Low light detectors, for example those used in cameras only operate at certain frequencies / wavelengths. Outside of these wavelengths they become inefficient and for certain wavelengths commercial available detectors may not function at all. However the material properties or dimensions of the item to be imaged dictate the optimal wavelength.
An imagining method co-developed at the Faculty of Physics of the University of Vienna and the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences solves this issue by using quantum entanglement to separate the wavelengths used for illuminating from the detection.