Processing of incoherent electromagnetic radiation is described, said incoming incoherent electromagnetic radiation comprising radiation in a first wavelength interval. An arrangement comprises a focusing arrangement for focusing the incoming incoherent electromagnetic radiation, a first cavity configured to comprise an intra cavity laser beam, a nonlinear crystal arranged in the first cavity such that it is capable of receiving the focused incoherent electromagnetic radiation and, in dependence on the spatial overlap between the focused incoherent electromagnetic radiation and the intra-cavity laser beam, by interaction with the intra-cavity laser beam provide processed electromagnetic radiation, said processed electromagnetic radiation comprising radiation in a second wavelength interval. In other words, such an arrangement is capable of enabling imaging, e.g. by utilizing a detector that is sensitive in the second wavelength interval, a source of radiation that emits incoherently in a first wavelength interval.