We present an extension of the two-point optical microrheology techniqueintroduced by Crocker \textit{et al.} [Phys. Rev. Lett. \textbf{85}, 888(2000)] to high frequencies. The correlated fluctuations of two probe spheresheld by a pair of optical tweezers within a viscoelastic medium are determinedusing optical interferometry. A theoretical model is developed to yield thefrequency-dependent one- and two-particle response functions from thecorrelated motion. We demonstrate the validity of this method by determiningthe one- and two-particle correlations in a semi-dilute solution of polystyrenein decalin. We find that the ratio of the one- and two-particle responsefunctions is anomalous which we interpret as evidence for a slip boundarycondition caused by depletion of polymer from the surface of the particle.
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