Browsing by Author "Murthy, Y.L.N."

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Effect of polymer host on third order nonlinear optical properties of newly synthesized organic liquid crystal
(2007) Shettigar, S.; Umesh, G.; Poornesh, P.; Murthy, Y.L.N.
We report the investigation of third order optical nonlinearity of 2,4,6-tri-(p-hyptoyoxylphenyl) pyrilium tetraborate doped PMMA using nanosecond laser pulses at 532nm wavelength by employing Z-Scan technique. To see the effect of polymer host, the results have been compared with the pure dopant. The material shows a large negative nonlinearity with real and imaginary parts of X(3) are - 3.31�10-14esu and 0.73�10 -14esu respectively. Excited state absorption cross-section is found to be 3.41�10-48 cm4.s/photon in PMMA host. The magnitude of third order nonlinear parameters increases when the compound is doped into PMMA matrix because of change in the conformation of chain geometry as a result of charge transfer processes. The values are comparable with a best known nonlinear liquid crystal molecule namely, 4-cyano-4'-n-pentylbiphenyl in the nematic phase. Hence, these molecules can be suitably used as nonlinear optical materials in PMMA matrix for device applications. � 2007 IEEE.
Effect of polymer host on third order nonlinear optical properties of newly synthesized organic liquid crystal
(2007) Shettigar, S.; Umesh, G.; Poornesh, P.; Murthy, Y.L.N.
We report the investigation of third order optical nonlinearity of 2,4,6-tri-(p-hyptoyoxylphenyl) pyrilium tetraborate doped PMMA using nanosecond laser pulses at 532nm wavelength by employing Z-Scan technique. To see the effect of polymer host, the results have been compared with the pure dopant. The material shows a large negative nonlinearity with real and imaginary parts of X(3) are - 3.31Ã—10-14esu and 0.73Ã—10 -14esu respectively. Excited state absorption cross-section is found to be 3.41Ã—10-48 cm4.s/photon in PMMA host. The magnitude of third order nonlinear parameters increases when the compound is doped into PMMA matrix because of change in the conformation of chain geometry as a result of charge transfer processes. The values are comparable with a best known nonlinear liquid crystal molecule namely, 4-cyano-4'-n-pentylbiphenyl in the nematic phase. Hence, these molecules can be suitably used as nonlinear optical materials in PMMA matrix for device applications. Â© 2007 IEEE.
Synthesis, characterization and evaluation of the photophysical and nonlinear optical behaviour of novel 4-substituted arylidene-2-[5-(2,6- dichlorophenyl)-3-methyl-1,2-oxazol-4-yl]-1,3-oxazol-5-ones
(2013) Murthy, Y.L.N.; Kilaru, K.P.; Veeraiah, V.; Umesh, G.; Manjunatha, K.B.; Christopher, V.
Five new 4-substituted arylidene-2-[5-(2,6-dichlorophenyl)-3-methyl-1,2- oxazol-4-yl]-1,3-oxazol-5-ones have been designed and synthesized in order to study their third-order nonlinear optical properties. These novel compounds were characterized by advanced spectroscopic techniques (IR, 1H, 13C NMR, ESI-MS spectroscopy and elemental analyses). In addition, the evaluation of absorption and emission wavelengths of the new 5-oxazolone derivatives was carried out in seven different solvents of varying polarity, which showed intense absorption maxima at 350-480 nm and emission maxima at 390-535 nm respectively. The third-order nonlinear optical properties of the target molecules have been investigated in N,N-dimethylformamide using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The nonlinear refractive index, nonlinear absorption coefficient, magnitude of third-order susceptibility and molecular two photon absorption cross-sections have been determined. All of the compounds showed excellent optical limiting behaviour at 532 nm, with the best optical limiting behaviour observed with strong electron donor [dimethyl and N,N-diethyl amino] substituents. © 2013 Elsevier Ltd. All rights reserved.