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Department: search.filters.department.Department of PhysicsSubject: search.filters.subject.Crystallography

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Now showing 1 - 4 of 4
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    PublicationOpen Access
    Metallodielectric photonic crystals resonators
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2003) Department of Physics; Serpengüzel, Ali; Faculty Member; Department of Physics; College of Sciences; 27855
    K-u band Fabry-Perot type resonances have been observed in the stop band of a metallodielectric photonic crystal by transmission measurements at microwave frequencies. The metallodielectric photonic crystal has a face centered cubic Bravais lattice structure with a lattice constant of 15 mm. Metallic spheres with 6.35 mm diameter are placed at the lattice sites. The metallodielectric photonic crystal displayed a directional bandgap with a lower band edge of 13.0 GHz, an upper band edge of 21.5 GHz, and a center frequency of 17.25 GHz, corresponding to a stop bandwidth center frequency ratio of 50%. The maximum rejection at the band center is 35 dB, corresponding to a 7 dB per unit cell rejection ratio. The Fabry-Perot type resonance in the k(u) band has a quality factor of 200, with a maximum transmission peak of -5 dB.
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    PublicationOpen Access
    Refractive index-enhanced vortex lattices
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2005) Oktel, Mehmet Özgür; Department of Physics; Müstecaplıoğlu, Özgür Esat; Faculty Member; Department of Physics; College of Sciences; 1674
    Light propagation through vortex matter in atomic Bose-Einstein condensates is examined. It is shown that vortex matter can be used as a photonic crystal by a refractive index enhancement scheme. Band structure of the vortex lattice is numerically calculated. Index enhanced vortex matter is shown to exhibit large refractive index contrast with the dilute thermal gas background in the vortex core. Depending on the depth of the index contrast full or directional photonic band gaps are found in the band structure. Experimental parameters required to generate band gaps in the visible region of the electromagnetic spectrum are calculated.
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    PublicationOpen Access
    Semiconductor and dielectric microspheres for optoelectronic applications
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2005) Department of Physics; Department of Electrical and Electronics Engineering; Serpengüzel, Ali; Yılmaz, Yiğit Ozan; Kurt, Adnan; Faculty Member; Master Student; Teaching Faculty; Department of Physics; Department of Electrical and Electronics Engineering; College of Sciences; 27855; N/A; 194455
    Microspheres possess high quality factor morphology-dependent resonances, i.e., whispering gallery modes. These resonances have narrow linewidths necessary for applications to compact optoelectronic devices for wavelength division multiplexing. The morphology dependent resonances have high quality factors of 104 and 105 with channel spacings of 0.14 nm in glass and 0.05 nm in silicon microspheres.
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    PublicationOpen Access
    Zero-phonon-line emission of single molecules for applications in quantum information processing
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2005) Ehrl, M; Brauchle, C; Zumbusch, A.; Hellerer, Th.; Department of Physics; Kiraz, Alper; Müstecaplıoğlu, Özgür Esat; Faculty Member; Faculty Member; Department of Physics; College of Sciences; 22542; 1674
    A single photon source which generates transform limited single photons is highly desirable for applications in quantum optics. Transform limited emission guarantees the indistinguishability of the emitted single photons. This, in turn brings groundbreaking applications in linear optics quantum information processing within an experimental reach. Recently, self-assembled InAs quantum dots and trapped atoms have successfully been demonstrated as such sources for highly indistinguishable single photons. Here, we demonstrate that nearly transform limited zero-phonon-line (ZPL) emission from single molecules can be obtained by using vibronic excitation. Furthermore we report the results of coincidence detection experiments at the output of a Michelson-type interferometer. These experiments reveal Hong-Ou-Mandel correlations as a proof of the indistinguishability of the single photons emitted consecutively from a single molecule. Therefore, single molecules constitute an attractive alternative to single InAs quantum dots and trapped atoms for applications in linear optics quantum information processing. Experiments were performed with a home-built confocal microscope keeping the sample in a superfluid liquid Helium bath at 1.4K. We investigated terrylenediimide (TDI) molecules highly diluted in hexadecane (Shpol'skii matrix). A continuous wave single mode dye laser was used for excitation of vibronic transitions of individual molecules. From the integral fluorescence, the ZPL of single molecules was selected with a spectrally narrow interference filter. The ZPL emission was then sent to a scanning Fabry-Perot interferometer for linewidth measurements or a Michelson-type interferometer for coincidence detection.