  We present an analytical description and an experimental realization of
interscale mixing microscopy, a diffraction-based imaging technique that is
capable of detecting wavelength/10 objects in far-field measurements with both
coherent and incoherent broadband light. This method aims at recovering the
spatial spectrum of light diffracted by a subwavelength object based on
far-field measurements of the interference created by the object and a finite
diffraction grating. A single measurement, analyzing the multiple diffraction
orders, is often sufficient to determine the parameters of the object. The
presented formalism opens the door for spectroscopy of nanoscale objects in the
far-field.
