Faculty Publications
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Item Third-order nonlinear optical properties and optical switching of palladium (I) complex(2011) Manjunatha, K.B.; Dileep, R.; Shelar, M.S.; Umesh, G.; Satyanarayan, M.N.; Badekai Ramachandra, B.R.We report the third-order nonlinear optical, optical power limiting and optical switching study of palladium-N-(2-pyridyl)-N′- (5-amino salicylidene) hydrazine triphenylphosphine, using Z-scan technique and pump-probe technique. The measured nonlinear refractive index is n 2=-6.022×10-9esu. The complex exhibits the reverse saturable absorption (RSA), the nonlinear absorption coefficient of β=10.748×10-9m/W. The good optical power limiting and optical switching behavior were observed in this complex. These suggest that this complex is a potential molecule for photonic applications. © 2011 American Institute of Physics.Item ?(3) measurements and optical limiting in dibenzylideneacetone and its derivatives(2006) Kiran, A.J.; Chandrasekharan, K.; Nooji, S.R.; Shashikala, H.D.; Umesh, G.; Kalluraya, B.We investigated the third order nonlinear optical properties of dibenzylidene acetone (1,5-diphenyl-1, 4-pentadeine-3-one) and its derivatives. The nonlinear measurements were performed by using single beam Z-scan technique with Q-switched Nd:YAG nanosecond laser pulses at 532 nm. Open aperture data for dibenzylidene and its derivatives demonstrate the presence of two-photon absorption at this wavelength. The dependence of ?(3) on donor/acceptor type substituents to the basic compound clearly shows the electronic origin of nonlinearity and hence demonstrates that the mechanism by which the third order nonlinear response enhanced is not by the thermal effects, but instead due to the strong nonlinear absorption and nonlinear refraction of the compounds. The derivatives of the basic compound show very good optical limiting behavior. © 2005 Elsevier B.V. All rights reserved.Item Nonlinear optical studies of 1-3-diaryl-propenones containing 4-methylthiophenyl moieties(2007) John Kiran, A.; Mithun, A.; Shivarama Holla, B.; Shashikala, H.D.; Umesh, G.; Chandrasekharan, K.The third-order nonlinear optical properties of chalcone derivatives have been studied using the single beam Z-scan technique. The dependence of ?(3) on different donor and acceptor type substituents demonstrates the electronic nonlinearity of compounds. The largest value of nonlinear refractive index, n2, measured for a high electron donor substituted molecule is -2.033 × 10-11 esu. These molecules exhibit a strong two-photon absorption and interesting optical limiting of nanosecond laser pulses at 532 nm. © 2006 Elsevier B.V. All rights reserved.Item Third-order nonlinear optical studies of newly synthesized polyoxadiazoles containing 3,4-dialkoxythiophenes(2006) Udayakumar, D.; John Kiran, A.; Vasudeva Adhikari, A.V.; Chandrasekharan, K.; Umesh, G.; Shashikala, H.D.The third-order nonlinear optical properties of newly synthesized soluble polyoxadiazoles containing 3,4-dialkoxythiophenes were investigated by using Z-scan and degenerate four-wave mixing (DFWM) techniques. The measurements were performed at 532 nm with 7 ns pulses from a Nd:YAG laser. We found a good agreement between the values of ?(3) determined from both the experiments. Z-scan results indicate a negative nonlinear refractive index, n2, whose magnitude is of the order of 10-10 esu for all the copolymers. The variation of nonlinear response among the copolymers clearly indicates the dependence of ?(3) on donor and acceptor type of units present in these copolymers. The copolymers exhibit strong reverse saturable absorption and good optical limiting properties at 532 nm. © 2006 Elsevier B.V. All rights reserved.Item Synthesis, characterization and studies on the nonlinear optical parameters of hydrazones(2010) Naseema, K.; Sujith, K.V.; Manjunatha, K.B.; Kalluraya, B.; Umesh, G.; Rao, V.Three hydrazones, 2-(4-methylphenoxy)-N?-[(1E)-(4-nitrophenyl)methylene]acetohydrazide (compound-1), 2-(4-methylphenoxy)-N?-[(1E)-(4-methylphenyl)methylene]acetohydrazide ((compound-2) and N?-{(1E)-[4-(dimethylamino)phenyl]methylene}-2-(4-ethylphenoxy) acetohydrazide(compound-3) were synthesized and their third order nonlinear optical properties were investigated using a single beam z-scan technique with nanosecond laser pulses at 532 nm. Open aperture data obtained from the three compounds indicates two photon absorption at this wavelength. The nonlinear refractive index n2, the nonlinear absorption coefficient ?, the magnitude of the effective third order susceptibility ?(3), the second order hyperpolarizability ?h and the coupling factor ? have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylidene acetone derivatives. Among the compounds studied, compounds-1 and 3 exhibited the better optical power limiting behaviour at 532 nm. Our studies suggest that compounds-1, 2 and 3 are potential candidates for optical device applications such as optical limiters and optical switches. © 2009 Elsevier Ltd. All rights reserved.Item Synthesis, characterization and studies on nonlinear optical parameters of 4-amino-5-(4-nitrophenyl)-1, 2, 4-triazole-3-thione(2010) Naseema, K.; Rao, V.; Manjunatha, K.B.; Umesh, G.; Sujith, K.V.; Kalluraya, B.In this paper, we report the synthesis, characterization and third order nonlinear optical properties of a new organic NLO material of 4-amino-5-(4-nitrophenyl)-1, 2, 4-triazole-3-thione (ANIT). The material was characterized by UV-vis and FTIR studies. The third order nonlinear optical properties have been investigated in dimethyl formamide (DMF) solution at 532 nm by using the Z-scan technique with pulses of nanoseconds duration. Open aperture data demonstrates the presence of two photon absorption at this wavelength. The nonlinear absorption coefficient ?, the nonlinear refractive index n2, the magnitude of effective third order susceptibility ?(3) and the second order hyperpolarizability ?h have been estimated as 2.99 cm/GW, -2. 53?×?10-11 esu, 2.72?×?10 -13esu and 0.281?×?10-31esu respectively. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The value of coupling factor have been estimated to be 0.17, indicating that the nonlinearity is electronic in origin. The compound exhibits good optical limiting at 532 nm with the limiting threshold of 80 ?J/pulse. The comparatively high value obtained indicates that this material may be used in optical device applications like optical limiters and optical switches. © 2010 Optical Society of India.Item ?(3) measurement and optical limiting studies of urea picrate(2011) Naseema, K.; Shyma, M.; Manjunatha, K.B.; Muralidharan, A.; Umesh, G.; Rao, V.The molecular charge complex urea picrate (UP) was synthesized and its third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. Open aperture data of the compound indicates two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient ?, magnitude of effective third order susceptibility ?(3), the second order hyperpolarizability ?h and the coupling factor ? have been estimated. The experimentally determined values of ?, n2, Re ?(3) and Im ?(3), ?h and ? of the compound UP are 2.146 cm/GW, -1.258×10-11 esu, -1.347×10-13 esu, 0.377×10-13 esu, 0.69×10-32 esu and 0.28, respectively. The compound exhibits good optical limiting at 532 nm with the limiting threshold of 80 ?J/pulse. Our studies suggest that compound UP is a potential candidate for optical device applications such as optical limiters. © 2011 Elsevier Ltd. All rights reserved.Item Third order optical nonlinearity and optical limiting studies of propane hydrazides(Elsevier B.V., 2012) Naseema, K.; Manjunatha, K.B.; Sujith, K.V.; Umesh, G.; Kalluraya, B.; Rao, V.Four hydrazones, 2-(4-isobutylphenyl)-N?-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N?-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)- N?-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N?-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient ?, magnitude of effective third order susceptibility ?(3), the second order hyperpolarizability ?h and the coupling factor ? have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of ?, n2, Re ?(3) and Im ?(3), ?h and ? of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches. © 2012 Elsevier B.V. All rights reserved.Item 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.Item Third order optical non-linearity of a novel chalcone derivative through Z scan technique(2013) Janardhana, K.; Ravindrachary, V.; Kumar, P.C.R.; Umesh, G.; Manjunatha, K.B.; Ismayil, N.A novel chalcone derivative 4-{ (1E,3Z)-3-(4-bromo phenyl]-3-[2-(2,4- dinitrophenyl) hydrazinylidene] prop-1-en-1-yl phenol [BPDP] has been synthesized and structurally characterized by NMR and FTIR studies. The third order non-linear optical properties of the BPDP have been studied using single beam Z scan technique with a nanosecond-pulsed Nd: YAG laser source at 532 nm. The coefficient of non linear refraction (y) of the compound is found to be negative as revealed by the signature of closed aperture data. The results obtained under open aperture configuration indicate that the material exhibits reverse saturation absorption. The magnitude of real part of third-order optical susceptibility 3)) and of molecular second order hyperpolarizability (Yh) are found to be -3.5x1w2U) m2W2 and -5.9x1W' m5W2, respectively. The thermo gravimetric analysis shows that the material possesses a very good thermal stability up to 203°C.