Researcher:
Cihan, Can

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PhD Student

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Can

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Cihan

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Cihan, Can

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2014 - 20185

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Researcher Of Publications: search.filters.isAuthorOfPublication.f878c064-f673-4b00-a234-d77868d8523d

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    Sub-100-fs pulse generation from a Kerr-lens mode-locked Alexandrite laser
    (Optica Publishing Group (formerly OSA), 2018) Demirbaş Ümit; N/A; N/A; N/A; Department of Physics; Cihan, Can; Muti, Abdullah; Toker, Işınsu Baylam; Sennaroğlu, Alphan; PhD Student; 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; Graduate School of Sciences and Engineering; College of Sciences; N/A; N/A; N/A; 23851
    We report, to the best of our knowledge, the shortest pulses obtained from a Kerr-lens mode-locked multipass-cavity Alexandrite laser operating near 750 nm. The resonator produced 70-fs pulses with a time-bandwidth product of 0.331.
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    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/A
    We 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.
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    Graphene mode-locked femtosecond Alexandrite laser
    (2018) Kocabaş, Coşkun; N/A; N/A; Department of Physics; Cihan, Can; Demirbaş, Ümit; Sennaroğlu, Alphan; PhD.Student; Master 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; 20328; 23851
    We report for the first time, to the best of our knowledge, graphene mode-locked operation of a femtosecond Alexandrite laser at 750 nm. A multipass-cavity configuration was employed to scale the output energy and to eliminate spectral/Q-switching instabilities. By using a monolayer graphene saturable absorber, mode locking could be obtained. With 5W of pinup at 532 nm, nearly transform-limited, 65 fs pulses with a time-bandwidth product of 0.319 were generated. The mode-locked laser operated at a pulse repetition rate of 5.56 MHz and produced 8 mW output power, corresponding to a pulse energy and peak power of 1.4 nJ and 22 kW, respectively. These experiments further show that graphene can be used to initiate mode locking at wavelengths as low as 750 nm. (C) 2018 Optical Society of America
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    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; 23851
    We 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%.
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    70 femtosecond Kerr-lens mode-locked multipass-cavity Alexandrite laser
    (Optical Soc Amer, 2018) Demirbaş, Umit; N/A; N/A; N/A; Department of Physics; Department of Physics; Cihan, Can; Muti, Abdullah; Toker, Işınsu Baylam; Kocabaş, Aşkın; Sennaroğlu, Alphan; PhD Student; PhD Student; PhD Student; Faculty Member; 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; College of Sciences; N/A; N/A; N/A; 227753; 23851
    We report, to the best of our knowledge, the shortest femto-second pulses generated from a Kerr-lens mode-locked (KLM) Alexandrite laser operating near 750 nm. The Alexandrite gain medium was pumped with a continuous-wave (cw), 532 nm laser, and the performance of both the short and extended resonators was investigated. The use of an extended cavity eliminated the multi-wavelength spectral instabilities observed during the cw operation of the short cavity. Furthermore, since the repetition rate of the Alexandrite laser was reduced from 107 to 5.6 MHz, the resulting increase in the intracavity pulse energy provided enhanced Kerr nonlinearity and eliminated the Q-switching instabilities during mode- locked operation. The KLMMPC Alexandrite laser produced nearly transform-limited, 70 fs pulses at a pulse repetition rate of 5.6MHz with only 1 W of pump power. The time-bandwidth product was further measured to be 0.331. (C) 2018 Optical Society of America