Browsing by Subject "Optical multilayers"
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Item Open Access Filtering characteristics of hybrid integrated polymer and compound semiconductor waveguides(IEEE, 2002) Ozturk, C.; Huntington, A.; Aydınlı, Atilla; Byun, Y.T.; Dagli, N.This paper reports a study on a compact filter fabricated using hybrid integration of compound semiconductors and polymers. A GaAs epilayer is glued onto a polymer channel waveguide forming a highly asymmetrical directional coupler. This approach results in a narrow band filter due to very different dispersion characteristics of the compound semiconductor and the polymer materials. Furthermore, fiber coupling loss has been significantly reduced, since the input and output coupling is done through the polymer waveguide. Filtering characteristics can be engineered by changing the thickness and the length of the semiconductor epilayer. This can be done precisely using etch stop layers and noncritical lithography. The spectral response of such a filter can also be tuned electronically either using the electro-optic properties of the compound semiconductor or the thermo-optic properties of the polymer.Item Open Access Graphene-enabled optoelectronics on paper(American Chemical Society, 2016-06) Polat, E. O.; Uzlu, H. B.; Balci, O.; Kakenov, N.; Kovalska, E.; Kocabas, C.The realization of optoelectronic devices on paper has been an outstanding challenge due to the large surface roughness and incompatible nature of paper with optical materials. Here, we demonstrate a new class of optoelectronic devices on a piece of printing paper using graphene as an electrically reconfigurable optical medium. Our approach relies on electro-modulation of optical properties of multilayer graphene on paper via blocking the interband electronic transitions. The paper based devices yield high optical contrast in the visible spectrum with a fast response. Pattering graphene into multiple pixels, folding paper into three-dimensional shapes or printing colored ink on paper substrates enable us to demonstrate novel optoelectronic devices which cannot be realized with wafer-based techniques.Item Open Access Spectral scalability and optical spectra of fractal multilayer structures: FDTD analysis(Springer Verlag, 2017) Şimsek, Şevket; Palaz, Selami; Mamedov, Amirullah M.; Özbay, EkmelAn investigation of the optical properties and band structures for the conventional and Fibonacci photonic crystals (PCs) based on SrTiO3 and Sb2Te3 is made in the present research. Here, we use one-dimensional SrTiO3- and Sb2Te3-based layers. We have theoretically calculated the photonic band structure and transmission spectra of SrTiO3- and Sb2Te3-based PC superlattices. The position of minima in the transmission spectrum correlates with the gaps obtained in the calculation. The intensity of the transmission depths is more intense in the case of higher refractive index contrast between the layers. © 2016, Springer-Verlag Berlin Heidelberg.