Browsing by Author "Kiran, A.J."

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?(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.
Chalcones: Possible new materials for third-order nonlinear optics
(Nova Science Publishers, Inc., 2011) Kiran, A.J.; Chandrasekharan, K.; Kalluraya, B.; Shashikala, H.D.
'Search for potential materials' for third-order nonlinear optics has been of continuing interest in recent years. In this context, organic molecules are increasingly being recognized as the materials of the future because their molecular nature combined with the versatility of synthetic chemistry can be used to alter and optimize molecular structure to maximize third order nonlinear response. Chalcones have received considerable interest as materials for second-order nonlinear optical applications due to their ability to crystallize in noncentrosymmetric structure and their blue light transmittance. Being charge transfer compounds, chalcones can also possess large thirdorder nonlinearities due to their π-conjugated structure. In this article, we discuss the structure-nonlinear response relationship among a few chalcones and the possibility of using them for third-order applications. A meager or no work, to our knowledge, has been done so far on these molecules in this regard. Z-scan and degenerate four-wave mixing techniques were employed to investigate third-order optical nonlinearities of chalcone derivatives. Some of these molecules possess large χ (3) of magnitude as high as 10-12 esu and exhibit strong optical limiting properties. Possible mechanisms that are responsible for optical limiting property of these molecules have been discussed. . © 2011 by Nova Science Publishers, Inc. All rights reserved.
Nonlinear optical properties of p-(N,N-dimethylamino)dibenzylideneacetone doped polymer
(2008) Kiran, A.J.; Satheesh Rai, N.; Udayakumar, D.; Chandrasekharan, K.; Kalluraya, B.; Philip, R.; Shashikala, H.D.; Vasudeva Adhikari, A.V.
A bis-chalcone derivative, p-(N,N-dimethylamino) dibenzylideneacetone was synthesized. Its third-order nonlinear susceptibility was determined to be as high as 10-12 esu by employing single beam Z-scan and degenerate four wave mixing techniques using Nd:YAG 7 ns laser pulses at 532 nm. The compound was doped in to poly(methylmethacrylate) matrix and the third-order nonlinearity was investigated by using Z-scan technique. The nonlinear refractive index of the doped polymer is found to be negative, and its magnitude is of the order of 10-10 esu. The results show that the compound exhibits strong reverse saturable absorption and a good optical limiting property and hence may be used as a promising dopant material. The study on concentration dependence of nonlinear optical parameters has been presented. © 2007 Elsevier Ltd. All rights reserved.
Synthesis and nonlinear optical characterization of copolymers containing alternating 3,4-dialkoxythiophene and 1,3,4-oxadiazolydbenzene units
(2007) Udayakumar, D.; Kiran, A.J.; Vasudeva Adhikari, A.V.; Chandrasekharan, K.; Shashikala, H.D.
We report the synthesis and linear and third-order nonlinear optical (NLP) characterization of two novel copolymers containing alternating 3,4-dialkoxythiophene and 1,4-bis(1,3,4-oxadiazolyl)benzene units. The copolymers were synthesized with a precursor polyhydrazide route. Both copolymers exhibited fluorescence around 430 nm under the irradiation of UV light. The NLO measurements were made with the single-beam Z-scan technique with Nd:YAG nanosecond laser pulses at 532 nm. The nonlinear refractive index of the investigated copolymers was negative, and the magnitude was as high as 10 -10 esu. The samples exhibited strong reverse saturation absorption and very good optical limiting properties at the wavelength used. The concentration dependence of third-order NLO parameters was studied. ©2007 Wiley Periodicals, Inc.
The ultrafast nonlinear optical response and multi-photon absorption of a new metal complex in the near-infrared spectral range
(Institute of Physics Publishing, 2010) Kiran, A.J.; Lee, H.W.; Sampath Kumar, H.C.; Rudresha, B.J.; Badekai Ramachandra, B.; Yeom, D.-I.; Kim, K.; Rotermund, F.
A new coordination compound, chloro(1,10-phenanthroline-N, N ?)(triphenylphosphine)copper(I) dichloromethane, incorporated in poly(methyl methacrylate) exhibits superior nonlinear optical properties in the near-infrared spectral region. Its nonlinear response time and third-order nonlinear optical susceptibility at 800nm are ? 90fs and 1.8 × 10 -10esu, respectively. Considerable nonlinear absorption is observed with this sample, near 800 and 1250nm. The contribution of the excited states to the total nonlinear absorption process is discussed. The results reveal the potential of this newly designed compound for multi-photon absorption-based photonic applications. © 2010 IOP Publishing Ltd.
Ultrafast optical response of a new metal organic complex-polymer composite film
(2009) Kiran, A.J.; Lee, H.W.; Kumar, H.C.S.; Rudresha, B.J.; Bhat, B.R.; Yeom, D.-I.; Rotermund, F.
A new Cu-based metal organic complex incorporated into poly (methyl mathacrylate) film exhibits large and fast offresonant optical nonlinearity in the 800 to 1550 nm wavelength range. A large ?(3) value of 1.8�10-10 esu is estimated. � 2009 IEEE.
Ultrafast optical response of a new metal organic complex-polymer composite film
(2009) Kiran, A.J.; Lee, H.W.; Kumar, H.C.S.; Rudresha, B.J.; Badekai Ramachandra, B.R.; Yeom, D.-I.; Rotermund, F.
A new Cu-based metal organic complex incorporated into poly (methyl mathacrylate) film exhibits large and fast offresonant optical nonlinearity in the 800 to 1550 nm wavelength range. A large Î§(3) value of 1.8Ã—10-10 esu is estimated. Â© 2009 IEEE.
Z-scan and degenerate four wave mixing studies on newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units
(2006) Kiran, A.J.; Udayakumar, D.; Chandrasekharan, K.; Vasudeva Adhikari, A.V.; Shashikala, H.D.
The third-order nonlinear optical properties of newly synthesized copolymers containing alternating substituted thiophene and 1,3,4-oxadiazole units have been studied in DMF solution at 532 nm by using single beam Z-scan and degenerate four wave mixing techniques with nanosecond laser pulses. The variation of nonlinear response among the copolymers clearly indicates the dependence of ?(3) on donor and acceptor type of units present in the copolymers. The nonlinear refractive index, n2, of the investigated copolymers is found to be negative and the magnitude is as high as 10-10 esu. All samples exhibit strong reverse saturation absorption at the wavelength used and show good optical limiting of nanosecond pulses. The concentration dependence of n2 and the two-photon absorption coefficient (?) has been studied. © 2006 IOP Publishing Ltd.