Researcher:
Görgülü, Adil Tolga

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Master Student

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Adil Tolga

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Görgülü

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Görgülü, Adil Tolga

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2011 - 20185

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    Spectroscopic characterization of Tm3+:TeO2-K2O-Nb2O5 glasses for 2- μm lasing applications
    (Elsevier Science Bv, 2012) Kurt, Adnan; Speghini, Adolfo; Bettinelli, Marco; Department of Physics; Department of Physics; Department of Physics; Görgülü, Adil Tolga; Çankaya, Hüseyin; Sennaroğlu, Alphan; Master Student; Researcher; Faculty Member; Department of Physics; College of Sciences; College of Sciences; College of Sciences; N/A; N/A; 23851
    We have performed detailed experiments to investigate the spectroscopic properties of a new type of tellurite based host doped with thulium: Tm2O3:(0.70)TeO2-(0.15)K2O-(0.15)Nb2O5 having Tm2O3 concentrations of 0.125, 0.25, 0.5, and 1.0 mol%. By performing a Judd-Ofelt analysis of the absorption bands, we obtained average radiative lifetimes of 2.57 +/- 0.20 and 0.35 +/- 0.01 ms for the H-3(4) and F-3(4) levels, respectively. Furthermore, we also observed that an increase in the Tm2O3 concentration from 0.125 to 1.0 mol% results in a decrease of the measured fluorescence lifetime from 814 to 439 mu s and from 258 to 47 mu s for the H-3(4) and F-3(4) levels, respectively, due to efficient non-radiative decay. The highest quantum efficiency of 32% was obtained for the sample doped with 0.125 mol% Tm2O3 for the H-3(4) level. Results show that cross relaxation becomes important as the ion concentration is increased, leading to the quenching of the 1460-nm band and enhancement of the 1860-nm emission. The highest emission cross section of 6.85 x 10(-21) Cm-2 measured for the 1860-nm band reveals the potential of this host for the development of 2-mu m lasers in bulk glass as well as fiber media. (C) 2011 Published by Elsevier B.V.
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    Spectroscopic investigation of TM3+: TEO2-K2O-NB2O5 glasses at different doping levels for 2 μm laser applications
    (Optical Society of America, 2011) Bettinelli, Marco; Speghini, Adolfo; Department of Physics; Department of Physics; N/A; N/A; Sennaroğlu, Alphan; Kurt, Adnan; Çankaya, Hüseyin; Görgülü, Adil Tolga; Faculty Member; Teaching Faculty; Researcher; Master Student; Department of Physics; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; 23851; 194455; N/A; N/A
    We have performed detailed experiments to investigate the spectroscopic properties of a new type of tellurite based host doped with thulium: Tm2O3:(0.70)TeO2–(0.15)K2O–(0.15)Nb2O5 having Tm2O3 concentrations of 0.125, 0.25, 0.5, and 1.0 mol%. By performing a Judd–Ofelt analysis of the absorption bands, we obtained average radiative lifetimes of 2.57±0.20 and 0.35±0.01 ms for the 3H4 and 3F4 levels, respectively. Furthermore, we also observed that an increase in the Tm2O3 concentration from 0.125 to 1.0 mol% results in a decrease of the measured fluorescence lifetime from 814 to 439 μs and from 258 to 47 μs for the 3H4 and 3F4 levels, respectively, due to efficient non-radiative decay. The highest quantum efficiency of 32% was obtained for the sample doped with 0.125 mol% Tm2O3 for the 3H4 level. Results show that cross relaxation becomes important as the ion concentration is increased, leading to the quenching of the 1460-nm band and enhancement of the 1860-nm emission. The highest emission cross section of 6.85×10−21 cm2 measured for the 1860-nm band reveals the potential of this host for the development of 2-μm lasers in bulk glass as well as fiber media.
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    Injection-seeded, narrow-line gain-switched Cr: ZnSe laser
    (Association for the Advancement of Artificial Intelligence, 2012) Department of Physics; Department of Physics; N/A; N/A; N/A; N/A; Sennaroğlu, Alphan; Kurt, Adnan; Çankaya, Hüseyin; Çizmeciyan, Melisa Natali; Beyatlı, Ersen; Görgülü, Adil Tolga; Faculty Member; Teaching Faculty; Researcher; PhD Student; PhD Student; Master Student; Department of Physics; College of Sciences; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; 23851; 194455; N/A; N/A; 229317; N/A
    Injection seeding with a continuous-wave Cr:ZnSe seed laser reduced the output spectral width of a second gain-switched Cr:ZnSe laser from 125 nm to 0.65 nm and enabled its tuning from 2255 nm to 2455 nm.
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    PublicationOpen Access
    Comparative spectroscopic investigation of Tm3+: tellurite glasses for 2-mu m lasing applications
    (Multidisciplinary Digital Publishing Institute (MDPI), 2018) Kurt, Adnan; Speghini, Adolfo; Bettinelli, Marco; Department of Electrical and Electronics Engineering; Department of Physics; Çankaya, Hüseyin; Görgülü, Adil Tolga; Sennaroğlu, Alphan; Researcher; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Department of Physics; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); College of Engineering; College of Sciences; N/A; N/A; 23851
    We performed a comparative spectroscopic analysis on three novel Tm3+: tellurite-based glasses with the following compositions Tm2O3: TeO2-ZnO (TeZnTm), Tm2O3: TeO2-Nb2O5 (TeNbTm), and Tm3+: TeO2-K2O-Nb2O5 (TeNbKTm), primarily for 2-mu m laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm3+ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd-Ofelt analysis, we determined the average radiative lifetimes of the H-3(4) level to be 2.55 +/- 0.07 ms, 2.76 +/- 0.03 ms and 2.57 +/- 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm2O3 concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm2O3 concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the H-3(4) level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm2O3 ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 +/- 0.34 x 10(-21) cm(2), revealing the potential of thulium-doped tellurite gain media for 2-mu m laser applications in bulk and fiber configurations.
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    PublicationOpen Access
    Injection-seeded, gain-switched tunable Cr:ZnSe laser
    (Optical Society of America (OSA), 2012) Kurt, Adnan; N/A; Department of Electrical and Electronics Engineering; Department of Physics; Çankaya, Hüseyin; Çizmeciyan, Melisa Natali; Beyatlı, Ersen; Görgülü, Adil Tolga; Sennaroğlu, Alphan; Researcher; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; N/A; 23851
    We report a narrow-linewidth, tunable, gain-switched Cr:ZnSe laser operating between 2255 and 2455 nm. The spectral width of the laser was reduced from 125 nm to 0.3 nm by using injection seeding. Seeding was achieved with a second tunable CW Cr:ZnSe laser. The output wavelength was varied by tuning the wavelength of the seed laser. The seeded oscillator produced as high as 157 mu J pulses with 598 mu J incident pump pulse energy at a repetition rate of 1 kHz. The slope efficiency was determined to be 26%.