| 1. |
- Loiko, Pavel, et al.
(författare)
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Inkjet-Printing of Graphene Saturable Absorbers for similar to 2 mu m Bulk and Waveguide Lasers
- 2017
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Ingår i: 2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO). - : IEEE. - 9781943580279
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Konferensbidrag (refereegranskat)abstract
- We report on inkjet-printing of graphene saturable absorbers (SAs) suitable for passive Q-switching of similar to 2-mu m bulk and waveguide lasers. Using graphene-SA in a microchip Tm:KLu(WO4)(2) laser, 1.2 mu J/136 ns pulses are generated at 1917 nm.
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| 2. |
- Loiko, Pavel, et al.
(författare)
-
Inkjet-printing of graphene saturable absorbers for similar to 2 mu m bulk and waveguide lasers
- 2018
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Ingår i: Optical Materials Express. - : Optical Society of America. - 2159-3930 .- 2159-3930. ; 8:9, s. 2803-2814
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Tidskriftsartikel (refereegranskat)abstract
- A technique for inkjet-printing of graphene saturable absorbers (SAs) for similar to 2-mu m bulk and waveguide lasers is presented. Based on distillation-assisted solvent exchange to fabricate high-concentration graphene inks, this technique is capable of producing few-layer graphene films of arbitrary shape. Absorption saturation of graphene printed on glass is demonstrated at similar to 1.56 mu m for picosecond and femtosecond pulses indicating a large fraction of the saturable losses. Inkjet-printed transmission-type graphene SAs are applied in passively Q-switched nanosecond thulium (Tm) microchip and planar waveguide lasers. The Tm microchip laser generates 136 ns / 1.2 mu J pulses at 1917 nm with a repetition rate of 0.37 MHz with a Q-switching conversion efficiency reaching 65%. The planar waveguide laser generates 98 ns / 21 nJ pulses at 1834 nm at a repetition rate in the MHz-range. The inkjet-printing technique is promising for production of patterned SAs for waveguide lasers.
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| 3. |
- Loiko, Pavel, et al.
(författare)
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Oriented zinc oxide nanorods : A novel saturable absorber for lasers in the near-infrared
- 2018
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 9, s. 2730-2740
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Tidskriftsartikel (refereegranskat)abstract
- Zinc oxide (ZnO) nanorods (NRs) oriented along the crystallographic [001] axis are grown by the hydrothermal method on glass substrates. The ZnO NRs exhibit a broadband (1-2 mu m) near-IR absorption ascribed to the singly charged zinc vacancy V-z(n)-1. The saturable absorption of the ZnO NRs is studied at approximate to 1 mu m under picosecond excitation, revealing a low saturation intensity, approximate to 10 kW/cm(2), and high fraction of the saturable losses. The ZnO NRs are applied as saturable absorbers in diode-pumped Yb (approximate to 1.03 mu m) and Tm (approximate to 1.94 mu m) lasers generating nanosecond pulses. The ZnO NRs grown on various optical surfaces are promising broadband saturable absorbers for nanosecond near-IR lasers in bulk and waveguide geometries.
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| 4. |
- Yong, Yean-Sheng, et al.
(författare)
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Temperature-dependent absorption and emission of potassium double tungstates with high ytterbium content
- 2016
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 24:23, s. 26825-26837
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Tidskriftsartikel (refereegranskat)abstract
- We study the spectroscopic properties of thin films of potassium ytterbium gadolinium double tungstates, KYb0.57Gd0.43(WO4)(2), and potassium ytterbium lutetium double tungstates, KYb0.76Lu0.24(WO4)(2), specifically at the central absorption line near 981 nm wavelength, which is important for amplifiers and lasers. The absorption cross-section of both thin films is found to be similar to those of bulk potassium rare-earth double tungstates, suggesting that the crystalline layers retain their spectroscopic properties albeit having >50 at.% Yb3+ concentration. The influence of sample temperature is investigated and found to substantially affect the measured absorption cross-section. Since amplifiers and lasers typically operate above room temperature due to pump-induced heating, the temperature dependence of the peak-absorption cross-section of the KYb0.57Gd0.43(WO4)(2) is evaluated for the sample being heated from 20 degrees C to 170 degrees C, resulting in a measured reduction of peak-absorption cross-section at the transitions near 933 nm and 981 nm by similar to 40% and similar to 52%, respectively. It is shown that two effects, the change of Stark-level population and linewidth broadening due to intra-manifold relaxation induced by temperature-dependent electronphonon interaction, contribute to the observed behavior. The effective emission cross-sections versus temperature have been calculated. Luminescence-decay measurements show no significant dependence of the luminescence lifetime on temperature.
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