Supercontinuum spectral-domain ghost imaging.

Ghost imaging is a technique that generates high-resolution images by correlating the intensity of two light beams, neither of which independently contains useful information about the shape of the object. Ghost imaging has been demonstrated in both the spatial and temporal domains, using incoherent classical light sources or entangled photon pairs. Here we exploit the recent progress in ultrafast real-time measurement techniques to demonstrate ultrafast, scan-free, ghost imaging in the frequency domain using a continuous spectrum from an incoherent supercontinuum light source with random spectral fluctuations. We demonstrate the application of this technique to broadband spectroscopic measurements of methane absorption performed with sub-nanometer resolution. Our results offer novel perspectives for remote sensing in low light conditions, or in spectral regions where sensitive detectors are lacking.