http://hdl.handle.net/2289/148 Search the Channel search http://dspace.rri.res.in:8080/jspui/simple-search http://hdl.handle.net/2289/5335 Title: Synthesis, characterization, and nonlinear optical properties of donor-acceptor conjugated polymers and polymer/Ag nanocomposites<br/><br/>Authors: Murali, M. G; Dalimba, Udayakumar; Sridharan, Kishore<br/><br/>Abstract: Two new donor–acceptor (D–A) conjugated polymers P1 and P2 containing 3,4-didodecyloxythiophene and 1,3,4-oxadiazole units are synthesized via Wittig reaction methodology. Cyclic voltammetry studies reveal that the polymers are both p and n dopable, and possess low-lying LUMO energy levels (−3.34 eV for P1 and −3.46 eV for P2) and high-lying HOMO energy levels (−5.34 eV for P1 and −5.27 eV for P2). The optical band gap of the polymers is in the range of 2.25–2.29 eV, calculated from the onset absorption edge. The polymers emit orange to yellow light in the film state when irradiated with a UV light. The synthesized polymers are used to prepare polymer nanocomposites with different wt% of silver nanoparticles. The polymer nanocomposites are characterized by UV–Vis absorption spectroscopy, field emission scanning electron microscopy, and thermogravimetric analysis. Both polymers and polymer/Ag nanocomposites show good thermal stability with onset decomposition temperature around 300 °C under nitrogen atmosphere. The nonlinear optical properties of polymers and polymer/Ag nanocomposites are measured by Z-scan technique. Both polymers and polymer nanocomposites show a good optical limiting behavior. Nearly five times enhancement in the nonlinear optical properties is observed for polymer/Ag nanocomposites. The value of effective two-photon absorption coefficient (β) is in the order of 10−10–10−11 m/W. These results indicate that the synthesized polymers (P1 and P2) and their Ag nanocomposites are expected to be good candidates for application in photonic devices.<br/><br/>Description: Restricted Access. http://hdl.handle.net/2289/5282 Title: Nonlinear optical studies of lead lanthanum borate glass doped with Au nanoparticles<br/><br/>Authors: Rajaramakrishnaa, R; Karuthedathb, Safakath; Anavekar, R V; Jain, H<br/><br/>Abstract: Synthesis, characterization and optical nonlinearity of lead lanthanum borate glass embedded with gold nanoparticles have been investigated. DSC thermogram shows characteristics glass transition temperature at Tg = 775 K. Glasses doped with Au were subjected to heat treatment at 823 K with different annealing time and then, slowly cooled to room temperature show striking ruby color. SAED and TEM analyses have confirmed that f.c.c. Au nanoparticles of ~ 40 nm size are present in these glasses. An absorption peak centered on 563 nm has been observed in heat treated samples, which is attributed to surface plasmon resonance of gold nanoparticles. Nonlinear optical studies with open aperture Z-Scan technique show saturable absorption for heat treated samples at low intensity and reverse saturable absorption in samples without heat treatment at high intensity.<br/><br/>Description: Restricted Access. http://hdl.handle.net/2289/5280 Title: Aharon-Vaidman quantum game with a Young-type photonic qutrit<br/><br/>Authors: Kolenderski, Piotr; Sinha, Urbasi; Youning, Li; Zhao, Tong; Volpini, Mathew; Cabello, Adan; Laflamme, Raymond; Jennewein, Thomas<br/><br/>Abstract: The Aharon-Vaidman (AV) game exemplifies the advantage of using simple quantum systems to outperform classical strategies. We present an experimental test of this advantage by using a three-state quantum system (qutrit) encoded in a spatial mode of a single photon passing through three slits. The preparation of a particular state is controlled as the photon propagates through the slits by varying the number of open slits and their respective phases. The measurements are achieved by placing detectors in the specific positions in the near and far fields after the slits. This set of tools allowed us to perform tomographic reconstructions of generalized qutrit states, and to implement the quantum version of the AV game with compelling evidence of the quantum advantage.<br/><br/>Description: Open Access http://hdl.handle.net/2289/5278 Title: Synthesis and characterization of a new conjugated polymer bearing pyrazole and thiophene moieties as potent NLO material<br/><br/>Authors: Vishnumurthy, K.A.; Adhikari, A.V.; Sunitha, M.S.; Philip, Reji<br/><br/>Abstract: In this communication we describe the design and synthesis of a new conjugated polymer (P) carrying 3,4-dialkoxythiophene, 1,3,4 oxadiazole and pyrazole units, from its monomers through condensation polymerization method. The structure of newly synthesized polymer was established by FT-IR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. Further, its electrochemical, linear and nonlinear optical properties of the polymer have been investigated. The optical and electrochemical band gap was found to be 2.39 eV. Z-scan results reveal that the polymer exhibits strong optical limiting behavior due to effective three-photon absorption (3PA). The value of 3PA coefficient was found to be 1.1×10-20 m3/W2, which is comparable to that of good optical limiting materials. The fluorescence quantum yield of the polymer in solution was determined using quinine sulfate as standard and it was found to be 42%.<br/><br/>Description: Restricted Access.Proceedings of AIP Conference Proceedings Vol.1391 on optics: phenomena, materials, devices, and characterization: Optics 2011: International Conference on Light Solid State Physics, P-652