Patent ID: 7388668

Claim:
A system for detecting a non-linear coherent field induced in a sample volume, said system comprising: a first source for generating a first electromagnetic field at a first frequency; a second source for generating a second electromagnetic field at a second frequency; first optics for directing a first portion of said first electromagnetic field and a first portion of said second electromagnetic field toward the sample volume; second optics for directing a second portion of said first electromagnetic field and a second portion of said second electromagnetic field toward a local oscillator volume; third optics for combining a first scattering field that is generated by the interaction of the first portion of the first electromagnetic field and the first portion of the second electromagnetic field in the sample volume, with a second scattering field that is generated by the interaction of the second portion of the first electromagnetic field and the second portion of the second electromagnetic field in the local oscillator volume; and a detector system for determining at least one of a real component and an imaginary component of the first scattering field responsive to the first and second scattering fields, wherein said sample volume and said local oscillator volume are positioned in optical paths that are functionally in series with one another.