Ritchie, N.W.M.Story, J.G.Hulet, Randall G.2015-03-302015-03-301991Ritchie, N.W.M., Story, J.G. and Hulet, Randall G.. "Realization of a measurement of a ‘‘weak value’’." <i>Physical Review Letters,</i> 66, no. 9 (1991) American Physical Society: 1107-1110. http://dx.doi.org/10.1103/PhysRevLett.66.1107.https://hdl.handle.net/1911/79437We present the first realization of a measurement of a ‘‘weak value,’’ a concept recently introduced by Aharonov, Albert, and Vaidman (AAV). Our experiment uses a birefringent crystal to separate the two linear-polarization components of a laser beam by a distance small compared to the laser-beam waist. This ‘‘weak measurement’’ is followed by a strong measurement which translates the centroid of the beam by a distance far larger than the birefringence-induced separation. In addition, we present data corresponding to orthogonal initial and final states, for which the weak value is not defined. This interference effect may have application in the amplification and detection of weak effects.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1103/PhysRevLett.66.1107