Browsing by Subject "Solid state lasers"
Now showing 1 - 17 of 17
- Results Per Page
- Sort Options
Item Open Access Ablation-cooled material removal at high speed with femtosecond pulse bursts(OSA, 2015) Kerse, Can; Kalaycıoğlu, Hamit; Elahi, Parviz; Akçaalan, Önder; Yavaş, S.; Aşık, M. D.; Kesim, Deniz Koray; Yavuz, Koray; Çetin, Barbaros; İlday, Fatih ÖmerWe report exploitation of ablation cooling, a concept well-known in rocket design, to remove materials, including metals, silicon, hard and soft tissue. Exciting possibilities include ablation using sub-microjoule pulses with efficiencies of 100-mJ pulses.Item Open Access Advances in femtosecond single-crystal sum-frequency generating optical parametric oscillators(IEEE, 1998) Köprülü, Kahraman G.; Kartaloğlu, Tolga; Dikmelik, Yamaç; Aytür, OrhanThe effect of compensating the group velocity mismatch between the orthogonal pump components on the conversion efficiency of the optical parametric oscillators (OPOs) was investigated. A femtosecond single-crystal sum-frequency generating optical parametric oscillators (OPO) based on a Ti:sapphire laser pumped KTiOPO4 crystal was used. presented. The crystal was phase matched for a specific signal wavelength corresponding to the operational wavelength of the laser. The crystal was also phase-matched for the sum-frequency generations (SFG) of the pump and the signal beams yielded a blue output beam. The conversion efficiency of the OPOs increased by compensating the group velocity mismatch.Item Open Access All-fiber, single-mode spectral beam combining of high power Tm-doped fiber lasers(OSA, 2015) Yılmaz, S.; Ottenhues, C.; Wysmolek, M.; Theeg, T.; Lamrini, S.; Scholle, K.; Fuhrberg, P.; Sayınç, H.; İlday, Fatih Ömer; Neumann, J.; Overmeyer, L.; Kracht, D.Signal beam combining of Tm-doped fiber lasers can increase the laser output power while simultaneously maintaining the single mode beam quality. We demonstrate an all-fiber integrated dual-wavelength Tm-doped fiber laser with an output power of 36 W by using the spectral beam combining method. The constituent lasers are operating at the wavelengths 1949 and 1996 nm and an in-house-made WDM is used for combination of these two different wavelengths. All-fiber truly single mode power combining is demonstrated for the first time in this wavelength region.Item Open Access Femtosecond pulse generation from an extended cavity Cr4+: Forsterite laser using graphene on YAG(Optical Society of America, 2013) Baylam I.; Ozharar, S.; Natali Cizmeciyan, M.; Balcı, Osman; Pince, Erçağ; Kocabaş, Coşkun; Sennaroglu, A.A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013.Item Open Access Focus issue introduction: Advanced Solid-State Lasers (ASSL) 2014(Optical Society of American (OSA), 2015) Schepler, K.L.; Jeong, Y.; Jiang, S.; Gallo, K.; Taira, T.; Omer Ilday F.The editors introduce the focus issue on "Advanced Solid-State Lasers (ASSL) 2014," which is based on the topics presented at a congress of the same name held in Shanghai, China, from October 27 to November 1, 2014. This Focus issue, jointly prepared by Optics Express and Optical Materials Express, includes 28 contributed papers (21 for Optics Express and 7 for Optical Materials Express) selected from the voluntary submissions by attendees who presented at the congress and have extended their work into complete research articles. We hope this focus issue offers a useful snapshot of the variety of topical discussions held at the congress and will contribute to the further expansion of the associated research areas. © 2015 OSA.Item Open Access Focus issue introduction: Advanced Solid-State Lasers (ASSL) 2015(OSA - The Optical Society, 2016) Gallo K.; Jeong Y.; Taira T.; Jiang S.; Ilday, F. O.The editors introduce the focus issue on "Advanced Solid-State Lasers (ASSL) 2015", which is based on the topics presented at a congress of the same name held in Berlin, Germany, from October 4 to October 9, 2015. This focus issue, jointly prepared by Optics Express and Optical Materials Express, includes 23 contributed papers (17 for Optics Express and 6 for Optical Materials Express) selected from the voluntary submissions from attendees who presented at the congress and have extended their work into complete research articles. We hope this focus issue offers a good snapshot of a variety of topical discussions held at the congress and will contribute to the further expansion of the associated research areas. © 2016 Optical Society of America.Item Open Access Generation of Sub-20-fs Pulses From a Graphene Mode-Locked Laser(OSA - The Optical Society, 2017) Canbaz, F.; Kakenov, N.; Kocabas, C.; Demirbas, U.; Sennaroglu, A.We demonstrate, what is to our knowledge, the shortest pulses directly generated to date from a solid-state laser, mode locked with a graphene saturable absorber (GSA). In the experiments, a low-threshold diode-pumped Cr3+:LiSAF laser was used near 850 nm. At a pump power of 275 mW provided by two pump diodes, the Cr3+:LiSAF laser produced nearly transform-limited, 19-fs pulses with an average output power of 8.5 mW. The repetition rate was around 107 MHz, corresponding to a pulse energy and peak power of 79 pJ and 4.2 kW, respectively. Once mode locking was initiated with the GSA, stable, uninterrupted femtosecond pulse generation could be obtained. In addition, the femtosecond output of the laser could be tuned from 836 nm to 897 nm with pulse durations in the range of 80-190 fs. We further performed detailed mode locking initiation tests across the full cavity stability range of the laser to verify that pulse generation was indeed started by the GSA and not by Kerr lens mode locking. � 2017 Optical Society of America.Item Open Access Graphene mode-locked femtosecond Cr: LiSAF laser(Optical Society of America (OSA), 2015) Canbaz F.; Kakenov, N.; Kocabas, C.; Demirbas, U.; Sennaroglu, A.We 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.Item Open Access Graphene supercapacitor as a voltage controlled saturable absorber for femtosecond pulse generation(OSA, 2014) Baylam, I.; Çizmeciyan, M. N.; Özharar, S.; Polat, Emre Ozan; Kocabaş, Coşkun; Sennaroğlu, A.For the first time to our knowledge, we employed a graphene supercapacitor as a voltage controlled saturable absorber at bias voltages of 0.5-1V to generate 84-fs pulses from a solid-state laser near 1255 nm.Item Open Access Graphene-gold supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation(OSA, 2015) Baylam, I.; Balcı, Osman; Kakenov, Nurbek; Kocabaş, Coşkun; Sennaroğlu, A.We report, for the first time to our knowledge, a voltage-controlled graphene-gold supercapacitor saturable absorber, as a modulator with adjustable insertion loss for low-gain mode-locked lasers. Nearly transform-limited, 80-fs pulses were generated near 1240 nm.Item Open Access High energy dissipative raman soliton laser through XPM stabilization(Optical Society of America (OSA), 2015-10) Ergeçen, E.; Tegin, Uğur; Elahi, Parviz; Şenel, Ç.; İlday, F. ÖmerDispersion, nonlinearity and gain determine the intracavity pulse behaviour. We show that pump depletion and XPM play a significant role in the stabilization of high energy dissipative Raman solitons. Using this theoretical knowledge, we predict and demonstrate 7-nJ femtosecond pulses at 1120 nm. © OSA 2015.Item Open Access High-speed transparent indium-tin-oxide based resonant cavity Schottky photodiode with Si/sub 3/N/sub 4//SiO/sub 2/ top Bragg mirror(IEEE, Piscataway, NJ, United States, 2000) Bıyıklı, Necmi; Kimukin, I.; Aytur, O.; Özbay, Ekmel; Gokkavas, M.; Unlu, S.Photodetectors demonstrating high bandwidth-efficiency (BWE) products are required for high-performance optical communication and measurement systems. For conventional photodiodes the BWE product is limited due to the bandwidth-efficiency trade-off. A resonant cavity enhanced (RCE) photodetection scheme offers the possibility to overcome this limitation. Very high BWE products are achieved using Schottky and p-i-n type RCE photodiodes, which could not be reached with conventional detector structures. Even better performances should be possible for RCE Schottky photodiodes if one can get rid of the optical losses and scattering caused by the Schottky metal, Au, which also serves as the top mirror of the resonant cavity. The transparent, low resistivity material indium-tin-oxide (ITO) is a potential alternative to thin semi-transparent Au as a Schottky-barrier contact material. We report our work on high-performance ITO-based RCE Schottky photodiodes.Item Open Access Influence of pump noise on mode-locked fiber oscillators(OSA, 2015) Teamir, Tesfay G.; Elahi, Parviz; Budunoğlu, İbrahim Levent; Gürel, Kutan; İlday, Fatih ÖmerPump modulation transfer function (MTF), and its dependence on pump power are investigated for all normal dispersion, dispersion managed and soliton-like mode-locked oscillator both in experiment and simulation. We find that cavity losses and pulse instabilities such as multiple pulsing influence noise transfer, strongly.Item Open Access Nonlinearity management of fiber oscillator with multiple gain segments(IEEE, 2015) Teamir, Tesfay G.; İlday, Fatih ÖmerOscillator with two gain segments is used to manage nonlinearity level and distribution. Results suggest that pulse evolution subject to an effective negative nonlinearity arising from complex interaction of gain filtering, dispersion, SFM and chirp.Item Open Access Phase-matched self-doubling optical parametric oscillator(Optical Society of America, 1997-03-01) Kartaloğlu, T.; Köprülü, K. G.; Aytür, O.We report a synchronously pumped intracavity frequency-doubled optical parametric oscillator that employs a single KTiOPO4 crystal for both parametric generation and frequency doubling. Both nonlinear processes are phase matched for the same direction of propagation in the crystal. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 745 nm, generates a green output beam at 540 nm with a 29% power conversion efficiency. Angle tuning in conjunction with pump wavelength tuning provides output tunability in the 530-585-nm range.Item Open Access Simultaneous phase matching of optical parametric oscillation and second-harmonic generation in aperiodically poled lithium niobate(Optical Society of American (OSA), 2003) Kartaloğlu, T.; Figen, Z. G.; Aytür, O.We report a simple ad hoc method for designing an aperiodic grating structure to quasi-phase match two arbitrary second-order nonlinear processes simultaneously within the same electric-field-poled crystal. This method also allows the relative strength of the two processes to be adjusted freely, thereby enabling maximization of the overall conversion efficiency. We also report an experiment that is based on an aperiodically poled lithium niobate crystal that was designed by use of our method. In this crystal, parametric oscillation and second-harmonic generation are simultaneously phase matched for upconversion of a femtosecond Ti:sapphire laser to 570 nm. This self-doubling optical parametric oscillator provides an experimental verification of our design method. © 2003 Optical Society of America.Item Open Access Single-crystal sum-frequency-generating optical parametric oscillator(Optical Society of America, 1999-09) Köprülü, K. G.; Kartaloğlu, T.; Dikmelik, Y.; Aytür, O.We report a synchronously pumped optical parametric oscillator that generates the sum frequency of the pump and the signal wavelengths. A single KTiOPO4 (KTP) crystal is used for both parametric generation and sum-frequency generation in which these two processes are simultaneously phase matched for the same direction of propagation. The parametric oscillator, pumped by a femtosecond Ti:sapphire laser at a wavelength of 827 nm, generates a blue output beam at 487 nm with 43% power-conversion efficiency. The polarization geometry of simultaneous phase matching requires rotation of the pump polarization before the cavity. Adjusting the group delay between the two orthogonally polarized pump components to compensate for the group-velocity mismatch in the KTP crystal increases the photon-conversion efficiency more than threefold. Angle tuning in conjunction with pump wavelength tuning provides output tunability in the 484–512-nm range. A plane-wave model that takes group-velocity mismatch into account is in good agreement with our experimental results.