Light scattered by an object contains plethora information about the object which is distributed evenly among all possible Fourier components of light observed in the far-field. There are some cases, however, where this information is accumulated in the light confined by the object and then encoded in just a few coherent optical beams. Here, Fourier nanotransducers based on 2D plasmonic metamaterials are introduced, which are capable of confining light in 2D plane contacting with a functional interface, gathering information about its properties, and then transmitting the information into discrete optical beams with amplified phase relations. It is shown that phase of light in such beams can be used for probing dynamic physical properties of 2D materials and performing bio/chemical sensing with unprecedented sensitivity. Using a Fourier transducer based on periodic gold nanostructures, ferroelectric response from a single atomic layer of MoS
is resolved and studied for the first time, as well as the detection of important antibiotic chloramphenicol at fg mL
level is demonstrated, which several orders of magnitude better than reported in the literature. The implementation of phase-responsive Fourier nanotransducers opens new avenues in exploration of emergent 2D structures and radical improvement of biosensing technology.