Dr. Alexander Horn Profile

Dr. Alexander Horn

at Laser Zentrum Hannover e.V.

SPIE Involvement:

Author

Publications (17)

Proceedings Article | 16 February 2018 Presentation + Paper

Solving the logarithmic Monge-Ampère equation with a RK4-algorithm for beam shaping purposes of femtosecond laser beams with spatial light modulators

Alexander Kratsch, Markus Olbrich, Steffen Weißmantel, Alexander Horn

Proceedings Volume 10518, 105181L (2018) https://doi.org/10.1117/12.2287454

KEYWORDS: Beam shaping, Diffraction, Spatial light modulators, Convolution, Near field, Freeform optics, Computer generated holography, Algorithms, Laser processing

Read Abstract +

Proceedings Article | 25 February 2012 Paper

High-throughput process parallelization for laser surface modification on Si-solar cells: determination of the process window

Viktor Schütz, Alexander Horn, Uwe Stute

Proceedings Volume 8244, 82440X (2012) https://doi.org/10.1117/12.907972

KEYWORDS: Laser processing, Pulsed laser operation, Silicon, Semiconducting wafers, Diffractive optical elements, Semiconductor lasers, Solar cells, Reflectivity, Laser ablation, Gases

Read Abstract +

Proceedings Article | 2 March 2010 Paper

Temporal femtosecond pulse tailoring for nanoscale laser processing of wide-bandgap materials

Matthias Wollenhaupt, Lars Englert, Alexander Horn, Thomas Baumert

Proceedings Volume 7600, 76000X (2010) https://doi.org/10.1117/12.840511

KEYWORDS: Modulation, Atomic force microscopy, Femtosecond phenomena, Laser processing, Pulsed laser operation, Laser ablation, Silica, Scanning electron microscopy, Photomicroscopy, Materials processing

Read Abstract +

Proceedings Article | 12 May 2008 Paper

Investigations of the ultrafast laser induced melt dynamics by means of transient quantitative phase microscopy (TQPm)

Ilya Mingareev, Alexander Horn

Proceedings Volume 7005, 70050P (2008) https://doi.org/10.1117/12.782618

KEYWORDS: Microscopy, Glasses, Refractive index, Aluminum, Laser ablation, Microscopes, Femtosecond phenomena, Ultrafast lasers, Pulsed laser operation, Laser welding

Read Abstract +

Proceedings Article | 23 February 2008 Paper

Joining of thin glass with semiconductors by ultra-fast high-repetition laser welding

Alexander Horn, Ilja Mingaeev, Alexander Werth, Martin Kachel

Proceedings Volume 6880, 68800A (2008) https://doi.org/10.1117/12.762337

KEYWORDS: Glasses, Silicon, Microscopy, Ultrafast phenomena, Interfaces, Laser welding, Refractive index, Etching, Semiconductors, Humidity

Read Abstract +

Lighting applications like OLED or on silicon for electro-optical applications need a reproducible sealing process. The joining has to be strong, the permeability for gasses and humidity very low and the process itself has to be very localized not affecting any organic or electronic parts inside the sealed region. The actual sealing process using glue does not fulfil these industrial needs. A new joining process using ultra-fast laser radiation offers a very precise joining with geometry dimensions smaller than 50 μm. Ultra-fast laser radiation is absorbed by multi-photon absorption in the glass. Due to the very definite threshold for melting and ablation the process of localized heating can be controlled without cracking. Repeating the irradiation at times smaller than the heat diffusion time the temperature in the focus is increased by heat accumulation reaching melting of the glass. Mowing the substrate relatively to the laser beam generates a seal of re-solidified glass. Joining of glass is achieved by positioning the laser focus at the interface. A similar approach is used for glass-silicon joining. The investigations presented will demonstrate the joining geometry by microscopy of cross-sections achieved by welding two glass plates (Schott D263 and AF45) with focused IR femtosecond laser radiation (wavelength λ = 1045nm, repetition rate f = 1 MHz, pulse duration t_p = 500 fs, focus diameter w₀ = 4 μm, feeding velocity v= 1-10 mm/s). The strength of the welding seam is measured by tensile stress measurements and the gas and humidity is detected. A new diagnostic method for the on-line detection of the welding seam properties will be presented. Using a non-interferometric technique by quantitative phase microscopy the refractive index is measured during welding of glass in the time regime 0-2 μs. By calibration of the measured refractive index with a relation between refractive index and temperature a online-temperature detection can be achieved.

Proceedings Article | 7 June 2006 Paper

Observation of melt ejection in metals up to 1 µs after femtosecond laser irradiation by a novel pump-probe photography setup

I. Mingareev, A. Horn, E. Kreutz

Proceedings Volume 6261, 62610A (2006) https://doi.org/10.1117/12.669350

KEYWORDS: Laser ablation, Femtosecond phenomena, Metals, Pulsed laser operation, Mirrors, Aluminum, Copper, Plasma, Photography, Laser processing

Read Abstract +

Proceedings Article | 4 November 2005 Paper

Coloured marking inside glass by laser radiation

Grace Ligbado, Alexander Horn, Ernst Kreutz, Manfred Krauss, Norbert Siedow, Hartmut Hensel

Proceedings Volume 5989, 59890K (2005) https://doi.org/10.1117/12.631724

KEYWORDS: Glasses, Transmittance, Ultraviolet radiation, Absorption, Ions, Vanadium, Borosilicate glass, Laser marking, Oxides, Doping

Read Abstract +

Proceedings Article | 23 December 2004 Paper

Electron excitation in glasses and sapphire followed by time- and space-measuring tools

Ernst Kreutz, Alexander Horn, Reinhart Poprawe

Proceedings Volume 5620, (2004) https://doi.org/10.1117/12.580747

KEYWORDS: Glasses, Picosecond phenomena, Sapphire, Silica, Absorption, Quartz, Pulsed laser operation, Femtosecond phenomena, Laser beam propagation, Absorption spectroscopy

Read Abstract +

Proceedings Article | 8 October 2004 Paper

Formation of subwavelength-laser-induced periodic surface structures by tightly focused femtosecond laser radiation

Ralph Wagner, Jens Gottmann, Alexander Horn, Ernst Kreutz

Proceedings Volume 5662, (2004) https://doi.org/10.1117/12.596313

KEYWORDS: Silica, Femtosecond phenomena, Silicon, Polarization, Scanning electron microscopy, Refractive index, Semiconductor lasers, Thin films, Pulsed laser operation, Atomic force microscopy

Read Abstract +

Proceedings Article | 18 November 2003 Paper

Theoretical analysis of second harmonic characteristics generated by KTiOPO4 crystal

Kazufumi Nomura, Etsuji Ohmura, Alexander Horn, Isamu Miyamoto

Proceedings Volume 5063, (2003) https://doi.org/10.1117/12.540755

KEYWORDS: Crystals, Temperature metrology, Refractive index, Laser crystals, Nonlinear crystals, Second-harmonic generation, Absorption, Ferroelectric materials, Frequency conversion, Phase matching

Read Abstract +

Proceedings Article | 1 August 2003 Paper

Ultrafast pump & probe investigations on the interaction of femtosecond laser pulses with glass

Alexander Horn, Hooman Khajehnouri, Ernst-Wolfgang Kreutz, Reinhart Poprawe

Proceedings Volume 4948, (2003) https://doi.org/10.1117/12.516935

KEYWORDS: Glasses, Picosecond phenomena, Absorption, Femtosecond phenomena, Silica, Refractive index, Plasma, Quartz, Pulsed laser operation, Absorption spectroscopy

Read Abstract +

Proceedings Article | 18 June 2002 Paper

UV laser radiation-induced modifications and microstructuring of glass

Marc Talkenberg, Ernst-Wolfgang Kreutz, Alexander Horn, Michael Jacquorie, Reinhart Poprawe

Proceedings Volume 4637, (2002) https://doi.org/10.1117/12.470630

KEYWORDS: Glasses, Absorption, Cerium, Excimer lasers, Laser damage threshold, Pulsed laser operation, Silver, Ultraviolet radiation, Crystals, Laser processing

Read Abstract +

Proceedings Article | 30 April 2001 Paper

Nd:YAG laser micromachining of SiC precision structures for MEMS

Ernst-Wolfgang Kreutz, Ruth Weichenhain, Alexander Horn

Proceedings Volume 4407, (2001) https://doi.org/10.1117/12.425290

KEYWORDS: Silicon carbide, Laser processing, Pulsed laser operation, Micromachining, Microelectromechanical systems, Nd:YAG lasers, Semiconductor lasers, Waveguides, Polymers, Laser damage threshold

Read Abstract +

Proceedings Article | 25 January 2001 Paper

Dynamics of laser-induced cracking in glasses at a picosecond time scale

Alexander Horn, Ruth Weichenhain, Ernst-Wolfgang Kreutz, Reinhart Poprawe

Proceedings Volume 4184, (2001) https://doi.org/10.1117/12.413995

KEYWORDS: Picosecond phenomena, Plasma, Glasses, Pulsed laser operation, Refractive index, Laser beam diagnostics, High speed photography, Microscopy, Spatial resolution, Time resolved spectroscopy

Read Abstract +

Proceedings Article | 16 August 2000 Paper

Microholes in zirconia-coated Ni-superalloys for transpiration cooling of turbine blades

Alexander Horn, Ruth Weichenhain, S. Albrecht, Ernst-Wolfgang Kreutz, Jan Michel, Markus Niessen, Vadim Kostrykin, Wolfgang Schulz, A. Etzkorn, K. Bobzin, E. Lugscheider, Reinhart Poprawe

Proceedings Volume 4065, (2000) https://doi.org/10.1117/12.407331

KEYWORDS: Argon, Laser drilling, Oxygen, Pulsed laser operation, Coating, Zirconium dioxide, Gases, Multilayers, Laser systems engineering, Nitrogen

Read Abstract +

Proceedings Article | 3 June 1998 Paper

Processing ceramics by laser radiation

Ernst-Wolfgang Kreutz, Juergen Jandeleit, Ruth Weichenhain, Manfred Sommer, Alexander Horn, A. Curdt

Proceedings Volume 3274, (1998) https://doi.org/10.1117/12.309492

KEYWORDS: Ceramics, Laser processing, Silicon carbide, Thin films, Laser damage threshold, Excimer lasers, Particles, Picosecond phenomena, Pulsed laser operation, Nd:YAG lasers

Read Abstract +

Proceedings Article | 5 September 1997 Paper

Micromachining of metals and ceramics by nano- and picosecond laser radiation

Juergen Jandeleit, Alexander Horn, Ernst-Wolfgang Kreutz, Reinhart Poprawe

Proceedings Volume 3223, (1997) https://doi.org/10.1117/12.284498

KEYWORDS: Picosecond phenomena, Micromachining, Metals, Ceramics, Silicon, Precision optics, Control systems, Pulsed laser operation, Surface finishing

Read Abstract +

Showing 5 of 17 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years