Transient grating diffraction efficiency

Figure 2. Transient grating decays for 9,lO-bis(methylene)-anthracene labeled polyisoprene in dilute hexane solution. Tg and Tx are the diffraction efficiencies of the grating for the probe beam polarized parallel and perpendicular to the excitation beams (see Equations 1 and 2). The two curves are initially different because the excitation beams create an anisotropic orientational distribution of excited state transition dipoles. As backbone motions occur, the transition dipoles randomize and the two curves coalesce. Both curves eventually decay due to the excited state lifetime. The structure of the anthracene-labeled polyisoprene is also displayed, with the position of the transition dipole Indicated by a double arrow. (Reproduced from Ref. 7. Copyright 1986 American Chemical Society.)...

We investigated the effects of the various polarization of the writing beams on the grating formation. The diffraction efficiencies and surface modulations of the gratings recorded under different recording conditions are summarized in Table I. All the diffraction efficiency values in the table were measured at least one day after the gratings were recorded to ensure that there are no transient effects involved. The surface modulations of the gratings were studied by AFM. 

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