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Andreas Schmidt,
Simon Rivier,
Won Bae Cho,
Jong Hyuk Yim,
Sun Young Choi,
Soonil Lee,
Fabian Rotermund, Daniel Rytz,
Günter Steinmeyer,
Valentin Petrov,
Uwe Griebner
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ABSTRACT: Transmission- and reflection-type single-walled carbon nanotube saturable absorbers (SWCNT-SAs) were designed and fabricated for passive mode-locking of bulk lasers in the 1 microm spectral range. Mode-locked laser operation based on a diffusion-bonded Yb:KYW/KYW crystal was demonstrated, and pulses as short as 83 fs and 140 fs were achieved applying reflection-type and transmission-type SWCNT-SA, respectively. The nonlinear parameters of the absorbers were measured to be in close vicinity to those of a semiconductor saturable absorber mirror for the same wavelength range. Mode-locking performance with SWCNT-SAs and the SESAM was compared utilizing the same cavity, with the SESAM resulting in only slightly shorter pulses of 66 fs duration. The nearly identical performance indicates that well-optimized SWCNT-SAs can substitute SESAMs even in the 1 microm region.
Optics Express 10/2009; 17(22):20109-16. · 3.59 Impact Factor
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ABSTRACT: Single-pass pumping of a thin disk consisting of an only 50 microm thick epitaxial layer of 32 at.% Yb-doped KLu(WO(4))(2) grown on a 0.35 mm thick undoped KLu(WO(4))(2) substrate is demonstrated. The thin-disk laser delivered 9 W of continuous wave output power near 1030 nm with a slope efficiency of 77%.
Optics Letters 05/2008; 33(7):735-7. · 3.40 Impact Factor
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ABSTRACT: (K0.5Na0.5)NbO3 (KNN) is a potential lead-free replacement for Pb(Zr, Ti)O3 (PZT) piezoceramics, but its piezoelectric properties are inferior to those of PZT. By growing single crystals of KNN, it may be possible to improve the piezoelectric properties. Recently, single crystals of KNN were grown by the solid-state crystal growth (SSCG) method, but the crystals were very porous. In this paper, a method of growing dense single crystals by SSCG in a hot press will be described. (110)-oriented single seed crystals of KTaO3 were buried in KNN powder, with 0.5 mol% of K4CuNb8O23 added as a sintering aid. After consolidation by uniaxial and isostatic pressing, the tablets were hot pressed in a two-stage treatment. During hot pressing, dense single crystals of KNN grew using the KTaO3 seed crystal as a template. The effect of hot pressing on single crystal growth will be discussed.
Journal of the American Ceramic Society 03/2008; 91(5):1503 - 1507. · 2.27 Impact Factor
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ABSTRACT: Segmented growth of monoclinic Yb:KY(WO(4))(2) on KY(WO(4))2(2) substrates was successfully implemented and its excellent laser performance demonstrated. High slope efficiencies up to 80% and an output power of 375 mW were achieved under Ti:sapphire laser pumping in the continuous-wave regime. In the passively mode-locked regime, pulses as short as 99 fs with an average output power of 69 mW were obtained.
Optics Express 12/2007; 15(24):16279-84. · 3.59 Impact Factor
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ABSTRACT: Large thickness coupling factors k<sub>T</sub>≤0.7 are measured in both [001]<sub>C</sub> -oriented (45° cut in the orthorhombic ac plane), monodomain and [001]<sub>C</sub> -poled, domain-engineered single crystals of K Nb O <sub>3</sub> . k<sub>T</sub> is extremely stable over a large temperature range, remaining high (≥0.65) even upon heating and cooling through the orthorhombic-tetragonal phase transition. This is likely related to another finding that spontaneously high k<sub>T</sub> values (≤0.68) are observed in as-grown (unpoled), [001]<sub>C</sub> -cut, polydomain K Nb O <sub>3</sub> crystals. k<sub>T</sub> is also stable upon thinning to thicknesses below 60 μ m , as required for high-frequency applications. Finally, large k<sub>T</sub> values (≤0.7) are reported in [001]<sub>C</sub> -poled, polydomain, Li-doped ( K <sub>0.5</sub> Na <sub>0.5</sub>) Nb O <sub>3</sub> .
Applied Physics Letters 03/2007; · 3.84 Impact Factor
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ABSTRACT: Previous works on photorefractive self-organizing laser cavities were about lasers that oscillate, prior the self-organization process occurs, on a set of axial modes sharing the same transverse structure. In a well-designed broad-area laser diode extended cavity, we theoretically and experimentally demonstrate that the insertion of a photorefractive crystal can also affect the transverse modal structure to force the laser, initially oscillating on several transverse modes, to oscillate on a single transverse and axial mode. This spatial self-organization process leads to an enhancement of the single mode operating range of the laser.
Optics Express 05/2006; 14(7):2735-43. · 3.59 Impact Factor
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ABSTRACT: We report on the optical quality and laser performance of Czochralski-grown 2-at. %-doped Nd:YAG. Using a diode pumped laser in an end pumped configuration, we compare the laser performance of this material with the performance of 1-at. %-doped Nd:YAG and 0.7-at. %-doped Nd:YVO4 crystals. Experimental results show the superior performance of 2-at. % Nd:YAG over Nd:YVO4. With a pump power of 25.7 W, a maximum output power of 12.3 W with a slope efficiency of 57% and an optical-to-optical efficiency of 48% were achieved.
Applied Optics 08/2002; 41(21):4377-84. · 1.41 Impact Factor
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ABSTRACT: We demonstrate experimentally an optical parametric oscillator constructed in a waveguide induced by a photorefractive spatial soliton and show that the pumping threshold is reduced considerably.
Optics Letters 06/2002; 27(9):737-9. · 3.40 Impact Factor
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ABSTRACT: A photorefractive crystal inserted inside an extended cavity laser diode is an adaptive frequency filter. Without any other selective element, the mutual adaptation between the modes and the dynamic photorefractive hologram leads to a single-longitudinal-mode oscillation. We demonstrated this adaptive process with a 810-nm diffraction limited laser diode and a BaTiO3 photorefractive crystal. We analyzed the transient spectra from the initially multimode oscillation until the single-mode steady state.
Optics Communications.
