Showing papers by "Uwe Griebner published in 2010"
TL;DR: In this paper, single-walled carbon-nanotube absorbers are used for laser mode-locking and shown to exhibit low saturation fluence of <10 mu J cm(-2), low scattering losses, and an exceptionally rapid relaxation, with time constants reaching <100 fs.
Abstract: Single-walled carbon-nanotube absorbers are experimentally demonstrated for laser mode-locking. A saturable absorber device is used to mode-lock three different bulk solid-state lasers in a 500 nm-wide wavelength interval. The devices exhibit a low saturation fluence of <10 mu J cm(-2), low scattering losses, and an exceptionally rapid relaxation, with time constants reaching <100 fs. The latter two properties are explained by a decreased curling tendency and increased tube-to-tube interactions of the nanotubes, respectively. These properties are the result of an optimized manufacturing procedure in combination with the use of a starting material with a higher microscopic order. The decreased scattering enables universal use of these devices in bulk solid-state lasers, which tend to be highly sensitive against non-saturable device losses as caused by scattering. The favorable saturable absorption properties are experimentally verified by mode-locking the three lasers, which all exhibit near transform-limited performance with about 100 fs pulse duration. The complete and unconditional absence of Q-switching side bands verifies the small saturation fluence of these devices.
148 citations
TL;DR: The liquid core supercontinua show a higher degree of coherence, and the larger mode field area and the higher damage threshold of the water core enable significantly higher pulse energies of the white light pulses, ranging up to 0.39microJ.
Abstract: Supercontinuum generation in a water-filled photonic crystal fiber is reported. By only filling the central hollow core of this fiber with water, the fiber properties are changed such that the air cladding provides broadband guiding. Using a pump wavelength of 1200 nm and few-microjoule pump pulses, the generation of supercontinua with two-octave spectral coverage from 410 to 1640 nm is experimentally demonstrated. Numerical simulations confirm these results, revealing a transition from a soliton-induced mechanism to self-phase modulation dominated spectral broadening with increasing pump power. Compared to supercontinua generated in glass core photonic fibers, the liquid core supercontinua show a higher degree of coherence, and the larger mode field area and the higher damage threshold of the water core enable significantly higher pulse energies of the white light pulses, ranging up to 0.39microJ.
69 citations
TL;DR: The mode locking of the mixed sesquioxide single crystal Yb:LuScO(3) is demonstrated and this crystal is locally disordered and has the broadest emission spectrum of all sESquioxides known so far.
Abstract: The mode locking of the mixed sesquioxide single crystal Yb:LuScO(3) is demonstrated. This crystal is locally disordered and has the broadest emission spectrum of all sesquioxides known so far. Pulse durations as short as 111 and 74 fs were obtained using the semiconductor saturable absorber mirror and Kerr-lens mode locking, respectively. The latter regime was reached using a two-section distributed Bragg-reflector tapered diode laser as a pump source.
53 citations
TL;DR: Passive mode-locking using a SESAM is demonstrated for the Yb-doped cubic non-stoichiometric crystal CNGG which exhibits local disorder in this article.
39 citations
TL;DR: It is reported on mode locking of a bulk Cr:YAG laser by using a transmission-type single-walled carbon nanotube saturable absorber and stable and self-starting laser operation in the picosecond and femtosecond regimes is obtained.
Abstract: We report on mode locking of a bulk Cr:YAG laser by using a transmission-type single-walled carbon nanotube saturable absorber. Stable and self-starting laser operation in the picosecond and femtosecond regimes is obtained at wavelengths around 1.5μm. Tunable transform-limited sub-100fs pulses are generated at a repetition rate of 85MHz with an output power up to 110mW.
33 citations
TL;DR: A passively mode-locked femtosecond laser based on the self-frequency-doubling crystal Yb:Ca4YO(BO3)3, with shortest pulses obtained from an oscillator based on Yb3+-doped bulk material is demonstrated.
Abstract: We demonstrate a passively mode-locked femtosecond laser based on the self-frequency-doubling crystal Yb:Ca4YO(BO3)3. The oscillator is pumped by a novel two-section distributed Bragg-reflector tapered diode-laser. Pulses as short as 46 fs and 42 fs at 1050 nm are achieved for the E//Z polarization without and with external compression, respectively. These are, to the best of our knowledge, the shortest pulses obtained from an oscillator based on Yb3+-doped bulk material.
29 citations
TL;DR: Continuous wave (CW) room temperature laser operation of the monoclinic Ho(3+)-doped KLu(WO(4))(2) crystal is demonstrated using a diode-pumped Tm( 3+):KLu( WO( 4) crystal for in-band pumping.
Abstract: We demonstrate continuous wave (CW) room temperature laser operation of the monoclinic Ho3+-doped KLu(WO4)2 crystal using a diode-pumped Tm3+:KLu(WO4)2 laser for in-band pumping. The slope efficiency achieved amounts to ~55% with respect to the absorbed power and the maximum output power of 648 mW is generated at 2078 nm.
26 citations
TL;DR: In this article, the authors studied the performance of self-frequency doubling Yb:YAB and Yb-YCOB with a saturable absorber mirror at the fundamental wavelength with diode pumping.
Abstract: Passive mode locking of the self-frequency doubling Yb:YAB and Yb:YCOB crystals with a saturable absorber mirror is studied at the fundamental wavelength with diode pumping. All essential polarization orientations including the self-frequency doubling configuration are considered. For the first time sub-90 fs pulses at the fundamental are obtained with both materials and the improvement in terms of pulse length in comparison to previous work is about 2.3 times (Yb:YAB) and 2.8 times (Yb:YCOB). The Yb:YAB laser generates pulses as short as 87 fs at 1050 nm with a 0.4% output coupler. The shortest pulses (76 fs) are obtained with a Y-cut Yb:YCOB for E ∥ Z. With an output coupler of 0.4% the oscillation wavelength is 1056 nm. For E ∥ X the mode-locked Yb:YCOB laser operates on a different Stark transition (at longer wavelengths) than for E ∥ gg and E ∥ Z.
25 citations
TL;DR: In this article, the mode-locked operation of Nd:silicate glass with both single-walled carbon nanotubes (SWCNTs-SAM) and semiconductor saturable absorber mirrors (SESAMs) has been investigated.
Abstract: The mode-locked operation of Nd:silicate glass with both single-walled carbon nanotubes (SWCNTs-SAM) and semiconductor saturable absorber mirrors (SESAMs) has been investigated. SWCNT-SAM mode-locking has been optimized in Nd-doped bulk lasers for the first time, yielding 99-fs pulses at 1070 nm. For comparison, by using a SESAM instead of SWCNT-SAM, pulses as short as 87 fs and a tuning range of 30 nm were achieved. Related to the applied 200-mW single-mode laser diode as pump source the lasers were characterized by high efficiency and low threshold. The optimized low-power pump setup yielded a remarkable slope efficiency of 46.5% in the cw regime.
20 citations
TL;DR: A terahertz time-domain spectroscopy (THz-TDS) system using an optically pumped semiconductor disk laser and high-speed asynchronous optical sampling is reported in this paper.
Abstract: A terahertz time-domain spectroscopy (THz-TDS) system using an optically pumped semiconductor disk laser and high-speed asynchronous optical sampling is reported. The combination of these techniques holds considerable promise towards a compact and low-cost implementation of THz-TDS. The spectrometer offers a 333 ps time delay window scanned at 10 kHz and delivers more than 1.2 THz spectral coverage at a data acquisition time of one minute. As a proof-of-principle experiment, a 0.8 THz resonance of a frequency-selective surface structure was measured.
18 citations
TL;DR: In this article, a Nd:BaY2F8 (Nd: BaYF8) laser mode-locked using a single-walled carbon nanotube saturable absorber (SWCNT-SA) was demonstrated.
Abstract: Picosecond pulse generation near 1-μm wavelength has been achieved with a Nd:BaY2F8 (Nd:BaYF) laser mode-locked using a single-walled carbon nanotube saturable absorber (SWCNT-SA). The laser was operated at its main 1049-nm transition, generating 8.5-ps pulses with ≈70-mW output power for ≈570-mW absorbed pump power. This is the first demonstration of cw mode-locking in the picosecond regime with Nd-doped crystals and SWCNT-SAs. The requirements on the SWCNT-SA for successful mode-locking in relatively narrow-band neodymium lasers are reviewed and their implications are discussed.
31 Jan 2010
TL;DR: A passively Q-switched Tm:KLuW laser using Cr2+:ZnSe as saturable absorber delivered pulse energies as high as 16 µJ at a repetition rate of 6.5 kHz around 2 µm as mentioned in this paper.
Abstract: A passively Q-switched Tm:KLuW laser using Cr2+:ZnSe as saturable absorber delivered pulse energies as high as 16 µJ at a repetition rate of 6.5 kHz around 2 µm.
TL;DR: In this article, the authors achieved the shortest pulse duration for diode-pumped model-ocked Yb-doped monoclinic double tungstate oscillators with an average power of 22 mW.
Abstract: Pulses as short as 65 fs at an average power of 22 mW were achieved from a passively modelocked laser at 1039 nm based on a Yb-doped diffusion-bonded KY(WO 4 ) 2 crystal. To the authors' best knowledge, this is the shortest pulse duration for diode-pumped modelocked Yb-doped monoclinic double tungstate oscillators.
16 May 2010
TL;DR: In this paper, the authors observed the generation of supercontinua from a hollow core photonic crystal fiber filled with water, which spans the spectral range from 410 to 1650 nm and has a high energy of 0.4 µJ.
Abstract: We observe the generation of supercontinua from a hollow-core photonic crystal fiber filled with water. The observed supercontinuum spans the spectral range from 410 to 1650 nm and has a high energy of 0.4 µJ.
TL;DR: In this paper, the main results obtained in relation with crystalline layers obtained by Liquid Phase Epitaxial growth of lanthanide doped KLu(WO 4 ) 2 and Nb:RbTiOPO 4 were summarized in terms of their compositional homogeneity, structural stress in the layer/substrate interface and laser and waveguiding performances.
TL;DR: In this article, the authors demonstrate the first thin disk epitaxial Tm-laser based on the monoclinic KLu(WO4)2 with 15 at. % doping.
Abstract: We demonstrate the first thin disk epitaxial Tm-laser based on the monoclinic KLu(WO4)2 with 15 at. % doping. The
doped epitaxial layer serving as an active medium is only 80 μm thick. The large absorption enables efficient pumping
with only a single double pass of the pump radiation from the diode-laser. For output coupling between 0.4% and 2.8 %,
the slope efficiency in the continuous-wave regime is in the 7-11% range and the laser threshold is 1.5...2.5 W of
absorbed pump power. The laser emission spectra are centered at ~1850, 1915 and 1940 nm for output couples of 2.8%,
1.6% and 0.4% transmission, respectively. In all cases the emission spectra are "structured", consisting of a number
(typically 5...10) of narrow emission lines spread irregularly over 15...30 nm.
16 May 2010
TL;DR: Passive mode locking of the self-frequency doubling Yb∶Ca 4 YO(BO 3 ) 3 pumped by a two-section distributed Bragg-reflector tapered-diode-laser is demonstrated in this article.
Abstract: Passive mode locking of the self-frequency doubling Yb∶Ca 4 YO(BO 3 ) 3 pumped by a two-section distributed Bragg-reflector tapered-diode-laser is demonstrated. Pulses as short as 49 fs at 1050 nm are achieved for the E//Z polarization.
31 Jan 2010
TL;DR: Femtosecond mode-locking of Yb:KYW at 1.04 μm, Cr:forsterite at 1.,25 μm and a Cr:YAG at 1,50 μm using one and the same transmission-type single-walled carbon nanotube saturable absorber is demonstrated in this paper.
Abstract: Femtosecond mode-locking of Yb:KYW at 1.04 μm, Cr:forsterite at 1.25 μm and a Cr:YAG at 1.50 μm lasers using one and the same transmission-type single-walled carbon nanotube saturable absorber is demonstrated.
16 May 2010
TL;DR: Transmissive single-walled carbon nanotube saturable absorbers were used for passive mode-locking of a Cr:YAG laser, delivering tunable sub-100-fs pulses around 1.5 µm with output powers up to 110mW at 84.6 MHz as mentioned in this paper.
Abstract: Transmissive single-walled carbon nanotube saturable absorbers were used for passive mode-locking of a Cr:YAG laser, delivering tunable sub-100-fs pulses around 1.5 µm with output powers up to 110mW at 84.6 MHz.
16 May 2010
TL;DR: In this article, the authors combine high-speed asynchronous optical sampling with semiconductor disk femtosecond laser technology and realize a high-resolution THz time-domain spectrometer without mechanical delay.
Abstract: We combine high-speed asynchronous optical sampling with semiconductor disk femtosecond laser technology and realize a high-resolution THz time-domain spectrometer without mechanical delay. The system has great potential for size and cost reduction of existing systems.
16 May 2010
TL;DR: PPMgSLT was used for mode-locking of a diode-pumped Nd:GdVO 4 laser by intracavity SHG as discussed by the authors, achieving output powers of up to 4.7 W and pulse durations as short as 3.2 ps.
Abstract: PPMgSLT is used for mode-locking of a diode-pumped Nd:GdVO 4 laser by intracavity SHG. Stable and self-starting operation is observed achieving output powers of up to 4.7 W and pulse durations as short as 3.2 ps.
31 Jan 2010
TL;DR: In this paper, the authors achieved stable and self-starting mode-locking by cascaded second order nonlinearity using PPMgSLT nonlinear crystal in a Nd:GdVO4 laser, achieving average powers up to 5.1 W and pulse durations as short as 3.8 ps.
Abstract: Stable and self-starting mode-locking is achieved by cascaded second order nonlinearity using PPMgSLT nonlinear crystal in a Nd:GdVO4 laser, achieving average powers up to 5.1 W and pulse durations as short as 3.8 ps.
16 May 2010
TL;DR: In this paper, the first Ho:KLuW laser operating at room temperature was presented, resonantly pumped by a diode-pumped Tm:KLW laser and emitted at 2060 nm in E//N m polarization with a slope efficiency of 22%.
Abstract: We present the first cw Ho:KLuW laser operating at room temperature. It is resonantly pumped by a diode-pumped Tm:KLuW laser and emits at 2060 nm in E//N m polarization with a slope efficiency of 22%.
16 May 2010
TL;DR: In this article, a femtosecond mode-locking of three bulk lasers using one and the same saturable absorber was demonstrated in a >500 nm near-infrated band.
Abstract: Controlling bundling and curl of carbon nanotubes permits ultrafast optical switching, which was demonstrated in a >500 nm near-infrated band by femtosecond mode-locking of three bulk lasers using one and the same saturable absorber.