Prof. Magnus Engholm Profile

Prof. Magnus Engholm

Senior Researcher at Mid Sweden Univ

SPIE Involvement:

Author

Publications (21)

Proceedings Article | 13 March 2024 Poster

Hydroxyl influences on silica fiber photonic heat engines

B. Meehan, T. Hawkins, M. Engholm, P. Dragic, J. Knall, M. J. Digonnet, J. Ballato

Proceedings Volume 12902, 1290207 (2024) https://doi.org/10.1117/12.3002616

KEYWORDS: Optical fibers, Ytterbium, Silica, Glasses, Fluorescence, Fiber lasers, Chemical composition, Spectroscopy, Quenching, Laser systems engineering

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Proceedings Article | 12 March 2024 Poster + Paper

Electrically conductive polymer-graphene composite material for selective laser sintering additive manufacturing

Luke Bond, Henrik Andersson, Jonas Örtegren, Magnus Larsson, Magnus Engholm

Proceedings Volume 12873, 1287317 (2024) https://doi.org/10.1117/12.3003049

KEYWORDS: Resistance, Composites, Laser sintering, Graphene, Electrical conductivity, Laser processing, Sintering, Scanning electron microscopy, Polymers, Particles

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Proceedings Article | 12 March 2024 Presentation + Paper

Laser-assisted processing of nano-graphite/silicon anode materials for improved performance of Li-ion batteries

Luke Bond, Henrik Andersson, Magnus Engholm

Proceedings Volume 12873, 128730J (2024) https://doi.org/10.1117/12.2691739

KEYWORDS: Silicon, Laser processing, Coating, Atmospheres, Anodes, Batteries, Scanning electron microscopy, Particles, Oxygen, Electrodes

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Proceedings Article | 12 March 2024 Presentation + Paper

Production of Yb:YVO4 nanoparticles by pulsed laser ablation in liquid using a femtosecond laser

Luke Bond, Ellinor Jönsson, Magnus Engholm

Proceedings Volume 12872, 128720C (2024) https://doi.org/10.1117/12.3002581

KEYWORDS: Nanoparticles, Crystals, Laser ablation, Liquids, Raman spectroscopy, Femtosecond phenomena, Pulsed laser operation, YAG lasers, Particles

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Proceedings Article | 15 March 2023 Presentation + Paper

Cooling Yb-doped silica fibers and fiber lasers using anti-Stokes pumping

Benjamin Frey, Enkeleda Balliu, Pierre-Baptiste Vigneron, Jenny Knall, Thomas Hawkins, Bailey Meehan, Mary Ann Cahoon, John Ballato, Magnus Engholm, Peter Dragic, Nanjie Yu, Tommy Boilard, Martin Bernier, Michel J. Digonnet

Proceedings Volume 12437, 1243707 (2023) https://doi.org/10.1117/12.2655634

KEYWORDS: Ytterbium, Quenching, Nanoparticles, Aluminum, Optical fibers, Fiber lasers, Temperature metrology, Silica, Fluorescence, Ions

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Proceedings Article | 15 March 2023 Open Access

Material approaches to thermal management in advanced fiber lasers and amplifiers

J. Ballato, T. Hawkins, P. Dragic, M. Engholm, M. J. Digonnet, L. Dong

Proceedings Volume 12437, 1243705 (2023) https://doi.org/10.1117/12.2655348

KEYWORDS: Glasses, Optical fibers, Silica, Thermodynamics, Quantum processes, Dopants, Chemical vapor deposition, Doping, Rayleigh scattering, Transverse mode instability

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Proceedings Article | 4 March 2022 Presentation + Paper

Anti-Stokes cooling in silica and nanoparticle-doped silicate fibers

Pierre-Baptiste Vigneron, Bailey Meehan, Mary Ann Cahoon, Thomas Hawkins, John Ballato, Peter Dragic, Magnus Engholm, Tommy Boilard, Martin Bernier, Michel J. Digonnet

Proceedings Volume 12018, 1201805 (2022) https://doi.org/10.1117/12.2615738

KEYWORDS: Optical fibers, Ytterbium, Ions, Heat treatments, Silica, Nanoparticles, Absorption, Fiber lasers, Temperature metrology, Luminescence

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The recent reports of laser cooling in Yb-doped aluminosilicate fibers and silica preforms have opened up the field of optical refrigeration and radiation-balanced lasers to the enormous realm of silica fiber lasers and amplifiers. To increase the cooling efficiency achieved in these materials, it is critical to identify host compositions that improve the Yb³⁺-ion properties in the directions of low concentration quenching, short radiative lifetime, and a long-wavelength absorption tail that extends as far as possible above the zero-phonon line. In this on-going quest, nanoparticle-doped fibers offer a promising technique to modify the chemical environment of the Yb³⁺ ions and achieve some of these properties. In this work, three fibers in which the Yb³⁺ ions are initially encapsulated in CaF_2, SrF_2, or BaF₂nanoparticles were fabricated using a solution-doping technique, and their laser-cooling properties evaluated experimentally and analyzed. The CaF₂ fiber and the SrF₂ fiber were successfully cooled at atmospheric pressure when pumped with a continuous-wave laser at the near-optimum wavelength of 1040 nm. The measured maximum temperature change from room temperature was -26.2 mK for the CaF₂ fiber at a pump power absorption level of 90 mW/m, and -16.7 mK at 66 mW/m for the SrF₂ fiber. The BaF₂ fiber did not cool, but it warmed only slightly, indicating that it was not far from cooling. Analysis of the measured dependence of the fiber temperature change on pump power with a model enabled extraction of the fiber’s critical quenching concentration and residual absorptive loss due to impurities. Comparison of these values to the values reported for an aluminosilicate fiber and fiber preforms that cooled shows that the CaF₂ and SrF₂ fibers faired as well as the fiber, and better than the preforms, in terms of quenching, but that they had a higher absorptive loss. This study establishes the significant research potential of nanoparticle-doped fibers in the search for efficient laser-cooling silica hosts.

Proceedings Article | 18 April 2021 Presentation

Highly doped multicomponent phosphate glass fibers for compact pulsed optical amplifiers

Nadia Giovanna Boetti, Diego Pugliese, Omri Moschovits, Enkeleda Balliu, Joris Lousteau, Duccio Gallichi-Nottiani, Davide Janner, Amiel Ishaaya, Magnus Engholm, Daniel Milanese

Proceedings Volume 11773, 117730N (2021) https://doi.org/10.1117/12.2590840

KEYWORDS: Glasses, Optical fibers, Optical amplifiers, Fiber amplifiers, Cladding, Oscillators, Optics manufacturing, LIDAR, Ions, Fiber lasers

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Proceedings Article | 5 March 2021 Presentation

Experimental demonstration of a cooled silica fiber amplifier

Jennifer Knall, Magnus Engholm, Tommy Boilard, Martin Bernier, Michel Digonnet

Proceedings Volume 11702, 1170209 (2021) https://doi.org/10.1117/12.2589941

KEYWORDS: Optical fibers, Fiber amplifiers, Optical amplifiers, Temperature metrology, Luminescence, Ions

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Proceedings Article | 3 March 2020 Presentation + Paper

Experimental observation of cooling in Yb-doped silica fibers

Jenny Knall, Pierre-Baptiste Vigneron, Magnus Engholm, Peter Dragic, Nanjie Yu, John Ballato, Martin Bernier, Michel Digonnet

Proceedings Volume 11298, 112980F (2020) https://doi.org/10.1117/12.2548506

KEYWORDS: Temperature metrology, Optical fibers, Fiber Bragg gratings, Silica, Ytterbium, ZBLAN, Luminescence, Absorption, Multimode fibers, Fiber lasers

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Proceedings Article | 7 March 2019 Paper

A compact, single-frequency, high-power, SBS-free, Yb-doped single-stage fiber amplifier

Enkeleda Balliu, Magnus Engholm, Hans-Erik Nilsson

Proceedings Volume 10896, 1089618 (2019) https://doi.org/10.1117/12.2511049

KEYWORDS: Fiber amplifiers, Oscillators, Absorption, Optical isolators, Diodes, Signal to noise ratio, Laser scattering, Cladding, Manufacturing, Ytterbium

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Proceedings Article | 14 March 2018 Presentation

A combined glucose and pH sensor on a single optical fiber for continuous point-of-care testing (Conference Presentation)

Krister Hammarling, Harald Muri, Markus Wahl, Magnus Engholm, Dag Hjelme

Proceedings Volume 10488, 104880A (2018) https://doi.org/10.1117/12.2290055

KEYWORDS: Glucose, Sensors, Point-of-care devices, In vivo imaging, Interferometers, Polymers, Optical fibers, Blood, Time metrology, Fiber optics sensors

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Proceedings Article | 14 March 2018 Presentation

Fabrication of transparent flexible electrodes by laser-assisted processing of flash light sintered gold nanoparticles on a polycarbonate filter membrane (Conference Presentation)

Renyun Zhang, Magnus Engholm, Håkan Olin

Proceedings Volume 10519, 1051917 (2018) https://doi.org/10.1117/12.2289117

KEYWORDS: Electrodes, Gold, Nanoparticles, Laser processing, Laser ablation, Solid state lasers, Optical lithography, Nanowires, Oxides, Sodium

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Proceedings Article | 18 March 2016 Paper

Laser-assisted reduction of graphene oxide for paper based large area flexible electronics

E. Balliu, H. Andersson, M. Engholm, S. Forsberg, H. Olin

Proceedings Volume 9736, 973610 (2016) https://doi.org/10.1117/12.2212474

KEYWORDS: Graphene, Oxides, FT-IR spectroscopy, Metals, Flexible circuits, Glasses, Laser systems engineering, Laser energy, Silver, Polymers

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Proceedings Article | 12 March 2015 Paper

Laser sintering of silver nano-particles inks printed on paper substrates

E. Balliu, H. Andersson, M. Hummelgård, H. Olin, M. Engholm

Proceedings Volume 9351, 935111 (2015) https://doi.org/10.1117/12.2078825

KEYWORDS: Laser sintering, Silver, Scanning electron microscopy, Printing, Continuous wave operation, Laser energy, Atomic force microscopy, Mirrors, Pulsed laser operation, Polymers

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Proceedings Article | 26 March 2014 Paper

Compact nanosecond pulsed single stage Yb-doped fiber amplifier

E. Balliu, M. Engholm, J. Hellström, G. Elgcrona, H. Karlsson

Proceedings Volume 8959, 895910 (2014) https://doi.org/10.1117/12.2040799

KEYWORDS: Fiber amplifiers, Phase modulation, Oscillators, Optical isolators, Molybdenum, Solid state lighting, Solid state lasers, Fiber lasers, Polarization, Pulsed laser operation

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Proceedings Article | 22 March 2013 Paper

Strong excited state absorption (ESA) in Yb-doped fiber lasers

Magnus Engholm, Sara Rydberg, Krister Hammarling

Proceedings Volume 8601, 86010P (2013) https://doi.org/10.1117/12.2002957

KEYWORDS: Absorption, Silica, Ultraviolet radiation, Luminescence, Ions, Cladding, Ytterbium, Photons, Near infrared, Semiconductor lasers

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Proceedings Article | 17 February 2010 Paper

Ytterbium-doped fibers co-doped with cerium: next generation of fibers for high power fiber lasers?

M. Engholm, L. Norin

Proceedings Volume 7580, 758008 (2010) https://doi.org/10.1117/12.847928

KEYWORDS: Cerium, Absorption, High power fiber lasers, Laser applications, Laser stabilization, Fiber lasers, Laser systems engineering, Current controlled current source, Ytterbium, Glasses

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