Fast imaging of multimode transverse-spectral correlations for twin photons

Abstract

Hyperentangled photonic states -exhibiting nonclassical correlations in several degrees of freedom -offer improved performance of quantum optical communication and computation schemes. Experimentally, a hyperentanglement of transverse-wavevector and spectral modes can be obtained in a straightforward way with multimode parametric single-photon sources. Nevertheless, experimental characterization of such states remains challenging. Not only single-photon detection with high spatial resolution -a single-photon camera -is required, but also a suitable mode-converter to observe the spectral/temporal degree of freedom. We experimentally demonstrate a measurement of a full 4-dimensional transverse-wavevector-spectral correlations between pairs of photons produced in the non-collinear spontaneous parametric downconversion (SPDC). Utilization of a custom ultrafast single-photon camera lets us characterize the two-photon state with a high resolution and a relatively short measurement time.

Single-photon hologram of a zero-area pulse

“…The two ports are far-field imaged onto a mirror and a D-shaped mirror, respectively, allowing to separate the ports angularly, while imaging both on a single diffraction grating (1200 lines / mm, 750 nm blaze). The grating is farfield imaged on an ultra-fast intensified CMOS camera [32,33]. On the camera frame the ± ports appear as two separate regions of ca.…”