Dr. Constantin L. Häfner Profile

Dr. Constantin L. Häfner

Managing Director at Fraunhofer-ILT

SPIE Involvement:

Track Chair | Author | Editor

Publications (23)

Proceedings Article | 13 March 2024 Presentation + Paper

Presentation + Paper

Optical setup for a two-dimensional tweezer array with independently adjustable columns for neutral atom quantum computing

Martin Adams, Martin Traub, Hans-Dieter Hoffmann, Florian Meinert, Philipp Ilzhöfer, Thomas Westphalen, Kersten Ludwig, Jiachen Zhao, Achim Scholz, Govind Unnikrishnan, Ratnesh Kumar Gupta, Tilman Pfau, Constantin Haefner

Proceedings Volume 12911, 129110L (2024) https://doi.org/10.1117/12.2692620

KEYWORDS: Mirrors, Chemical species, Relays, Quantum computing, Quantum computers, Quantum channels, Optical path differences, Imaging systems, Imaging arrays, Lens arrays

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Proceedings Article | 8 June 2023 Presentation

Presentation

Highly efficient nonlinear spectral broadening of mJ pulses at 2µm wavelength in a gas multipass cell and compression sub-30 fs (Conference Presentation)

Lucas Eisenbach, Peter Rußbüldt, Jan Schulte, Rudolf Meyer, Tobias Heuermann, Ziyao Wang, Mathias Lenski, Philipp Gierschke, Jens Limpert, Constantin Häfner

Proceedings Volume PC12577, PC125770E (2023) https://doi.org/10.1117/12.2669583

KEYWORDS: Ultrafast phenomena, Relative intensity noise, Pulse signals, Laser systems engineering, Silica, Short wave infrared radiation, Quality systems, Krypton, High harmonic generation, Helium

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Proceedings Article | 15 March 2023 Presentation + Paper

Presentation + Paper

In situ synchrotron observation of the vapor capillary geometry in laser welding of copper with 1030 nm and 515 nm laser beam sources

Marc Hummel, Christian Meier, Alexander Olowinsky, Arnold Gillner, Felix Beckmann, Julian Moosmann, Constantin Häfner

Proceedings Volume 12414, 124140A (2023) https://doi.org/10.1117/12.2648946

KEYWORDS: Capillaries, Porosity, Copper, Synchrotrons, Laser welding, Image processing, Laser radiation, Reflection, Scintillators, Light absorption

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Proceedings Article | 15 March 2023 Presentation + Paper

Presentation + Paper

Influence of ring-shaped laser beam during welding of AW-5083 and AW-6082

S. Hollatz, M. Hummel, M. Lach, A. Olowinsky, A. Gillner, C. Häfner, F. Beckmann, J. Moosmann

Proceedings Volume 12414, 124140C (2023) https://doi.org/10.1117/12.2649092

KEYWORDS: Solids, Bubbles, Laser welding, X-rays, Aluminum, Capillaries, Alloys, Scintillators, Ring lasers, Modulation

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Proceedings Article | 14 March 2023 Presentation + Paper

Presentation + Paper

Highly reliable diode laser pump sources for the space qualified MERLIN laser platform and future wind LiDAR missions

Martin Traub, Stephan Wissenberg, Thomas Westphalen, Sarah Klein, Jana Ammersbach, Marie Livrozet, Bastian Gronloh, Dominik Esser, Martin Giesberts, Heinrich Faidel, Dominik Mohr, Hans-Dieter Hoffmann, Constantin Haefner

Proceedings Volume 12403, 124030A (2023) https://doi.org/10.1117/12.2657282

KEYWORDS: Semiconductor lasers, Oscillators, LIDAR, Laser radiation, Laser development, Fiber coupled lasers, Methane, Fiber lasers, Fiber couplers, Transmitters

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Proceedings Article | 14 March 2023 Presentation + Paper

Presentation + Paper

Industry and academia: pursuing a PhD at Fraunhofer, the best of both worlds

Sarah Klein, Martin Adams, Martin Traub, Tim Biermann, Hans-Dieter Hoffmann, Constantin Haefner

Proceedings Volume 12401, 124010B (2023) https://doi.org/10.1117/12.2664343

KEYWORDS: Semiconductor lasers, Industry, Optical simulations, Laser welding, Laser applications, High power lasers, Thermography, Quantum processes, Laser development, Engineering

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Proceedings Article | 4 March 2022 Presentation + Paper

Presentation + Paper

Evaluation of productivity scaling approaches for laser powder bed fusion of nickel-base alloy 625

Tim Lantzsch, Daniel Heussen, Niklas Praetzsch, Constantin Haefner

Proceedings Volume 11994, 1199405 (2022) https://doi.org/10.1117/12.2611151

KEYWORDS: Laser processing, Fiber lasers, 3D scanning, Laser scanners, Optical testing, Optical scanning systems, Calibration, Collimators, Laser welding, Single mode fibers, 3D printing, Additive manufacturing

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Proceedings Article | 2 March 2022 Presentation + Paper

Presentation + Paper

Frequency down-conversion for efficient, low-noise quantum frequency converters

Jan Fabian Geus, Florian Elsen, Sebastian Nyga, Bernd Jungbluth, Hans-Dieter Hoffmann, Constantin Haefner

Proceedings Volume 12015, 1201506 (2022) https://doi.org/10.1117/12.2607750

KEYWORDS: Quantum communications, Photons, Crystals, Quantum networks, Waveguides, Frequency converters, Telecommunications, Laser crystals, Quantum efficiency, Frequency conversion

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Proceedings Article | 19 November 2021 Presentation + Paper

Presentation + Paper

Detection of contamination of protective windows in Laser Powder Bed Fusion by means of a line scan camera

Niklas Praetzsch, Hermann Sturzebecher, Norbert Pirch, Felix Fischer, Constantin Haefner

Proceedings Volume 11910, 1191015 (2021) https://doi.org/10.1117/12.2598589

KEYWORDS: Contamination, Particles, Line scan cameras, Imaging systems, Metals, Image processing, Laser induced damage, Line scan image sensors, Laser welding, Manufacturing, Additive manufacturing, Laser manufacturing, Laser optics, Silicate glass

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Proceedings Article | 18 April 2021 Presentation

Presentation

Welcome and Introduction to SPIE Conference 11777

Joachim Hein, Thomas Butcher, Pavel Bakule, Constantin Haefner, Georg Korn, Luis Silva

Proceedings Volume 11777, 1177702 (2021) https://doi.org/10.1117/12.2595257

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Proceedings Article | 5 March 2021 Poster + Presentation

Poster + Presentation

Towards imaging with undetected photons with a nonlinear Mach-Zehnder-type interferometer in MIR

Florian Herbst, Florian Elsen, Bernd Jungbluth, Hans-Dieter Hoffmann, Constantin Häfner

Proceedings Volume 11670, 116701I (2021) https://doi.org/10.1117/12.2578639

KEYWORDS: Photons, Nonlinear crystals, Interferometers, Crystals, Near infrared, Laser crystals, Absorption, Visible radiation, Silicon, Sensors

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Proceedings Article | 5 March 2021 Presentation

Presentation

Welcome and Introduction to SPIE Conference 11666

Abdul A. Awwal, Constantin Haefner

Proceedings Volume 11666, 1166602 (2021) https://doi.org/10.1117/12.2592465

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Proceedings Article | 26 April 2019 Paper

Paper

Scaling of petawatt-class lasers to multi-kHZ repetition rates

T. Galvin, A. Bayramian, K. Chesnut, A. Erlandson, C. Siders, E. Sistrunk, T. Spinka, C. Haefner

Proceedings Volume 11033, 1103303 (2019) https://doi.org/10.1117/12.2520981

KEYWORDS: Optical amplifiers, Amplifiers, Diodes, Laser development, High power lasers

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Proceedings Article | 26 April 2019 Paper

Paper

Laser Technology Development for High Peak Power Lasers Achieving Kilowatt Average Power and Beyond

E. Sistrunk, D. Alessi, A. Bayramian, K. Chesnut, A. Erlandson, T. Galvin, D. Gibson, H. Nguyen, B. Reagan, K. Schaffers, C. Siders, T. Spinka, C. Haefner

Proceedings Volume 11034, 1103407 (2019) https://doi.org/10.1117/12.2525380

KEYWORDS: High power lasers, Particle beams, Laser applications, Pulsed laser operation, Laser development, Laser systems engineering, Diodes, Amplifiers, Spatial filters, Optical amplifiers, Fusion energy

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Proceedings Article | 26 April 2019 Paper

Paper

Temporal pre-pulse generation in high-intensity CPA lasers from imperfect domain orientation in anisotropic crystals

Josef Cupal, Thomas Spinka, Emily Sistrunk, Bedrich Rus, Constantin Haefner

Proceedings Volume 11034, 110340F (2019) https://doi.org/10.1117/12.2524115

KEYWORDS: Crystals, Amplifiers, Polarization, Optical amplifiers, Laser crystals, Laser systems engineering, Pulsed laser operation

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Proceedings Article | 7 September 2018 Paper

Paper

Active learning with deep Bayesian neural network for laser control

Thomas Galvin, Sandrine Herriot, Brenda Ng, Wade Williams, Sachin Talathi, Thomas Spinka, Emily Sistrunk, Craig Siders, Constantin Haefner

Proceedings Volume 10751, 107510N (2018) https://doi.org/10.1117/12.2324364

KEYWORDS: Data modeling, Neural networks, Laser safety, Performance modeling, Machine learning, Amplifiers, Systems modeling, Pulsed laser operation

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Proceedings Article | 26 June 2017 Open Access

Open Access

Paper

High average power, diode pumped petawatt laser systems: a new generation of lasers enabling precision science and commercial applications

C. Haefner, A. Bayramian, S. Betts, R. Bopp, S. Buck, J. Cupal, M. Drouin, A. Erlandson, J. Horáček, J. Horner, J. Jarboe, K. Kasl, D. Kim, E. Koh, L. Koubíková, W. Maranville, C. Marshall, D. Mason, J. Menapace, P. Miller, P. Mazurek, A. Naylon, J. Novák, D. Peceli, P. Rosso, K. Schaffers, E. Sistrunk, D. Smith, T. Spinka, J. Stanley, R. Steele, C. Stolz, T. Suratwala, S. Telford, J. Thoma, D. VanBlarcom, J. Weiss, P. Wegner

Proceedings Volume 10241, 1024102 (2017) https://doi.org/10.1117/12.2281050

KEYWORDS: Laser applications, Laser systems engineering, Pulsed laser operation, Amplifiers, Semiconductor lasers, Diodes, Laser energy, Laser development, Physics, Positron emission tomography

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Proceedings Article | 26 June 2017 Presentation + Paper

Presentation + Paper

ELI-beamlines: progress in development of next generation short-pulse laser systems

B. Rus, P. Bakule, D. Kramer, J. Naylon, J. Thoma, M. Fibrich, J. Green, J. C. Lagron, R. Antipenkov, J. Bartoníček, F. Batysta, R. Baše, R. Boge, S. Buck, J. Cupal, M. A. Drouin, M. Ďurák, B. Himmel, T. Havlíček, P. Homer, A. Honsa, M. Horáček, P. Hríbek, J Hubáček, Z. Hubka, G. Kalinchenko, K. Kasl, L. Indra, P. Korous, M. Košelja, L. Koubíková, M. Laub, T. Mazanec, A. Meadows, J. Novák, D. Peceli, J. Polan, D. Snopek, V. Šobr, P. Trojek, B. Tykalewicz, P. Velpula, E. Verhagen, Š. Vyhlídka, J. Weiss, C. Haefner, A. Bayramian, S. Betts, A. Erlandson, J. Jarboe, G. Johnson, J. Horner, D. Kim, E. Koh, C. Marshall, D. Mason, E. Sistrunk, D. Smith, T. Spinka, J. Stanley, C. Stolz, T. Suratwala, S. Telford, T. Ditmire, E. Gaul, M. Donovan, C. Frederickson, G. Friedman, D. Hammond, D. Hidinger, G. Chériaux, A. Jochmann, M. Kepler, C. Malato, M. Martinez, T. Metzger, M. Schultze, P. Mason, K. Ertel, A. Lintern, C. Edwards, C. Hernandez-Gomez, J. Collier

Proceedings Volume 10241, 102410J (2017) https://doi.org/10.1117/12.2269818

KEYWORDS: Laser systems engineering, Optical amplifiers, Pulsed laser operation, Semiconductor lasers, Laser development, Laser applications, Cryogenics, Oscillators, Amplifiers, Picosecond phenomena

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Proceedings Article | 23 February 2017 Paper

Paper

Status of NIF laser and high power laser research at LLNL

Mark Bowers, Jeff Wisoff, Mark Herrmann, Tom Anklam, Jay Dawson, Jean-Michel Di Nicola, Constantin Haefner, Mark Hermann, Doug Larson, Chris Marshall, Bruno Van Wonterghem, Paul Wegner

Proceedings Volume 10084, 1008403 (2017) https://doi.org/10.1117/12.2257571

KEYWORDS: National Ignition Facility, High power lasers, Pulsed laser operation, Laser welding, Fusion energy, Physics, Fiber lasers, Radiography, Laser development, Picosecond phenomena, X-rays, Laser optics

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Proceedings Article | 23 November 2015 Paper

Paper

Test station development for laser-induced optical damage performance of broadband multilayer dielectric coatings

K. R. P. Kafka, E. A. Chowdhury, R. Negres, C. Stolz, J. Bude, A. Bayramian, C. Marshall, T. Spinka, C. Haefner

Proceedings Volume 9632, 96321C (2015) https://doi.org/10.1117/12.2195786

KEYWORDS: Raster graphics, Optical coatings, Laser development, Laser induced damage, Dielectrics, Multilayers, Manufacturing, Cameras, Laser systems engineering, Picosecond phenomena

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Proceedings Article | 12 May 2015 Paper

Paper

ELI-Beamlines: development of next generation short-pulse laser systems

B. Rus, P. Bakule, D. Kramer, J. Naylon, J. Thoma, J. Green, R. Antipenkov, M. Fibrich, J. Novák, F. Batysta, T. Mazanec, M. Drouin, K. Kasl, R. Baše, D. Peceli, L. Koubíková, P. Trojek, R. Boge, J. Lagron, Š. Vyhlídka, J. Weiss, J, Cupal, J. Hřebíček, P. Hříbek, M. Durák, J. Polan, M. Košelja, G. Korn, M. Horáček, J. Horáček, B. Himmel, T. Havlíček, A. Honsa, P. Korouš, M. Laub, C. Haefner, A. Bayramian, T. Spinka, C. Marshall, G. Johnson, S. Telford, J. Horner, B. Deri, T. Metzger, M. Schultze, P. Mason, K. Ertel, A. Lintern, J. Greenhalgh, C. Edwards, C. Hernandez-Gomez, J. Collier, T, Ditmire, E. Gaul, M. Martinez, C. Frederickson, D. Hammond, C. Malato, W. White, J. Houžvička

Proceedings Volume 9515, 95150F (2015) https://doi.org/10.1117/12.2184996

KEYWORDS: Optical amplifiers, Amplifiers, Pulsed laser operation, Picosecond phenomena, Oscillators, Semiconductor lasers, Crystals, Laser systems engineering, Diagnostics, Laser applications

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Proceedings Article | 26 February 2015 Paper

Paper

The commissioning of the advanced radiographic capability laser system: experimental and modeling results at the main laser output

J. M. Di Nicola, S. Yang, C. Boley, John Crane, J. Heebner, Thomas Spinka, P. Arnold, C. P. Barty, M. Bowers, T. Budge, K. Christensen, J. Dawson, G. Erbert, E. Feigenbaum, G. Guss, C. Haefner, M. Hermann, Doug Homoelle, J. Jarboe, J. Lawson, R. Lowe-Webb, Kathleen McCandless, Brent McHale, L. Pelz, P. Pham, M. Prantil, M. Rehak, M. Rever, Michael Rushford, R. Sacks, M. Shaw, D. Smauley, L. Smith, R. Speck, G. Tietbohl, P. Wegner, C. Widmayer

Proceedings Volume 9345, 93450I (2015) https://doi.org/10.1117/12.2080459

KEYWORDS: National Ignition Facility, Near field, Mirrors, Diagnostics, Picosecond phenomena, X-rays, Optical amplifiers, Performance modeling, Sensors, Fusion energy

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Proceedings Article | 26 February 2015 Paper

Paper

Optical damage performance measurements of multilayer dielectric gratings for high energy short pulse lasers

D. Alessi, C. Carr, R. Negres, R. Hackel, K. Stanion, D. Cross, G. Guss, J. Nissen, R. Luthi, James Fair, J. Britten, C. Haefner

Proceedings Volume 9345, 934509 (2015) https://doi.org/10.1117/12.2084823

KEYWORDS: Picosecond phenomena, Laser induced damage, Pulsed laser operation, Raster graphics, Laser energy, National Ignition Facility, Dielectrics, Diffraction gratings, Laser systems engineering, Laser damage threshold

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Showing 5 of 23 publications

Proceedings Volume Editor (6)

SPIE Conference Volume | 12 July 2023

High-power, High-energy Lasers and Ultrafast Optical Technologies

SPIE Conference Volume | 30 March 2023

High Power Lasers for Fusion Research VII

SPIE Conference Volume | 7 May 2021

High Power Lasers and Applications

SPIE Conference Volume | 22 April 2021

High Power Lasers for Fusion Research VI

SPIE Conference Volume | 17 June 2019

Short-pulse High-energy Lasers and Ultrafast Optical Technologies

Showing 5 of 6 publications

Conference Committee Involvement (9)

High Power Lasers for Fusion Research VIII

25 January 2025 | San Francisco, United States

High-power, High-energy Lasers and Ultrafast Optical Technologies

24 April 2023 | Prague, Czech Republic

High Power Lasers for Fusion Research VII

1 February 2023 | San Francisco, California, United States

High Power Lasers and Applications

19 April 2021 | Online Only, Czech Republic

High Power Lasers for Fusion Research VI

6 March 2021 | Online Only, California, United States

Showing 5 of 9 Conference Committees

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