Researcher:
Dündar, Mehmet Ali

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Master Student

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Mehmet Ali

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Dündar

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Dündar, Mehmet Ali

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2007 - 20087

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Researcher Of Publications: search.filters.isAuthorOfPublication.650de3ff-5093-44df-8f1b-98745137d3c4

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    Raman lasing near 630 nm from stationary glycerol-water microdroplets on a superhydrophobic surface
    (Optical Soc Amer, 2007) Department of Physics; Department of Physics; N/A; Department of Physics; Department of Chemistry; Sennaroğlu, Alphan; Kiraz, Alper; Dündar, Mehmet Ali; Kurt, Adnan; Demirel, Adem Levent; Faculty Member; Faculty Member; Master Student; Teaching Faculty; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; College of Sciences; College of Sciences; 23851; 22542; N/A; 194455; 6568
    We demonstrate, for the first time to our knowledge, Raman lasing from stationary microdroplets on a superhydrophobic surface. In the experiments, glycerol-water microdroplets with radii in the 11-15 mu m range were pumped at 532 nm with a pulsed, frequency-doubled Nd:YAG laser. Two distinct operation regimes of the microdroplets were observed: cavity-enhanced Raman scattering and Raman lasing. In the latter case, the Raman lasing signal was higher than the background by more than 30 dB. Investigation of the Raman spectra of various glycerol-water mixtures indicates that lasing occurs within the glycerol Raman band. Raman lasing was not sustained; rather, oscillation would occur in temporally separated bursts. Increasing the rate of convective cooling by nitrogen purging improved the lasing performance and reduced the average interburst separation from 2.3 to 0.4 s.
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    Volume stabilization of single, dye-doped water microdroplets with femtoliter resolution
    (Optical Soc Amer, 2007) N/A; Department of Physics; Department of Physics; N/A; Department of Chemistry; Kiraz, Alper; Kurt, Adnan; Dündar, Mehmet Ali; Demirel, Adem Levent; Faculty Member; Teaching Faculty; Master Student; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; College of Sciences; 22542; 194455; N/A; 6568
    A self-control mechanism that stabilizes the size of Rhodamine B-doped water microdroplets standing on a superhydrophobic surface is demonstrated. The mechanism relies on I the interplay between the condensation rate that was kept constant and the evaporation rate induced by laser excitation, which critically depends on the size of the microdroplets. The radii of individual water microdroplets (>5 mu m) stayed within a few nano-meters during long time periods (up to 455 s). By blocking the laser excitation for 500 ms, the stable volume of individual microdroplets was shown to change stepwise.
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    Single water microdroplets resting on a superhydrophobic surface: largely tunable optical microcavities
    (IEEE, 2007) N/A; Department of Physics; Department of Physics; N/A; Department of Chemistry; Kiraz, Alper; Kurt, Adnan; Dündar, Mehmet Ali; Demirel, Adem Levent; Faculty Member; Teaching Faculty; Master Student; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; College of Sciences; 22542; 194455; N/A; 6568
    More than 9 nm tunability of the whispering gallery modes of water microdroplets resting on a superhydrophobic surface is demonstrated. Tunability was achieved by introducing evaporation or condensation in microdroplets in a mini humidity chamber.
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    Raman lasing in glycerol water microdroplets on a superhydrophobic surface
    (Optical Society of America, 2008) Department of Physics; Department of Physics; Department of Physics; Department of Chemistry; N/A; Sennaroğlu, Alphan; Kurt, Adnan; Kiraz, Alper; Demirel, Adem Levent; Dündar, Mehmet Ali; Faculty Member; Teaching Faculty; Faculty Member; Faculty Member; Master Student; Department of Physics; Department of Chemistry; College of Sciences; College of Sciences; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; 23851; 194455; 22542; 6568; N/A
    We report on the first observation of Raman lasing near 630 nm from 532-nm-pumped, glycerol-water microdroplets on a superhydrophobic surface. Results of cavity-enhanced Raman scattering and Raman lasing experiments are described.
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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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    PublicationOpen Access
    Erratum: Simple largely tunable optical microcavity
    (American Institute of Physics (AIP) Publishing, 2007) Department of Physics; Department of Chemistry; Kiraz, Alper; Kurt, Adnan; Dündar, Mehmet Ali; Demirel, Adem Levent; Faculty Member; Teaching Faculty; Faculty Member; Department of Physics; Department of Chemistry; College of Sciences; 22542; 194455; N/A; 6568
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    PublicationOpen Access
    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.