• P S Narayanan

      Articles written in Journal of Chemical Sciences

    • Recent trends in the study of switching processes in ferroelectrics

      R Ravi P S Narayanan

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      Several ferroelectrics and materials showing ferroelectric-like switching behaviour have been widely investigated and both an exponential or power law ofts onE have been reported. However, the mechanism of polarization reversal and domain dynamics show a complexity that makes it difficult to generalize and draw a common rule for all types of ferroelectrics. Radiation damage, internal biasing fields and defects alter the switching characteristics and in this review including some of the work of the authors onTGS, sodium nitriteDSP etc, the present trends in the study of switching and the electroluminescence during switching have been discussed.

    • Raman induced phase conjugation spectroscopy

      B Raghavendra Prasad R Krishna Mohan C K Subramanian P S Narayanan

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      Raman induced phase conjugation (RIPC) spectroscopy is a relatively new coherent Raman spectroscopic (CRS) technique using optical phase conjugation (OPC), with which complete Raman spectra of transparent media can be obtained. It is a non-degenerate four-wave mixing technique in which two pulsed laser beams at Ω1 and Ω1 ± Δ where A corresponds to a vibrational frequency of a nonlinear medium mix with a third laser beam at Ω1 to generate a fourth beam Ω1± Δ, which is nearly phase conjugate to one of the beams at Ω1. With this technique one can measure the ratio of the resonant and nonresonant components of the third-order nonlinear susceptibilities of the nonlinear media. We have used this technique to get Raman spectra of well-known organic solvents like benzene etc., using pulsed Nd: YAG -dye laser systems. We have also studied the effect of delaying one of the interacting beams with respect to the others and the phase conjugate property of RIPC signals.

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