Browsing by Subject "Light reflection"
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Item Open Access Experimental investigation of layer-by-layer metallic photonic crystals(Institution of Electrical Engineers, 1998-12) Temelkuran, B.; Altug, H.; Özbay, EkmelThe authors have investigated the transmission properties and defect characteristics of layer-by-layer metallic photonic crystals. They have demonstrated experimentally that the metallicity gap of these crystals extends to an upper band-edge frequency, and no lower edge was detected down to 2 GHz. The defect structures built around these crystals exhibited high transmission peak amplitudes (100%) and high Q factors (2250). The crystals with low filling ratios (around 1-2%) were tested and were still found to possess metallic photonic crystal properties. These crystals exhibited high reflection rates within the metallicity gap and reasonable defect mode characteristics. A power enhancement factor of 190 was measured for the electromagnetic (EM) wave within planar cavity structures, by placing a monopole antenna inside the defect volume. These measurements show that detectors embedded inside a metallic photonic crystal can be used as frequency selective resonant cavity enhanced (RCE) detectors with increased sensitivity and efficiency when compared to conventional detectors.Item Open Access Fabry-Perot-type resonances in metallic photonic crystals(IEEE, 1998) Serpengüzel, Ali; Savran, KerimA metallic photonic crystals (MPC) with a face-centered cubic (FCC) Bravais lattice is investigated in the microwave regime. It was found that the transmission below and above the stop band is unity, which is quite remarkable since the metallic surface would have reflected 99.97% of the incident radiation in the given microwave frequency range. The effect of the incidence angle on the transmission of the MPC was also studied.Item Open Access Map building with multiple range measurements using morphological surface profile extraction(IEEE, Piscataway, NJ, United States, 1999) Barshan, B.; Başkent, D.A novel method is described for surface profile extraction based on morphological processing of multiple range sensor data. The approach taken is extremely flexible and robust, in addition to being simple and straightforward. It can deal with arbitrary numbers and configurations of range sensors as well as synthetic arrays. The method has the intrinsic ability to suppress spurious readings, crosstalk, and higher-order reflections, and process multiple reflections informatively. The essential idea of this work - the use of multiple range sensors combined with morphological processing - can be applied to different physical modalities of range sensing of vastly different scales and in many different areas. These may include radar, sonar, robotics, optical sensing and metrology, remote sensing, ocean surface exploration, geophysical exploration, and acoustic microscopy.Item Open Access Quarter wave Fresnel rhomb with colinear output beam(Optical Society of America Inc., Washington, DC, United States, 1999) Serpenguzel, A.A standard quarter wave (λ/4) Fresnel rhomb laterally displaces the output beam with respect to the input beam. This lateral displacement can cause problems when inserting the rhomb in an already aligned optical setup. This note describes the use of two λ/8 rhombs to construct a λ/4 rhomb. The output of the proposed rhomb is colinear with the input beam, and allows a much more flexible optical alignment.Item Open Access Reflection properties and defect formation in metallic photonic crystals(IEEE, 1998-05) Özbay, Ekmel; Temelkuran, Burak; Sigalas, M.; Tuttle, G.; Soukoulis, C. M.; Ho, K. M.The reflection properties of layer-by-layer metallic photonic crystals were investigated using metallic photonic crystals with simple-tetragonal (st) structure. The observed properties were used to predict defect formation in these crystals. The reflection and transmission amplitude characteristics were measured by a network analyzer and standard gain horn antennas. Transformation matrix method was employed for the theoretical simulations.