Efficient Yb^3+:CaGdAlO_4 bulk and femtosecond-laser-written waveguide lasers

Hasse, Kore; Calmano, Thomas; Deppe, Bastian; Liebald, Christoph; Kränkel, Christian

doi:10.1364/ol.40.003552

Cited by 30 publications

(21 citation statements)

References 20 publications

(20 reference statements)

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“…Even shorter pulses should be supported by using gain materials with broader emission bandwidth. Particularly promising is Yb:CALGO [27], which exhibits a significantly broader spectral gain bandwidth than Yb:YAG allowing the amplification of the full VECSEL seed spectrum. Finally, an even more compact system could be realized with a mode-locked integrated external-cavity surface emitting laser (MIXSEL) [30] as seed source, which integrates the semiconductor saturable absorber and the gain chip.…”

Section: Resultsmentioning

confidence: 99%

“…To improve the confinement of the laser mode the translation is superimposed with a sine oscillation with an amplitude of 3.5 µm and an oscillation frequency of 70 Hz. In contrast to previous waveguides fabricated in Hamburg [16,24,27] a pinhole with 600 µm diameter was inserted in the beam path of the fs-laser to improve its beam quality by mode cleaning. Due to the large distance between the pinhole and the aspheric focusing lens (f = 3.1 mm, NA = 0.68) employed for the laser inscription, only the 0th order of the resulting diffraction pattern is transmitted through the aperture of this lens.…”

Section: Yb:yag Waveguide Amplifiermentioning

confidence: 99%

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High-power amplification of a femtosecond vertical external-cavity surface-emitting laser in an Yb:YAG waveguide

Jornod¹,

Wittwer²,

Kränkel³

et al. 2017

Opt. Express

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We present the amplification of a mode-locked vertical external-cavity surface-emitting laser (VECSEL) using an Yb:YAG crystalline waveguide as gain medium. The VECSEL seed laser operates at a center wavelength of 1030 nm and generates 300-fs pulses at a repetition rate of 1.77 GHz. An average seed power of 60 mW was launched onto a 8.3 mm long fs-laser written Yb:YAG waveguide pumped by 7.7 W from a 969-nm continuous-wave VECSEL. The amplifier achieves an average output power of up to 2.9 W, corresponding to an amplification factor of 17 dB. Due to gain narrowing, the pulse duration increases to 629 fs. Our results show that crystalline waveguides are a promising technique for the realization of compact multi-watt ultrafast amplifier systems.

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Section: Resultsmentioning

confidence: 99%

Section: Yb:yag Waveguide Amplifiermentioning

confidence: 99%

High-power amplification of a femtosecond vertical external-cavity surface-emitting laser in an Yb:YAG waveguide

Jornod¹,

Wittwer²,

Kränkel³

et al. 2017

Opt. Express

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show abstract

“…Calculated gain cross sections (inversion level β 0.3) of the Yb-doped laser crystals YAG, LuO, and CALGO (σ-polarization).The corresponding FWHM gain bandwidths are given in parentheses. Data taken from Refs [17,18]…”

mentioning

confidence: 99%

Kerr lens mode-locked Yb:CALGO thin-disk laser

et al. 2018

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We demonstrate the first Kerr lens mode-locked Yb:CaGdAlO (Yb:CALGO) thin-disk laser oscillator. It generates pulses with a duration of 30 fs at a central wavelength of 1048 nm and a repetition rate of 124 MHz. The laser emits the shortest pulses generated by a thin-disk laser oscillator, equal to the shortest pulse duration obtained by Yb-doped bulk oscillators. The average output power is currently limited to 150 mW by the low gain and limited disk quality. We expect that more suitable Yb:CALGO disks will enable substantially higher power levels with similar pulse durations.

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“…Dielectric channel waveguide (WG) lasers are among the most promising technologies for compact and reliable laser sources, that combine multiwatt power levels with a high level of integration [1]. Major breakthroughs were achieved thanks to much progress in waveguide fabrication methods such as ionexchange [2], liquid-phase epitaxy [3], and femtosecond-laser (fs-laser) inscription [4][5][6]. In continuous wave (CW) operation, power levels of up to 5.1 W and slope efficiencies up to 73% were reported for fs-laser-inscribed channel waveguide lasers [5].…”

mentioning

confidence: 99%

“…We modified our previous WG writing scheme [5,6,10] by inserting a pinhole with 600 μm diameter into the beam path of the fslaser to improve the beam quality by mode cleaning. Because of the large distance between the pinhole and the aspheric focusing lens (f 3.1 mm, NA 0.68) used for the laser inscription, only the 0th order of the resulting diffraction pattern is transmitted through the aperture of this lens.…”

mentioning

confidence: 99%

Highly efficient Q-switched Yb:YAG channel waveguide laser with 56 W of average output power

et al. 2016

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In this Letter, we present high-power continuous wave (CW) and Q-switched femtosecond laser-written Yb: YAG channel waveguide lasers. In Q-switched operation, obtained by a semiconductor saturable absorber mirror (SESAM), as well as in CW operation, the laser generates average output powers of more than 5.6 W and reaches slope efficiencies above 74%. The Q-switched laser operated at a maximum repetition rate of 5.4 MHz with a minimum pulse duration of 11 ns, and with a maximum pulse energy of 1 μJ. This laser has almost an order of magnitude higher average output power than previously reported Q-switched channel waveguide lasers. Dielectric channel waveguide (WG) lasers are among the most promising technologies for compact and reliable laser sources, that combine multiwatt power levels with a high level of integration [1]. Major breakthroughs were achieved thanks to much progress in waveguide fabrication methods such as ionexchange [2], liquid-phase epitaxy [3], and femtosecond-laser (fs-laser) inscription [4][5][6]. In continuous wave (CW) operation, power levels of up to 5.1 W and slope efficiencies up to 73% were reported for fs-laser-inscribed channel waveguide lasers [5]. Several Q-switched and CW modelocked dielectric channel waveguide lasers were demonstrated, and pulse durations down to 285 fs were realized [7,8]. Q-switched operation was demonstrated with average output power levels of up to 680 mW [9].In this Letter, we demonstrate that the combination of femtosecond laser-written crystalline channel waveguides with semiconductor saturable absorber mirrors (SESAMs) enables the realization of a high-power Q-switched channel WG laser.We present the first Q-switched channel WG lasers with multiwatt average output power, achieving pulse energies of up to 1 μJ.The waveguiding microstructures were inscribed into a 7% Yb 3 -doped Y 3 Al 5 O 12 (Yb:YAG) crystal with a fs-laser. They consist of two parallel tracks, which are inscribed by a linear translation of the sample perpendicular to the incident fs-laser beam. These tracks exhibit distances between 22 and 30 μm. Owing to a stress-induced refractive index change, the waveguiding region is in the center between the tracks. Such waveguides are often referred to as type II waveguides [4,5]. Here, we superimposed the linear translation with a velocity of 25 μm/s of the sample with a sine oscillation with an oscillation amplitude of 2 to 4 μm and an oscillation frequency of 70 Hz; the fs-laser writing scheme can be seen in Fig. 1.With this writing scheme a larger refractive index change and a better confinement of the laser mode can be achieved [5]. We modified our previous WG writing scheme [5,6,10] by inserting a pinhole with 600 μm diameter into the beam path of the fslaser to improve the beam quality by mode cleaning. Because of the large distance between the pinhole and the aspheric focusing lens (f 3.1 mm, NA 0.68) used for the laser inscription, only the 0th order of the resulting diffraction pattern is transmitted through the aperture of this lens. The ...

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Efficient Yb^3+:CaGdAlO_4 bulk and femtosecond-laser-written waveguide lasers

Cited by 30 publications

References 20 publications

High-power amplification of a femtosecond vertical external-cavity surface-emitting laser in an Yb:YAG waveguide

High-power amplification of a femtosecond vertical external-cavity surface-emitting laser in an Yb:YAG waveguide

Kerr lens mode-locked Yb:CALGO thin-disk laser

Highly efficient Q-switched Yb:YAG channel waveguide laser with 56 W of average output power

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