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Enhanced optical transmission through metallic holes array: role of te polarization in spp excitation
, Article Plasmonics ; Volume 8, Issue 2 , June , 2013 , Pages 403-409 ; 15571955 (ISSN) ; Rashidian, B ; Sharif University of Technology
2013
Abstract
Optical transmission through double-layer metallic subwavelength holes array is studied under oblique incidence by split-field finite-difference time-domain method. Both TM and TE polarizations are investigated. It is proved that the transmission peaks can also be observed for TE polarization due to the excitation of surface plasmon polaritons (SPP) through diffraction orders. By changing the incident angle, these transmission peaks follow the SPP wavelength shift. The field profiles, even for the field components not present in the incident field, clearly show the SPP excitation. The mechanism of enhanced transmission will be fully discussed
The nonlinear diffusion bandwidth: A simple tool for optimizing dispersion maps
, Article Optical Transmission, Switching, and Subsystems IV, Gwangju, 5 September 2006 through 7 September 2006 ; Volume 6353 I , 2006 ; 0277786X (ISSN) ; 0819464481 (ISBN); 9780819464484 (ISBN) ; Fischer, J. K ; Louchet, H ; Jamshidi, K ; Petermann, K ; Sharif University of Technology
2006
Abstract
The concept of a nonlinear transfer function of a fibre-optic communication link is reviewed. Also an approximation of the nonlinear transfer function is introduced, which allows to define an equivalent single-span model of a dispersion-managed multi-span system. In this paper we will show its limits of validity and try to extent these limits by enhancing the theoretical model. In this respect we will discuss the impact of dispersion precompensation and show the influence of residual dispersion per span, number of spans and local dispersion on transmission systems with on-off keying and differential phase-shift keying modulation formats. This approach allows fast assessment of the...
Design of Plasmonic Systems for Nanobiophotonic Applications
, Ph.D. Dissertation Sharif University of Technology ; Rashidian, Bizhan (Supervisor) ; Vosoughi, Manouchehr (Supervisor) ; Shahrokhian, Saeed (Co-Advisor)
Abstract
In this thesis periodic plasmonic nanostructures are studied for detection of biological specious. The behavior of metal nanostructure arrays under normal incidence has been widely reported. However, simulation of periodic dispersive structures under oblique incidence requires newer formulations. Formulations, and algorithms based on modified split-field finite-difference time-domain (SF-FDTD) method are introduced, permitting analysis of metallic nanostructures arrays under oblique incidence. These novel algorithms are practically implemented on a parallel processing system based on graphics processing unit (GPU). Test and verification of these formulations are done by analyzing referenced...
Effect of graphene on the absorption and extraordinary transmission of light in 1-d metallic gratings
, Article IEEE Journal of Quantum Electronics ; Volume 53, Issue 3 , 2017 ; 00189197 (ISSN) ; Rahmani, B ; Khavasi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
Periodic metallic structures are known to support resonant extraordinary optical transmission (EOT). When covered with graphene, these structures can be employed to effectively manipulate the light. In this paper, we propose an analytical circuit model for graphene-covered 1-D metallic gratings. By using the circuit theory, we demonstrate that 1-D periodic array of cut-through slits, which are covered by a continuous graphene sheet, exhibits tunable EOT resonance for TM polarization whose amplitude, unlike its spectral position, can be dynamically tuned by varying the Fermi level of graphene. In this fashion, it is shown that placing a perfect reflector at the bottom of the graphene-covered...
Hierarchical on-chip routing of optical packets in large scale MPSoCs
, Article Proceedings of the 18th Euromicro Conference on Parallel, Distributed and Network-Based Processing, PDP 2010, 17 February 2010 through 19 February 2010, Pisa ; 2010 , Pages 515-524 ; 9780769539393 (ISBN) ; Hessabi, S ; Sharif University of Technology
2010
Abstract
In this paper, we extract analytical models for data transmission delay, power consumption, and energy dissipation of optical and traditional NoCs. Utilizing extracted models, we compare optical NoC with electrical one for varying values of link length and degree of multiplexing and calculate lower bound limit on the optical link length below which optical on-chip network loses its efficiency. Based on this constraint, we propose a novel hierarchical on-chip network architecture, named as H2NoC, which benefits from optical transmissions in large scale SoCs and overcomes the scalability problem resulted from lower bound limit on the optical link length. Performing a series of simulation-based...
Fast two-step microwave-activated synthesis of Mn doped ZnS nanocrystals: Comparison of the luminescence and doping process with thermochemical approach
, Article Journal of Luminescence ; Volume 131, Issue 4 , April , 2011 , Pages 721-726 ; 00222313 (ISSN) ; Hajisalem, G ; Taghavinia, N ; Houshiar, M ; Sharif University of Technology
2011
Abstract
In this work we report a fast two-step microwave activated synthesis of the ZnS:Mn nanocrystals. Zn(NO3)2 and Na2S 2O3 were used as the precursors and Mn(NO 3)2 was employed as the source of the impurity. The aqueous synthesis was based on the heat sensitivity of Na2S 2O3, which releases some S species on heating. Consequently, the reaction was well activated under microwave irradiation resulting in formation of ZnS:Mn nanocrystals. Thioglycerol (TG) was also used as the capping agent and the catalyst of the reaction. The synthesis process was done in two steps, i.e. 1 min irradiation without TG and then injection of TG and continuation of irradiation. ZnS:Mn nanocrystals were quickly formed...
Hierarchical opto-electrical on-chip network for future multiprocessor architectures
, Article Journal of Systems Architecture ; Volume 57, Issue 1 , 2011 , Pages 4-23 ; 13837621 (ISSN) ; Hessabi, S ; Sharif University of Technology
2011
Abstract
Importance of power dissipation in NoCs, along with power reduction capability of on-chip optical interconnects, offers optical network-on-chip as a new technology solution for on-chip interconnects. In this paper, we extract analytical models for data transmission delay, power consumption, and energy dissipation of optical and traditional NoCs. Utilizing extracted models, we compare optical NoC with electrical one and calculate lower bound limit on the optical link length below which optical on-chip network loses its efficiency. Based on this constraint, we propose a novel hierarchical on-chip network architecture, named as H2NoC, which benefits from optical transmissions in large scale...
CdO/PSi/Si photo detector
, Article International Journal of Nanotechnology ; Volume 6, Issue 10-11 , 2009 , Pages 997-1005 ; 14757435 (ISSN) ; Iraji zad, A ; Mahdavi, S. M ; Samadpoor, M ; Sharif University of Technology
2009
Abstract
In spite of various works which were carried out on CdO and porous Si (PSi) separately, the interesting properties of CdO/PSi/Si system are not known well. In this work, we study the photoconductivity of deposited CdO layer on PSi/Si system. PS and CdO layers were prepared by electrochemical anodisation of p-type crystalline silicon and pulsed laser deposition (PLD) of cadmium oxide target. Then samples were annealed in air at 500°C to increase their optical transmissions to a value as large as 90% for wavelengths above 700 nm. The XRD study reveals that the annealed films are polycrystalline with grain size of about 25 nm. SEM micrograph of the CdO/PSi/Si system indicates that CdO layer has...
Hydrothermal synthesis of ZnO nanorod arrays for photocatalytic inactivation of bacteria
, Article Journal of Physics D: Applied Physics ; Volume 42, Issue 22 , 2009 ; 00223727 (ISSN) ; Mehrabian, M ; Mirabbaszadeh, K ; Azimirad, R ; Sharif University of Technology
2009
Abstract
Arrays of ZnO nanorods were synthesized on ZnO seed layer/glass substrates by a hydrothermal method at a low temperature of 70 °C. The effect of pH > 7 of the hydrated zinc nitrate-NaOH precursor on the morphology and topography (e.g. size, surface area and roughness), the optical characteristics (e.g. optical transmission and band-gap energy), hydrophilicity and antibacterial activity of the grown ZnO nanostructure and nanorod coatings were investigated. For pH = 11.33 of the precursor (NaOH concentration of 0.10M), a fast growth of ZnO nanorods on the seed layer (length of ∼1 νm in 1.5 h) was observed. The fast growth of the ZnO nanorods resulted in a significant reduction in the optical...
Synthesis and electrochromic study of sol-gel cuprous oxide nanoparticles accumulated on silica thin film
, Article Thin Solid Films ; Volume 517, Issue 24 , 2009 , Pages 6700-6706 ; 00406090 (ISSN) ; Tohidi, H ; Moshfegh, A. R ; Sharif University of Technology
2009
Abstract
In this study, electrochromic properties of cuprous oxide nanoparticles, self-accumulated on the surface of a sol-gel silica thin film, have been investigated by using UV-visible spectrophotometry in a lithium-based electrolyte cell. The cuprous oxide nanoparticles showed a reversible electrochromic process with a thin film transmission reduction of about 50% in a narrow wavelength range of 400-500 nm, as compared to the bleached state of the film. Using optical transmission measurement, we have found that the band gap energy of the films reduced from 2.7 eV for Cu2O to 1.3 eV for CuO by increasing the annealing temperature from 220 to 300 °C in an N2 environment for 1 h. Study of the band...