An improved system for sensing includes a first signal source for producing an excitation signal for exciting a specimen having a nuclear quadrupole resonance, a signal sampling device for sampling a response signal received from the specimen to produce a plurality of samples, a data storage device for storing a plurality of data corresponding to said plurality of samples; and a processor for time coherently processing the plurality of data to sense the nuclear quadrupole resonance of said specimen. An optional second signal source for producing a probe signal directed at the specimen can also be used, where the response signal corresponds to the probe signal having reflected off the specimen.