Fig. 1.

Sketch of the proposed quantum imaging setup. A broadband pump pulse with the wavevector ${\mathit{k}}_p$ propagates through a ${\chi }^{\left(2\right)}$ crystal, generating an entangled photon pair denoted as signal and idler. The photons are distinguished either by polarization (type II) or by frequency (type I) and are separated by a beam splitter (BS). The signal photon interacts with the sample and can be further frequency dispersed and collected by a “bucket” detector $D_s$ with no spatial resolution. The idler is spatially resolved in the transverse plane by the detector $D_i$. The two photons are detected in coincidence (Eq. 12).