Researcher: Canbaz, Ferda
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Canbaz, Ferda
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Publication Metadata only 2.3-μm Tm3+: YLF laser passively Q-switched with a Cr2+: ZnSe saturable absorber(Optical Soc Amer, 2017) N/A; N/A; Canbaz, Ferda; Yorulmaz, İsmail; Sennaroğlu, Alphan; PhD Student; PhD Student; Faculty Member; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; 23851We report, what is to our knowledge, the first passively Q-switched operation of a 2.3-mu m Tm3+ : YLF laser by using a Cr2+ : ZnSe saturable absorber. In the experiments, a tunable Ti3+ : sapphire laser was used to end pump the Tm3+ : YLF gain medium inside an x cavity. A Cr2+ : ZnSe saturable absorber was also included in the cavity to initiate passive Q switching. At all pump power levels above lasing threshold, passively Q-switched operation of the Tm3+ : YLF laser could be obtained at 2309 nm with pulse durations and repetition frequencies in the ranges of 1.21.4 mu s and 0.3-2.1 kHz, respectively. Analysis of power dependent repetition rate data further gave an estimated value of 3.1% for the round-trip saturable loss of the Cr2+ : ZnSe saturable absorber.Publication Metadata only Kerr-lens mode-locked 2.3-mu m tm3+:ylf laser as a source of femtosecond pulses in the mid-infrared(Optical Soc Amer, 2017) N/A; N/A; Department of Physics; Canbaz, Ferda; Yorulmaz, İsmail; Sennaroğlu, Alphan; PhD Student; PhD Student; Faculty Member; Department of Physics; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; 23851We report what is to our knowledge a new source of femto-second pulses in the mid-infrared, based on a Kerr-lens mode-locked (KLM) Tm3+ : YLF laser at 2303 nm. An un-doped ZnSe substrate was included in the resonator to provide enhanced nonlinear phase modulation during KLM operation. The Tm3+ : YLF laser was end-pumped with a continuous-wave Ti3+ : sapphire laser at 780 nm. With 880 mW of pump power, we generated 514-fs pulses at a pulse repetition rate of 41.5 MHz with an average power of 14.4 mW. The spectral width (full width at half-maximum) was measured as 15.4 nm, giving a time-bandwidth product of 0.44. We foresee that the wide availability of this gain medium, as well as the straightforward pumping scheme near 800 nm, will make 2.3-mu m, mode-locked Tm3+ : YLF lasers versatile sources of ultrashort pulses in the mid-infrared. (C) 2017 Optical Society of AmericaPublication Metadata only Dual-wavelength temporal dynamics of a gain-switched 2-mu m Tm3+:Lu2O3 ceramic laser(IEEE-Inst Electrical Electronics Engineers Inc, 2018) N/A; N/A; Department of Physics; Toker, Işınsu Baylam; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; 23851We provide a detailed experimental investigation of the energy efficiency and rich temporal dynamics of a gain-switched 2-mu m Tm3+:Lu2O3 ceramic laser pumped near 800 nm. A tunable Ti3+:sapphire laser was used to determine the full excitation spectrum and the optimum pumping bands for the 1.5% Tm3+:Lu2O3 ceramic gain medium. These bands were centered at 774, 796, and 811 nm. The highest output pulse energy was obtained when the pump wavelength was set to 796 nm. In the experiments, a free-running x-cavity was used to investigate the energy efficiency of the Tm3+:Lu2O3 ceramic laser. Extracavity grating-dispersed output and prism-tuned resonator were used to further assess the role of cross-relaxation for the 1.5% Tm3+:Lu2O3 ceramic. Finally, we demonstrate that as the pump energy was increased, a transition occurred from-single-wavelength output (2068 nm) to dual-wavelength multipulse output (2068 and 1968 nm). We performed systematic temporal and spectral characterization measurements by using the free-running resonator, extracavity-grating-dispersed laser output, and prism-tuned resonator to investigate how the laser pulses at 1968 and 2068 nm evolved in time. A plane-wave rate equation model was further used to investigate the temporal dynamics of the Tm3+:Lu2O3 ceramic laser and provided predictions in qualitative agreement with experimental data.Publication Metadata only Gain-matched output couplers for efficient Kerr-lens mode-locking of low-cost and high-peak power Cr:LiSAF lasers(Institute of Electrical and Electronics Engineers (IEEE), 2015) Chen, Li-Jin; Sumpf, Bernd; Erbert, Goetz; Leitenstorfer, Alfred; Kaertner, Franz X.; Demirbas, Umit; Department of Physics; N/A; N/A; N/A; Sennaroğlu, Alphan; Beyatlı, Ersen; Canbaz, Ferda; Cihan, Can; Faculty Member; PhD Student; PhD Student; PhD Student; Department of Physics; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; 23851; N/A; N/A; N/AWe present a detailed investigation of Kerr-lens mode-locking in diode-pumped Cr:LiSAF lasers employing gain-matched output couplers (GMOCs). Single-mode diodes (660 nm, 130 mW) and tapered diodes (685 nm, 1 W) were investigated as diode pump sources. We have shown that, by reducing the gain-filtering effect, GMOC enhances the effective self-amplitude modulation depth and provides a significant improvement in both efficiency and robustness of KLM operation. From the single-mode diode pumped system, 13 fs pulses with an average power of 25 mW and a peak power 25 kW have been generated at an incident pump power of only 120 mW (21% optical-to-optical conversion efficiency). The tapered diode pumped Cr: LiSAF oscillator provided pulses as short as 14.5 fs with 106-mW average power and 60-kW peak power at an incident pump power of 940 mW (11% optical-to-optical conversion efficiency). A femtosecond tuning range extending from 807 to 919 nm was also realized with sub-50-fs long pulses. To our knowledge, demonstrated optical-to-optical conversion efficiencies, peak powers and fs tuning ranges are record results for Cr: LiSAF laser oscillators. The obtainable pulsewidth and fs tuning range are currently limited by the dispersion/reflectivity bandwidth of the available optics.Publication Metadata only Graphene mode-locked operation of Tm3+:YLiF4 and Tm3+:KY3F10 lasers near 2.3 µm(Optical Society of America (OSA), 2020) Tonelli, Mauro; Bae, Ji Eun; Rotermund, Fabian; Petrov, Valentin; N/A; N/A; Department of Physics; Canbaz, Ferda; Muti, Abdullah; Sennaroğlu, Alphan; PhD Student; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; 23851We report experimental demonstration of graphene modelocked operation of Tm3+:YLiF4 (YLF) and Tm3+:KY3F10 (KYF) lasers near 2.3 mu m. To scale up the intracavity pulse energy, the cavity was extended, and double-end pumping was employed with a continuous-wave, tunable Ti3+:sapphire laser delivering up to 1 W near 780 nm. The extended Tm3+: KYF laser cavity was purged with dry nitrogen to eliminate pulsing instabilities due to atmospheric absorption lines, but this was not needed in the case of the Tm3+:YLF laser. Once initiated by graphene, stable uninterrupted mode-locked operation could be maintained with both lasers. With the extended cavity Tm3+:YLF laser, 921 fs pulses were generated at a repetition rate of 17.2 MHz at 2304 nm. 739 fs pulses were obtained at the repetition rate of 54 MHz from the Tm3+:KYF laser at 2340 nm. The corresponding pulse energy and peak power were 2.4 nJ and 2.6 kW for the Tm3+:YLF laser, and 1.2 nJ and 1.6 kW for the Tm3+:KYF laser. We foresee that it should be possible to generate shorter pulses at higher pump levels. (C) 2020 Optical Society of AmericaPublication Metadata only Graphene mode-locked femtosecond Cr:LiSAF laser(Optical Society of America (OSA), 2015) Kakenov, N.; Kocabas, C.; Demirbas, U.; N/A; Department of Physics; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; N/A; 23851We report the first demonstration of femtosecond pulse generation from a Cr:LiSAF laser mode-locked with a monolayer graphene saturable absorber. Nearly transform-limited 72-fs pulses were generated at 850 nm with only two 135-mW pump diodes.Publication Metadata only Graphene mode-locked Cr:LiSAF laser at 850 nm(Optica Publishing Group, 2015) Kakenov, Nurbek; Kocabaş, Coşkun; Demirbaş, Ümit; N/A; Department of Physics; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; N/A; 23851We report, for the first time to our knowledge, a mode-locked femtosecond Cr:LiSAF laser initiated with a high-quality monolayer graphene saturable absorber (GSA), synthesized by chemical-vapor deposition. The tight-focusing resonator architecture made it possible to operate the Cr:LiSAF laser with only two 135 mW, 660 nm low-cost single-mode diode lasers. At a pump power of 270 mW, the laser produced nearly transform-limited 68 fs pulses with an average power of 11.5 mW at 850 nm. The repetition rate was around 132 MHz, corresponding to a pulse energy and peak power of 86 pJ and 1.26 kW, respectively. Once mode locking was initiated with the GSA, stable, uninterrupted femtosecond pulse generation could be sustained for hours. The saturation fluence and the modulation depth of the GSA were further determined to be 28 mu J/cm(2) and 0.62%, respectively. (C) 2015 Optical Society of AmericaPublication Metadata only Graphene mode-locked diode-pumped Cr: LiSAF laser at 857 nm(Optica Publishing Group (formerly OSA), 2014) Kakenov, N.; Kocabas, C.; Demirbas, U.; N/A; Department of Physics; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; N/A; 23851N/APublication Metadata only Sub-20 femtosecond pulse generation with a graphene mode-locked solid-state laser(Optica Publishing Group (formerly OSA), 2016) Kakenov, N.; Kocabas, C.; Demirbas, U.; N/A; Department of Physics; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; College of Sciences; N/A; 23851We generated 19-fs pulses with a low-threshold, diode-pumped graphene mode-locked Cr:LiSAF laser near 850 nm. To the best of our knowledge, these represent the shortest pulses generated to date with a graphene mode-locked laser.Publication Metadata only Gain-matched output couplers (GMOCs) for efficient and Robust Kerr-Lens mode-locking of Cr:LiSAF lasers(Institute of Electrical and Electronics Engineers (IEEE), 2014) Chen, Li-Jin; Sumpf, Bernd; Erbert, Goetz; Leitenstorfer, Alfred; Kaertner, Franz X.; Demirbaş, Ümit; N/A; N/A; N/A; Department of Physics; Cihan, Can; Beyatlı, Ersen; Canbaz, Ferda; Sennaroğlu, Alphan; PhD Student; PhD Student; PhD Student; Faculty Member; Department of Physics; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; 229317; N/A; 23851We report efficient and robust Kerr-lens mode-locking of single-mode and tapered diode-pumped Cr:LiSAF lasers by using gain-matched output couplers. Sub-15-fs pulses were generated with peak powers above 60-kW and optical-to-optical conversion efficiencies up to 21%.