicability of this technique to other sources of frequency entangled photons, such as electromagnetically induced Raman transitions.
@article{arxiv.0709.1810,
title = {Shaping the waveform of entangled photons},
author = {Alejandra Valencia and Alessandro Cerè and Xiaojuan Shi and Gabriel Molina-Terriza and Juan P. Torres},
journal= {arXiv preprint arXiv:0709.1810},
year = {2009}
}