  Diffraction limit is manifested in the loss of high spatial frequency
information that results from decay of evanescent waves. As a result,
conventional far-field optics yields no information about an object's
subwavelength features. Here we propose a novel approach to recovering
evanescent waves in the far field, thereby enabling subwavelength-resolved
imaging and spatial spectroscopy. Our approach relies on shifting the frequency
and the wave vector of near-field components via scattering on acoustic
phonons. This process effectively removes the spatial frequency cut-off for
unambiguous far field detection. This technique can be adapted for digital
holography, making it possible to perform phase-sensitive subwavelength
imaging. We discuss the implementation of such a system in the mid-IR and THz
bands, with possible extension to other spectral regions.
