Researcher:
Beyatlı, Ersen

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PhD Student

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Ersen

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Beyatlı

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Beyatlı, Ersen

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2012 - 201512

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Researcher Of Publications: search.filters.isAuthorOfPublication.50be575c-9e22-4784-b48e-f8d22d96fabf

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Now showing 1 - 10 of 12
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    Efficient and low-threshold alexandrite lasers pumped by high-brightness diodes
    (Optical Society of America (OSA), 2013) Baali, Ilyes; Kurt, Adnan; Sumpf, Bernd; Erbert, Götz; Leitenstorfer, Alfred; Demirbas, Umit; N/A; N/A; Department of Physics; Beyatlı, Ersen; Yorulmaz, İsmail; 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; 229317; N/A; 23851
    We present low-cost and highly efficient continuous-wave Alexandrite lasers pumped by recently developed high-brightness diodes. A 19-mW lasing threshold, 38% slope efficiency, 200 mW output power, and a broad tuning range (724-816 nm) were realized.
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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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    Efficient and low-threshold Alexandrite laser pumped by a single-mode diode
    (Optica Publishing Group, 2014) Kurt, Adnan; Demirbaş, Ümit; Yorulmaz, İsmail; Beyatlı, Ersen; Sennaroğlu, Alphan; PhD Student; PhD Student; Faculty Member; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; School of Medicine; N/A; 229317; 205925
    We report a low-threshold and efficient Alexandrite laser that is pumped by only one state-of-the-art single-spatial-mode diode. The pump diode provided 170 mW of output power at 635 nm. In continuous wave (cw) laser experiments, we demonstrated lasing thresholds as low as 13 mW, slope efficiencies as high as 36%, output powers up to 48 mW, and a tuning range extending from 736 nm to 823 nm. Laser slope efficiency, laser output power, fluorescence lifetime, and emission intensity were further shown to decrease monotonically with increasing temperature. Pure cw operation could be obtained under most circumstances. However, selfQ- switching (SQS) was also observed in slightly misaligned laser cavities. During SQS, stable pulses with pulsewidths in the 5-15 mu s range and pulse repetition rates in the 10-35 kHz range have been obtained. We believe that this compact and efficient Alexandrite laser system may be an attractive source for several applications.
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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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    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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    Low-cost low-threshold diode end-pumped Tm:YAG laser at 2.016 um
    (Springer, 2012) Kurt, Adnan; N/A; N/A; Department of Physics; Beyatlı, Ersen; Naghizadeh, Solmaz; 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; 229317; N/A; 23851
    We report a low-threshold continuous-wave Tm:YAG laser that can be excited near 785 nm with low-cost, single-mode AlGaAs laser diodes. Low-threshold operation was achieved using a tightly focused, astigmatically compensated x-cavity containing a 2-mm-thick Tm:YAG crystal with 5 % Tm3+ concentration. Two linearly polarized single-mode diodes operating at 785.8 nm were polarization coupled to end pump the resonator. With a 6 % output coupler, as high as 32 mW of output power could be obtained at 2016 nm with 184 mW of incident pump power. The output could be further tuned in the 1935-2035 nm range. Slope efficiency measurements indicated that cross-relaxation was very effective at this doping level. With a 2 % output coupler, lasing could be obtained with as low as 32.3 mW of pump power. In the limit of vanishing output coupling, the incident threshold pump power could be reduced to as low as 25 mW. To our knowledge, this is among the lowest lasing thresholds reported to date for continuous-wave, room-temperature thulium lasers.
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    Efficient and Robust Kerr-Lens mode-locking of Cr: LiSAF lasers using gain-matched output couplers
    (Optical Society of America (OSA), 2013) Chen, Li-Jin; Kärtner, Franz X.; Demirbas, Umit; N/A; N/A; Department of Physics; Canbaz, Ferda; Beyatlı, Ersen; 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; 229317; 23851
    We have demonstrated robust and efficient Kerr-lens mode-locked operation of a lowcost, diode-pumped Cr:LiSAF laser using a gain-matched output coupler. Sub-30-fs pulses with 80-pJ pulse energy have been demonstrated with 80 mW of pump power.
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    Highly efficient and robust operation of Kerr-lens mode-locked Cr:LiSAFlasers using gain-matched output couplers
    (Optical Society of America (OSA), 2014) Chen, Li-Jin; Kaertner, Franz X.; Demirbas, Umit; N/A; N/A; Department of Physics; Canbaz, Ferda; Beyatlı, Ersen; 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; 229317; 23851
    We present efficient and robust Kerr-lens mode locking (KLM) of a diode-pumped Cr:LiSAF laser using a gain-matched output coupler (GMOC). An inexpensive, battery-powered 660 nm single-spatial-mode diode was used as the pump source. GMOC enhances the effective self-amplitude modulation depth by reducing the gain-filtering effect in broadband KLM operation to provide significant improvement in efficiency and robustness. Pulsing can be initiated without careful cavity alignment and is sustained for hours. 13 fs pulses with an average power of 25 mW have been generated using only 120 mW of pump power. The corresponding pulse energy and peak power is 200 pJ and 15 kW for the 126 MHz repetition rate cavity. Optical-to-optical conversion efficiency of the system is 21%, which represents an order of magnitude improvement in reported efficiencies for such diode-pumped ultrashort-pulse KLM Cr: LiSAF lasers. The obtainable pulse width is currently limited by the dispersion bandwidth of the available optics and can be potentially reduced to below 7 fs. (C) 2014 Optical Society of America
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    Tapered diode-pumped continuous-wave alexandrite laser
    (Optical Society of America (OSA), 2013) Baali, Ilyes; Sumpf, Bernd; Erbert, Goetz; Leitenstorfer, Alfred; Demirbaş, Ümit; Department of Electrical and Electronics Engineering; Beyatlı, Ersen; Sennaroğlu, Alphan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Sciences; N/A; 23851
    We describe a low-cost and efficient alexandrite (Cr:BeAl2O4) laser that is pumped by a high-brightness tapered diode laser (TDL). The tapered diode (TD) provides up to 1.1 W of output power and its wavelength can be finetuned to either 680.4 nm (R1 line) or 678.5 nm (R2 line) for efficient in-line pumping. Continuous-wave (cw) output powers of 200 mW, slope efficiencies as high as 38%, and a cw tuning range extending from 724 to 816 nm have been achieved. To the best of our knowledge, the cw power levels and slope efficiencies are the highest demonstrated so far from such a minimal complexity and low-cost system based on the alexandrite gain medium. Consequently, TDs operating in the red spectral region have the potential to become the standard pump sources for cw alexandrite lasers in the near future.
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    PublicationOpen Access
    Self-Q-Switched Cr:LiCAF laser near 800 nm
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2013) Department of Physics; Beyatlı, Ersen; Sennaroğlu, Alphan; Demirbaş, Ümit; PhD Student; Faculty Member; Master Student; Department of Physics; College of Sciences; N/A; 23851; N/A
    Self-Q-switching (SQS) of lasers enable the generation of Q-switched pulses from simple laser cavities without using any additional saturable absorbers or active modulators. Earlier studies have reported SQS in ruby, Nd:YAG, and Cr:LiSAF lasers. However, these systems were mostly flashlamp pumped and required cooling of the crystal and/or misalignment of the laser cavity for the observation of SQS. In this presentation, for the first time to our knowledge, we report SQS operation of a Cr:LiCAF laser. SQS was achieved in an astigmatically compensated x-cavity containing only a Cr:LiCAF crystal that was end-pumped with a 130-mW continuous-wave (cw) diode at 660 nm. During regular cw operation, the laser produced a diffraction-limited beam with 50 mW of output power and had a spectral width of 0.5 nm near 795 nm. SQS operation of the Cr:LiCAF laser could be initiated by fine adjustment of the separation between the curved mirrors of the cavity and was observed at several mirror separations within the stability range of the resonator. During SQS operation, the laser generated pulses with about 5 microsecond duration in the 780-800 nm wavelength range, at repetition rates between 10 and 30 kHz. SQS operation was further accompanied with a decrease in the output power to the 30-45 mW range. In this regime, the output beam became multimode and spectral broadening up to 12.5 nm (FWHM) was observed.