Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals

P.J. Hardman, W.A. Clarkson, G.J. Friel, Markus Pollnau, D.C. Hanna

    • 133 Citations

    Abstract

    Thermal lensing in an end-pumped Nd:YLF rod, under lasing and nonlasing conditions, has been investigated. Under lasing conditions, a weak thermal lens, with dioptric power varying linearly with pump power, was observed. Under nonlasing conditions, where higher inversion densities were involved, hence relevant to Q-switched operation or operation as an amplifier, a much stronger thermal lens was measured, whose power increased nonlinearly with pump power. This difference has been attributed to the increased heat deposition due to the subsequent multiphonon decay following various interionic upconversion processes, which increase strongly under nonlasing conditions, and is further exacerbated by the unfavorable temperature dependencies of heat conductivity and the rate of change of the refractive index with temperature. A strategy for reducing upconversion and its associated thermal loading, without degrading laser performance, is discussed.
    Original languageUndefined
    Pages (from-to)647-655
    Number of pages9
    JournalIEEE journal of quantum electronics
    Volume35
    Issue number4
    DOIs
    StatePublished - 1999

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    Lenses
    Pumps
    Temperature
    Thermal conductivity
    Refractive index
    Lasers

    Keywords

    • IOMS-APD: Active Photonic Devices
    • Lasers
    • neodymium:solid-state lasers
    • laser amplifiers
    • IR-70101
    • EWI-17567
    • Diode pumped lasers
    • Upconversion
    • laser thermal factors

    Cite this

    Hardman, P. J., Clarkson, W. A., Friel, G. J., Pollnau, M., & Hanna, D. C. (1999). Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals. IEEE journal of quantum electronics, 35(4), 647-655. DOI: 10.1109/3.753670

    Hardman, P.J.; Clarkson, W.A.; Friel, G.J.; Pollnau, Markus; Hanna, D.C. / Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals.

    In: IEEE journal of quantum electronics, Vol. 35, No. 4, 1999, p. 647-655.

    Research output: Scientific - peer-reviewArticle

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    title = "Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals",
    abstract = "Thermal lensing in an end-pumped Nd:YLF rod, under lasing and nonlasing conditions, has been investigated. Under lasing conditions, a weak thermal lens, with dioptric power varying linearly with pump power, was observed. Under nonlasing conditions, where higher inversion densities were involved, hence relevant to Q-switched operation or operation as an amplifier, a much stronger thermal lens was measured, whose power increased nonlinearly with pump power. This difference has been attributed to the increased heat deposition due to the subsequent multiphonon decay following various interionic upconversion processes, which increase strongly under nonlasing conditions, and is further exacerbated by the unfavorable temperature dependencies of heat conductivity and the rate of change of the refractive index with temperature. A strategy for reducing upconversion and its associated thermal loading, without degrading laser performance, is discussed.",
    keywords = "IOMS-APD: Active Photonic Devices, Lasers, neodymium:solid-state lasers, laser amplifiers, IR-70101, EWI-17567, Diode pumped lasers, Upconversion, laser thermal factors",
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    Hardman, PJ, Clarkson, WA, Friel, GJ, Pollnau, M & Hanna, DC 1999, 'Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals' IEEE journal of quantum electronics, vol 35, no. 4, pp. 647-655. DOI: 10.1109/3.753670

    Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals. / Hardman, P.J.; Clarkson, W.A.; Friel, G.J.; Pollnau, Markus; Hanna, D.C.

    In: IEEE journal of quantum electronics, Vol. 35, No. 4, 1999, p. 647-655.

    Research output: Scientific - peer-reviewArticle

    TY - JOUR

    T1 - Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals

    AU - Hardman,P.J.

    AU - Clarkson,W.A.

    AU - Friel,G.J.

    AU - Pollnau,Markus

    AU - Hanna,D.C.

    PY - 1999

    Y1 - 1999

    N2 - Thermal lensing in an end-pumped Nd:YLF rod, under lasing and nonlasing conditions, has been investigated. Under lasing conditions, a weak thermal lens, with dioptric power varying linearly with pump power, was observed. Under nonlasing conditions, where higher inversion densities were involved, hence relevant to Q-switched operation or operation as an amplifier, a much stronger thermal lens was measured, whose power increased nonlinearly with pump power. This difference has been attributed to the increased heat deposition due to the subsequent multiphonon decay following various interionic upconversion processes, which increase strongly under nonlasing conditions, and is further exacerbated by the unfavorable temperature dependencies of heat conductivity and the rate of change of the refractive index with temperature. A strategy for reducing upconversion and its associated thermal loading, without degrading laser performance, is discussed.

    AB - Thermal lensing in an end-pumped Nd:YLF rod, under lasing and nonlasing conditions, has been investigated. Under lasing conditions, a weak thermal lens, with dioptric power varying linearly with pump power, was observed. Under nonlasing conditions, where higher inversion densities were involved, hence relevant to Q-switched operation or operation as an amplifier, a much stronger thermal lens was measured, whose power increased nonlinearly with pump power. This difference has been attributed to the increased heat deposition due to the subsequent multiphonon decay following various interionic upconversion processes, which increase strongly under nonlasing conditions, and is further exacerbated by the unfavorable temperature dependencies of heat conductivity and the rate of change of the refractive index with temperature. A strategy for reducing upconversion and its associated thermal loading, without degrading laser performance, is discussed.

    KW - IOMS-APD: Active Photonic Devices

    KW - Lasers

    KW - neodymium:solid-state lasers

    KW - laser amplifiers

    KW - IR-70101

    KW - EWI-17567

    KW - Diode pumped lasers

    KW - Upconversion

    KW - laser thermal factors

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    M3 - Article

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    Hardman PJ, Clarkson WA, Friel GJ, Pollnau M, Hanna DC. Energy-transfer upconversion and thermal lensing in high-power end-pumped Nd:YLF laser crystals. IEEE journal of quantum electronics. 1999;35(4):647-655. Available from, DOI: 10.1109/3.753670