000001609 001__ 1609
000001609 035__ $$a35084 
000001609 037__ $$aROMDOC-THESIS-2017-1090
000001609 041__ $$arum
000001609 100__ $$aŞandru, Alexandra
000001609 245__ $$aCercetări fundamentale şi aplicative în domeniul sistemelor optoelectronice bazate pe nanotehnologii 
000001609 260__ $$c2011-09-21
000001609 520__ $$aABSTRACT The PhD thesis entitled “Fundamental and applicative research in the field of optoelectronic systems based on nanotechnologies” includes a synthesis of the results the author has obtained based on her experience gathered as a PhD candidate within the doctoral programme POSDRU 5159, organized by the “Politehnica” University of Bucharest during November 2008- September 2011. The research topic elaborated during the doctoral stage encompassed a large range of theoretical and applicative studies in the field of modernizing optoelectronic systems based on nanotechnologies. The results obtained within the author’s doctoral research are both of theoretical and applicative nature. Theoretically, the author has defined three types of fractal structures with multiple applications in the field of designing artificial materials with a controlled internal structure capable of interacting with waves having frequencies of hundred of terahertz, as well as in the field of modernizing optoelectronic devices, especially those dealing with the spectral decomposition of light or aimed at improving the resolutions of images or modernizing the sensors intended for signalling the existence of distorted wavefronts. The research outcomes regarding these structures and their applicative potential have been published in the Journal of Modern Optics, DOI:10.1080/09500340. 2011.624646. Also from a theoretical point of view, the author has mathematically modeled the diffraction phenomena produced by the diffraction gratings that reproduce the configuration of the fractals defined in this thesis. The remarkable practical importance of the fractal structures introduced comprises in the fact that the circular shapes of their profiles allow the design of planar resonant configurations whose details can be realized at scales as small as 100 nm. For the actual implementation of resonators of this type the author has elaborated a software application needed in order to monitor the nanotechnologies used in the fabrication process. The operation scheme of this application has been filed at OSIM for patenting. The instruments of theoretical and practical nature referred to have proved their usefulness in designing new prototypes of metamaterials for frequencies close to the visible spectrum. These features have been verified within the author’s collaboration with the specialists from the Department of Photonics Engineering of the Technical University of Denmark. The results of the tests carried out in Denmark have been encouraging and they have later made the subject of two scientific communications presented within two international scientific events: “Prog. in Electromag. Res. Symp. (PIERS 2011), Suzhou, China, Sept.12-16, 2011” and “The Fifth Int. Cong. on Adv. Electromag. Mat. in Microwaves and Optics, Barcelona, Oct. 10 – 15, 2011”. Referring again to the applicative point of view, the fractal structures proposed by the author have proved their usefulness also for modernizing the presents sensors used to detect the distorted wavefronts. Although used in many and varied applications, the Shack-Hartmann sensors referred to, pose serious problems when it is expected that they deliver a real-time feedback. In this PhD thesis the author has designed three types of wavefront sensors, one for each fractal structure, capable of capturing the information from the environment, processing it and transmitting the appropriate answer in real-time, this aspect playing a great role in promoting adaptive optics system.
000001609 6531_ $$aNanotehnologie -- Teză de doctorat
000001609 6531_ $$aDispozitive optoelectronice -- Teză de doctorat
000001609 6531_ $$aFractali -- Teză de doctorat
000001609 6531_ $$aSenzori optici -- Teză de doctorat
000001609 6531_ $$aMetamateriale -- Teză de doctorat
000001609 8560_ $$ff_costache@library.pub.ro
000001609 8564_ $$uhttp://romdoc.upb.ro/record/1609/files/$$zAccess to Fulltext
000001609 980__ $$aTHESIS