Browsing by Subject "Reflection measurements"
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Item Open Access Absorption enhancement of molecules in the weak plasmon-exciton coupling regime(Optical Society of American (OSA), 2014) Balci, S.; Karademir, E.; Kocabas, C.; Aydınlı, AtillaWe report on the experimental and theoretical investigations of enhancing the optical absorption of organic molecules in the weak plasmon-exciton coupling regime. A metal-organic hybrid structure consisting of dye molecules embedded in the polymer matrix is placed in close vicinity to thin metal films. We have observed a transition from a weak coupling regime to a strong coupling one as the thickness of the metal layer increases. The results indicate that absorption of the self-assembled J-aggregate nanostructures can be increased in the weak plasmon-exciton coupling regime and strongly quenched in the strong coupling regime. A theoretical model based on the transfer-matrix method qualitatively confirms the experimental results obtained from polarization-dependent spectroscopic reflection measurements.Item Open Access All-chalcogenide glass omnidirectional photonic band gap variable infrared filters(AIP Publishing, 2009) Kondakci, H. E.; Yaman, M.; Koylu, O.; Dana, A.; Bayındır, MehmetWe report on the design, fabrication, and characterization of spatially variable infrared photonic band gap filter that consists of thermally evaporated, high refractive indexcontrast, amorphous chalcogenide glass multilayers. Due to graded thickness structure, the filter exhibits a position dependent stop band and a cavity mode ranging from 1.8 to 3.4 μm3.4 μmwavelengths. Reflection measurements on the variable filter agree well with theoretical calculations. These results pave the way to low-loss infrared mirrors, filters, spectral imaging, and miniaturized spectrometers at infrared region.Item Open Access Electrically controlled resistive switching assisted active ultra-broadband optical tunability in the infrared(IEEE, 2013) Battal, Enes; Özcan, Ayşe; Okyay, Ali KemalWe present an electrically tunable optical device with ultra-broadband tunability operating in 2-10 μm spectrum. We also, for the first time, optically observe resistive switching behavior in reflection measurements under electrical bias. © 2013 IEEE.Item Open Access Slowing surface plasmon polaritons on plasmonic coupled cavities by tuning grating grooves(American Institute of Physics, 2010-09) Balcı, Sinan; Kocabaş, Aşkın; Kocabaş, Coşkun; Aydınlı, AtillaWe investigate slow surface plasmon polaritons (SPPs) in plasmonic waveguiding bands formed by coupled plasmonic cavities on Moiŕ surfaces. We demonstrate controlling the group velocity and dispersion of the SPPs by varying the depth of the plasmonic Bragg grating groove. Changing the grating depth results in modification of coupling coefficients between the cavities and hence the SPPs group velocity is altered. Variation in the group velocity and dispersion of SPPs can be measured with polarization dependent spectroscopic reflection measurements. Dispersion of SPPs has been calculated by finite-difference time-domain method in agreement with the experimental data.Item Open Access Ultra hybrid plasmonics: Strong coupling of plexcitons with plasmon polaritons(OSA - The Optical Society, 2015) Balci, S.; Kocabas, C.We report a ternary-coupled plasmonic system consisting of excitons of J-aggregated dye, localized surface plasmon polaritons of Ag nanoparticles, and propagating surface plasmon polaritons of continuous Ag film. J-aggregate dyes are uniformly self-assembled on colloidally synthesized Ag nanoprisms forming plexcitonic nanoparticles, which are placed at a distance nanometers away from the Ag thin film. The reflection measurements, corroborated by theoretical predictions, reveal that the strong coupling of plasmon polaritons and plexcitons results in a newly formed plasmon-exciton-plasmon hybridized state that we call here, reportedly for the first time, a plexcimon state. The hybrid plasmonic system shows dispersion characteristics similar to a coupled resonator optical waveguide. The group velocity of the plexcimon state approaches zero at the band edges. The ultrahybrid plasmonic system presented here is promising for a variety of light-matter interaction studies, including polariton lasers, plasmonic devices, plasmonic waveguiding, and spectroscopy.