On the efficiency of Tm-doped 2-µm lasers

Koop van Dalfsen, S. Aravazhi, C. Grivas, Sonia Maria García Blanco, Markus Pollnau

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic

    Abstract

    A potassium double tungstate layer with the composition KY0.40Gd0.29Lu0.23Tm0.08(WO4)2 was grown onto a pure KY(WO4)2 substrate by liquid-phase epitaxy, microstructured by standard lithography and Ar-ion etching, and overgrown by a pure KY(WO4)2 layer. The end-facets were polished. Laser experiments were performed on these buried, ridge-type channel waveguides in a resonator with one butt-coupled mirror and Fresnel reflection from the other end-facet, resulting in a high output-coupling degree of 89%, compared to intrinsic round-trip losses of only 2%. By pumping with a Ti:Sapphire laser at 794 nm, 1.6 W of output power at 1.84 μm with a maximum slope efficiency of ~80% was obtained. To the best of our knowledge, this result represents the most efficient 2-μm channel waveguide laser to date. We determined the optimum Tm3+ concentration in double tungstate channel waveguides to be at least 8at.% for efficient lasing. The theoretical limit of the slope efficiency depends on the Stokes efficiency which here is 43.2%, the outcoupling efficiency which here is 99%, and the pump quantum efficiency. The pump quantum efficiency of a 2-µm Tm3+ laser pumped around 800 nm hinges on the efficiency of its cross-relaxation process. By fitting the macroscopic cross-relaxation parameter which linearly depends on the Tm3+ concentration to concentration-dependent luminescence-decay data, calculating the overall decay rate of the pump level, and deriving the concentration-dependent pump quantum efficiency, we obtain a theoretical limit for the slope efficiency of 83% for the chosen Tm3+ concentration. The experimental slope efficiency of ~80% closely approaches this limit.
    Original languageUndefined
    Title of host publicationSolid State Lasers XXIV
    Place of PublicationBellingham, USA
    PublisherSPIE
    PagesPaper 93421U
    Number of pages6
    ISBN (Print)978-1-62841-432-5
    DOIs
    Publication statusPublished - Apr 2015
    EventSolid State Lasers XXIV 2015 - San Francisco, United States
    Duration: 6 Feb 201512 Feb 2015
    Conference number: 24

    Publication series

    NameProceedings of the SPIE
    PublisherSPIE
    Volume9342

    Conference

    ConferenceSolid State Lasers XXIV 2015
    CountryUnited States
    CitySan Francisco
    Period6/02/1512/02/15

    Keywords

    • slope efficiency
    • EWI-25964
    • IOMS-APD: Active Photonic Devices
    • 2-µm laser
    • IR-95790
    • Potassium double tungstate
    • thulium laser
    • cross-relaxation process
    • METIS-312573
    • Waveguide laser

    Cite this

    van Dalfsen, K., Aravazhi, S., Grivas, C., García Blanco, S. M., & Pollnau, M. (2015). On the efficiency of Tm-doped 2-µm lasers. In Solid State Lasers XXIV (pp. Paper 93421U). (Proceedings of the SPIE; Vol. 9342). Bellingham, USA: SPIE. https://doi.org/10.1117/12.2077490
    van Dalfsen, Koop ; Aravazhi, S. ; Grivas, C. ; García Blanco, Sonia Maria ; Pollnau, Markus. / On the efficiency of Tm-doped 2-µm lasers. Solid State Lasers XXIV. Bellingham, USA : SPIE, 2015. pp. Paper 93421U (Proceedings of the SPIE).
    @inproceedings{4603ef0346ac4fbca240b5127388520e,
    title = "On the efficiency of Tm-doped 2-µm lasers",
    abstract = "A potassium double tungstate layer with the composition KY0.40Gd0.29Lu0.23Tm0.08(WO4)2 was grown onto a pure KY(WO4)2 substrate by liquid-phase epitaxy, microstructured by standard lithography and Ar-ion etching, and overgrown by a pure KY(WO4)2 layer. The end-facets were polished. Laser experiments were performed on these buried, ridge-type channel waveguides in a resonator with one butt-coupled mirror and Fresnel reflection from the other end-facet, resulting in a high output-coupling degree of 89{\%}, compared to intrinsic round-trip losses of only 2{\%}. By pumping with a Ti:Sapphire laser at 794 nm, 1.6 W of output power at 1.84 μm with a maximum slope efficiency of ~80{\%} was obtained. To the best of our knowledge, this result represents the most efficient 2-μm channel waveguide laser to date. We determined the optimum Tm3+ concentration in double tungstate channel waveguides to be at least 8at.{\%} for efficient lasing. The theoretical limit of the slope efficiency depends on the Stokes efficiency which here is 43.2{\%}, the outcoupling efficiency which here is 99{\%}, and the pump quantum efficiency. The pump quantum efficiency of a 2-µm Tm3+ laser pumped around 800 nm hinges on the efficiency of its cross-relaxation process. By fitting the macroscopic cross-relaxation parameter which linearly depends on the Tm3+ concentration to concentration-dependent luminescence-decay data, calculating the overall decay rate of the pump level, and deriving the concentration-dependent pump quantum efficiency, we obtain a theoretical limit for the slope efficiency of 83{\%} for the chosen Tm3+ concentration. The experimental slope efficiency of ~80{\%} closely approaches this limit.",
    keywords = "slope efficiency, EWI-25964, IOMS-APD: Active Photonic Devices, 2-µm laser, IR-95790, Potassium double tungstate, thulium laser, cross-relaxation process, METIS-312573, Waveguide laser",
    author = "{van Dalfsen}, Koop and S. Aravazhi and C. Grivas and {Garc{\'i}a Blanco}, {Sonia Maria} and Markus Pollnau",
    note = "10.1117/12.2077490",
    year = "2015",
    month = "4",
    doi = "10.1117/12.2077490",
    language = "Undefined",
    isbn = "978-1-62841-432-5",
    series = "Proceedings of the SPIE",
    publisher = "SPIE",
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    van Dalfsen, K, Aravazhi, S, Grivas, C, García Blanco, SM & Pollnau, M 2015, On the efficiency of Tm-doped 2-µm lasers. in Solid State Lasers XXIV. Proceedings of the SPIE, vol. 9342, SPIE, Bellingham, USA, pp. Paper 93421U, Solid State Lasers XXIV 2015, San Francisco, United States, 6/02/15. https://doi.org/10.1117/12.2077490

    On the efficiency of Tm-doped 2-µm lasers. / van Dalfsen, Koop; Aravazhi, S.; Grivas, C.; García Blanco, Sonia Maria; Pollnau, Markus.

    Solid State Lasers XXIV. Bellingham, USA : SPIE, 2015. p. Paper 93421U (Proceedings of the SPIE; Vol. 9342).

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic

    TY - GEN

    T1 - On the efficiency of Tm-doped 2-µm lasers

    AU - van Dalfsen, Koop

    AU - Aravazhi, S.

    AU - Grivas, C.

    AU - García Blanco, Sonia Maria

    AU - Pollnau, Markus

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    N2 - A potassium double tungstate layer with the composition KY0.40Gd0.29Lu0.23Tm0.08(WO4)2 was grown onto a pure KY(WO4)2 substrate by liquid-phase epitaxy, microstructured by standard lithography and Ar-ion etching, and overgrown by a pure KY(WO4)2 layer. The end-facets were polished. Laser experiments were performed on these buried, ridge-type channel waveguides in a resonator with one butt-coupled mirror and Fresnel reflection from the other end-facet, resulting in a high output-coupling degree of 89%, compared to intrinsic round-trip losses of only 2%. By pumping with a Ti:Sapphire laser at 794 nm, 1.6 W of output power at 1.84 μm with a maximum slope efficiency of ~80% was obtained. To the best of our knowledge, this result represents the most efficient 2-μm channel waveguide laser to date. We determined the optimum Tm3+ concentration in double tungstate channel waveguides to be at least 8at.% for efficient lasing. The theoretical limit of the slope efficiency depends on the Stokes efficiency which here is 43.2%, the outcoupling efficiency which here is 99%, and the pump quantum efficiency. The pump quantum efficiency of a 2-µm Tm3+ laser pumped around 800 nm hinges on the efficiency of its cross-relaxation process. By fitting the macroscopic cross-relaxation parameter which linearly depends on the Tm3+ concentration to concentration-dependent luminescence-decay data, calculating the overall decay rate of the pump level, and deriving the concentration-dependent pump quantum efficiency, we obtain a theoretical limit for the slope efficiency of 83% for the chosen Tm3+ concentration. The experimental slope efficiency of ~80% closely approaches this limit.

    AB - A potassium double tungstate layer with the composition KY0.40Gd0.29Lu0.23Tm0.08(WO4)2 was grown onto a pure KY(WO4)2 substrate by liquid-phase epitaxy, microstructured by standard lithography and Ar-ion etching, and overgrown by a pure KY(WO4)2 layer. The end-facets were polished. Laser experiments were performed on these buried, ridge-type channel waveguides in a resonator with one butt-coupled mirror and Fresnel reflection from the other end-facet, resulting in a high output-coupling degree of 89%, compared to intrinsic round-trip losses of only 2%. By pumping with a Ti:Sapphire laser at 794 nm, 1.6 W of output power at 1.84 μm with a maximum slope efficiency of ~80% was obtained. To the best of our knowledge, this result represents the most efficient 2-μm channel waveguide laser to date. We determined the optimum Tm3+ concentration in double tungstate channel waveguides to be at least 8at.% for efficient lasing. The theoretical limit of the slope efficiency depends on the Stokes efficiency which here is 43.2%, the outcoupling efficiency which here is 99%, and the pump quantum efficiency. The pump quantum efficiency of a 2-µm Tm3+ laser pumped around 800 nm hinges on the efficiency of its cross-relaxation process. By fitting the macroscopic cross-relaxation parameter which linearly depends on the Tm3+ concentration to concentration-dependent luminescence-decay data, calculating the overall decay rate of the pump level, and deriving the concentration-dependent pump quantum efficiency, we obtain a theoretical limit for the slope efficiency of 83% for the chosen Tm3+ concentration. The experimental slope efficiency of ~80% closely approaches this limit.

    KW - slope efficiency

    KW - EWI-25964

    KW - IOMS-APD: Active Photonic Devices

    KW - 2-µm laser

    KW - IR-95790

    KW - Potassium double tungstate

    KW - thulium laser

    KW - cross-relaxation process

    KW - METIS-312573

    KW - Waveguide laser

    U2 - 10.1117/12.2077490

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    M3 - Conference contribution

    SN - 978-1-62841-432-5

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    BT - Solid State Lasers XXIV

    PB - SPIE

    CY - Bellingham, USA

    ER -

    van Dalfsen K, Aravazhi S, Grivas C, García Blanco SM, Pollnau M. On the efficiency of Tm-doped 2-µm lasers. In Solid State Lasers XXIV. Bellingham, USA: SPIE. 2015. p. Paper 93421U. (Proceedings of the SPIE). https://doi.org/10.1117/12.2077490