Quantum Ghost Imaging Spectrometer

We present a device that exploits spatial and spectral correlations in parametric down-conversion at once. By using a ghost imaging arrangement, we were able to remotely reconstruct the frequency profile of a composite system. Our device can detect the presence of distinct spatial regions, each of them characterized by different spectral absorption. This is enabled by a model-independent analysis, making it possible to identify the spectral component based uniquely on the collected data and without recurring to a priori information. Such an approach can be beneficial in the low-count regime, which is a typical condition in these experiments