Conference Papers

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Author: search.filters.author.Manjunatha, K.B.Subject: search.filters.subject.Z-scan

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    Non linear optical properties of banana shaped liquid crystals
    (2011) Nagappa; Mahadeva, J.; Somashekar, R.; Yalemaggad, C.V.; Umesh, G.; Manjunatha, K.B.
    We report the nonlinear absorption and refraction of banana shaped liquid crystal, namely 1,3-phynelyne bis [N-(2-hydroxy-4-n-decyloxy-benzylidene)-4'- aminobenzoate] using Z-scan technique. The measurements were carried out using a Q-switched, frequency doubled Nd:YAG laser producing 7 nanosecond laser pulses at 532nm. The Z-scan result shows that the compound exhibits negative non-linearity. The nonlinear refractive index and nonlinear absorption coefficient of this compound were found to be -1.283 × 10-11 esu and 2.232cm/GW, respectively. The real and imaginary parts of the third-order nonlinear optical susceptibility were of the order of 10 -13 esu. The results suggest that these molecules are potential nonlinear optical materials for device applications. Copyright © Taylor & Francis Group, LLC.
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    Third order optical nonlinearity of a pyrazoline derivative
    (2011) Janardhana, K.; Ravindrachary, V.; Rajesh Kumar, P.C.R.; Yogisha; Poojary, B.; Manjunatha, K.B.; Ismayil, N.
    A new pyrazoline derivative 3-phenyl-5-(4-N,N-dimethylaminophenyl)-1H-2- pyrazoline (PDHP) was synthesized using standard method. The structure of the compound was established based on 1H NMR spectrum. The third-order optical nonlinear properties of PDHP compound were measured using nanosecond Z-scan method The measured nonlinear absorption coefficient β is 0.27×10-10m W-1. The magnitude of third order susceptibility is Reχ(3)==19.94×10-13 esu and Imχx (3)=5.85×10-13 esu. These experimental results reveal that the PDHP may be a good candidate for optical limiting applications due to its reverse saturated absorption phenomenon. © 2011 American Institute of Physics.
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    Nonlinear optical studies of a novel pyrazoline
    (2012) Janardhana, K.; Ravindrachary, V.; Rajesh Kumar, P.C.R.; Umesh, G.; Manjunatha, K.B.; Ismayil, N.
    A novel pyrazoline, 3-(phenyl)-5-(4-hydroxyphenyl)-1-(2, 4-dinitrophenyl)-2-pyrazoline (PHDP) was synthesized using standard method and its chemical structure was confirmed using FTIR studies. The linear and non linear optical properties of the compound were studied using UV-Vis and Z-scan techniques. UV-Vis spectrum shows that the compound is transparent in the visible region and absorption in the UV region. The z-scan study shows that the compound possesses third and higher order optical nonlinearity. The calculated optical absorption cross sections indicate that the operating nonlinear mechanism is reverse saturable absorption type. The real part of the third-order nonlinear optical susceptibility χ3 was estimated and the closed aperture data shows that PHDP possess negative nonlinearity. © 2012 American Institute of Physics.