Researcher:
Doğanay, Sultan

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Undergraduate Student

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Sultan

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Doğanay

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Doğanay, Sultan

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2007 - 20085

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Researcher Of Publications: search.filters.isAuthorOfPublication.d177e051-6c7e-4c7f-afdb-fe2ead77445a

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Now showing 1 - 5 of 5
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    Haptic guidance for improved task performance in steering microparticles with optical tweezers
    (Optical Soc Amer, 2007) Department of Mechanical Engineering; Department of Physics; N/A; N/A; Department of Physics; Başdoğan, Çağatay; Kiraz, Alper; Büküşoğlu, İbrahim; Varol, Aydın; Doğanay, Sultan; Faculty Member; Faculty Member; Master Student; Master Student; Undergraduate Student; Department of Mechanical Engineering; Department of Physics; College of Engineering; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; 125489; 22542; N/A; N/A; N/A
    We report the manipulation of 4-5 mu m diameter polymer microspheres floating in water using optical tweezers (OT) and a haptic device (i.e. force-reflecting robotic arm). Trapped microspheres are steered using the end-effector of a haptic device that is virtually coupled to an XYZ piezo-scanner controlling the movements of the fluid bed. To help with the manipulations, we first calculate a collision-free path for the particle and then display artificial guidance forces to the user through the haptic device to keep him/her on this path during steering. Experiments conducted with 8 subjects show almost two-fold improvements in the average path error and average speed under the guidance of haptic feedback. (c) 2007 Optical Society of America.
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    Enhanced energy transfer in single glycerol/water microdroplets standing on a superhydrophobic surface
    (Elsevier Science Bv, 2007) N/A; Department of Physics; Department of Physics; Department of Physics; Department of Chemistry; Kiraz, Alper; Doğanay, Sultan; Kurt, Adnan; Demirel, Adem Levent; Faculty Member; Undergraduate Student; Teaching Faculty; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; College of Sciences; College of Sciences; 22542; N/A; 194455; 6568
    We demonstrate resonant enhancement of energy transfer from donor to acceptor molecules in single glycerol/water microdroplets standing on a superhydrophobic surface. At donor emission wavelengths resonant with a whispering gallery mode, we recorded energy transfer rates up to 10 times higher than the non-radiative (Fbrster) energy transfer rate, by using the gradual acceptor photobleaching technique. Optical images taken with donor and acceptor emission filters revealed the radiative (long-range) nature of the energy transfer mediated by the whispering gallery modes.
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    Enhanced radiative energy transfer in single glycerol/water microdroplets on a superhydrophobic surface
    (IEEE, 2008) N/A; Department of Physics; Department of Physics; Department of Physics; Department of Chemistry; Kiraz, Alper; Doğanay, Sultan; Kurt, Adnan; Demirel, Adem Levent; Faculty Member; Undergraduate Student; Teaching Faculty; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; College of Sciences; College of Sciences; 22542; N/A; 194455; 6568
    Up to 10 times enhancement in the energy transfer rate from donor to acceptor molecules is demonstrated at wavelengths resonant with a whispering gallery mode of a glycerol/water microdroplet standing on a superhydrophobic surface.
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    Laser emission from single, dye-doped microdroplets situated on a superhydrophobic surface
    (IEEE, 2007) Department of Physics; Department of Physics; Department of Physics; Department of Chemistry; N/A; Department of Physics; Department of Molecular Biology and Genetics; Sennaroğlu, Alphan; Kurt, Adnan; Kiraz, Alper; Demirel, Adem Levent; Dündar, Mehmet Ali; Kalaycıoğlu, Hamit; Doğanay, Sultan; Faculty Member; Teaching Faculty; Faculty Member; Faculty Member; Master Student; PhD Student; Undergraduated Student; Department of Chemistry; Department of Physics; Department of Molecular Biology and Genetics; College of Sciences; College of Sciences; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; 23851; 194455; 22542; 6568; N/A; N/A; N/A
    Optical microcavities are attractive in developing ultralow threshold lasers which hold a great promise for applications in optical communications systems and fundamental studies in cavity quantum electrodynamics. Up to date laser emission has been observed from various different optical microcavities: Microdisks, microspheres, micropillars, photonic crystal defect microcavities, and microdroplets flying in air. Here we report the observation of laser emission from single, stationary, dye-doped microdroplets situated on a superhydrophobic surface. In contrast to the previous demonstrations on microdroplets flying in air, the technique we use allows for the analysis of laser emission from a particular microdroplet over prolonged periods.
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    Single glycerol/water microdroplets standing on a superhydrophobic surface: optical microcavities promising original applications
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2007) Department of Physics; Department of Chemistry; Kiraz, Alper; Dündar, Mehmet Ali; Demirel, Adem Levent; Doğanay, Sultan; Kurt, Adnan; Sennaroğlu, Alphan; Yüce, Mehdi Yavuz; Faculty Member; Faculty Member; Undergraduate Student; Teaching Faculty; Faculty Member; Department of Physics; Department of Chemistry; Graduate School of Sciences and Engineering; College of Sciences; 22542; N/A; 6568; N/A; 194455; 23851; N/A
    Glycerol/water microdroplets take almost spherical shapes when standing on a superhydrophobic surface. Hence they are suitable to function as optical microcavities. Using Rhodamine B doped water microdroplets, large spectral tunability of the whispering gallery modes (WGMs) (>5 nm) was observed. Tunability was achieved by evaporation/condensation in a current controlled mini humidity chamber. Experiments revealed a mechanism stabilizing the volume of these microdroplets with femtoliter resolution. The mechanism relied on the interplay between the condensation rate that was kept constant and the size dependent laser induced heating. The radii of individual water microdroplets (>5 mu m) stayed within a few nanometers during long time periods (several minutes). By blocking the laser excitation for 500 msec, the stable volume of individual microdroplets were changed stepwise. Laser emission was also observed from Rhodamine B doped glycerol/water microdroplets using a pulsed, frequency-doubled Nd:YAG laser (lambda=532 nm) as the excitation source. The observed largely tunable WGMs and laser emission can pave way for novel applications in optical communication systems. Besides due to the sensitivity of the WGMs to the size and shape of the microdroplets, the results can find applications in characterizing superhydrophobic surfaces and investigating liquid-solid surfaces.