Dr. Cord L. Arnold Profile

Dr. Cord L. Arnold

Assistant Professor at Lund Univ

SPIE Involvement:

Author

Proceedings Article | 7 March 2014 Open Access

Compact, high-repetition-rate OPCPA system for high harmonic generation

Jan Matyschok, Thomas Binhammer, Tino Lang, Oliver Prochnow, Stefan Rausch, Piotr Rudawski, Anne Harth, Miguel Miranda, Chen Guo, Eleonora Lorek, Johan Mauritsson, Cord Arnold, Anne L'Huillier, Uwe Morgner

Proceedings Volume 8972, 89720L (2014) https://doi.org/10.1117/12.2035810

KEYWORDS: Oscillators, Optical amplifiers, High harmonic generation, Mirrors, Extreme ultraviolet, Crystals, Fiber amplifiers, Second-harmonic generation, Signal detection, Phase matching

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Proceedings Article | 23 August 2011 Paper

Focusing of ultrashort sub-TW laser pulses in air: supercontinuum emission

Prem Kiran P., S. Bagchi, C. Arnold, S. Rama Krishnan, G. Ravindra Kumar, A. Couairon

Proceedings Volume 8173, 81730Q (2011) https://doi.org/10.1117/12.898485

KEYWORDS: Plasma, Femtosecond phenomena, Pulsed laser operation, Wave propagation, Atmospheric propagation, Laser applications, Ultrafast phenomena, Laser energy, Charge-coupled devices, Ionization

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SPIE Journal Paper | 1 November 2010 Open Access

Interaction dynamics of spatially separated cavitation bubbles in water

Nadine Tinne, Silvia Schumacher, Valeria Nuzzo, Cord Arnold, Holger Lubatschowski, Tammo Ripken

JBO, Vol. 15, Issue 06, 068003, (November 2010) https://doi.org/10.1117/12.10.1117/1.3526366

KEYWORDS: Cavitation, Pulsed laser operation, Laser tissue interaction, Laser energy, Laser cutting, Laser optics, Fusion energy, Laser vision correction, Objectives, Femtosecond phenomena

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Proceedings Article | 5 June 2010 Paper

Supercontinuum emission from tightly focused femtosecond pulses in air: beyond intensity clamping

P. Prem Kiran, Suman Bagchi, Siva Rama Krishnan, C. Arnold, G. Ravindra Kumar, A. Couairon

Proceedings Volume 7728, 77281P (2010) https://doi.org/10.1117/12.854218

KEYWORDS: Plasma, Femtosecond phenomena, Atmospheric propagation, Polarization, Laser energy, Laser beam propagation, Absorption, Ionization, Ultrafast phenomena, Spectroscopy

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Proceedings Article | 15 February 2008 Paper

Numerical modeling of nonlinear plasma formation in high-NA micromachining of transparent materials and biological cells using ultrashort laser pulses

C. Arnold, A. Heisterkamp, W. Ertmer, H. Lubatschowski

Proceedings Volume 6881, 688104 (2008) https://doi.org/10.1117/12.761206

KEYWORDS: Plasma, Ultrafast phenomena, Plasma generation, Ionization, Electrons, Nonlinear optics, Absorption, Surgery, Soft tissue optics, Tissue optics

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Ultrashort laser pulses recently found extensive application in micro- and nanostructuring, in refractive surgery of the eye, and in biophotonics. Due to the high laser intensity required to induce optical breakdown, nonlinear plasma formation is generally accompanied by a number of undesired nonlinear side-effects such as self-focusing, filamentation and plasma-defocusing, seriously limiting achievable precision and reproducibility. To reduce pulse energy, enhance precision, and limit nonlinear side effects, applications of ultrashort pulses have recently evolved towards tight focusing using high numerical aperture microscope objectives. However, from the theoretical and numerical point of view generation of optical breakdown at high numerical aperture focusing was barely studied. To simulate the interaction of ultrashort laser pulses with transparent materials, a comprehensive numerical model taking into account nonlinear propagation, plasma generation as well as the pulse's interaction with the generated plasma is introduced. By omitting the widely used scalar and paraxial approximations a novel nonlinear propagation equation is derived, especially suited to meet the conditions of high numerical aperture focusing. The multiple rate equation (MRE) model is used to simultaneously calculate the generation of free electrons. Nonparaxial and vectorial diffraction theory provides initial conditions. The theoretical model derived is applied to numerically study the generation of optical breakdown plasmas, concentrating on parameters usually found in experimental applications of cell surgery. Water is used as a model substance for biological soft tissue and cellular constituents. For focusing conditions of numerical aperture NA < 0.9 generation of optical breakdown is shown to be strongly influenced by plasma defocusing, resulting in spatially distorted breakdown plasmas of expanded size. For focusing conditions of numerical aperture NA ≥ 0.9 on the other hand generation of optical breakdown is found to be almost unaffected by distortive side-effects, perfectly suited for material manipulation of highest precision.

Proceedings Article | 13 March 2007 Paper

Modeling of ultrashort pulse propagation and nonlinear plasma formation in transparent Kerr media using realistic initial conditions

C. Arnold, W. Ertmer, H. Lubatschowski

Proceedings Volume 6460, 646010 (2007) https://doi.org/10.1117/12.698934

KEYWORDS: Plasma, Electrons, Ionization, Ultrafast phenomena, Plasma generation, Wave propagation, Diffraction, Refractive index, Polarization, Objectives

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Ultrashort laser pulses tightly focused provide intensity sufficient to initialize nonlinear ionization processes. Thus a plasma is generated in the focal region eventually resulting in optical breakdown. The deterministic character of this nonlinear interaction enables the generation of precise and highly reproducible material alteration. To gain better spatial precision applications have recently evolved strongly towards tight focusing of ultrashort pulses using microscope objectives as focusing units. The pulse energy required to generate optical breakdown was thus reduced to nanojoules or even below. The mechanical effects subsequent to plasma generation can be minimized to the very focus. Cell surgery with ultrashort pulses enables to precisely ablate cell organelles without observable hazardous effects to the surroundings or the entire cell. To numerically investigate the nonlinear interaction of ultrashort pulses with transparent media, a model including both nonlinear pulse propagation and plasma generation is introduced. The numerical code is based on a (3+1)-dimensional nonlinear Schrödinger equation describing the pulse propagation and the interaction with the density of free electrons that are generated in the focus. The nonlinear wave equation was derived taking into account both nonparaxial and vectorial effects to accurately include tight focusing at high numerical aperture. A multi rate equation model for dielectrics recently published by B. Rethfeld is used to simultaneously calculate the generation of free electrons. Numerical calculations based on this model are used to understand the dependence between size, geometry and density of optical breakdown plasmas in various focusing geometries of high numerical aperture. The code enables to use arbitrary initial conditions for the laser field in the focus. At high numerical aperture it is most important to start the simulation using realistic initial conditions. Especially the vectorial character of the electric field is most important to be considered. Thus a vectorial diffraction integral was used to calculate initial conditions at high numerical aperture. The code is applicable to any transparent Kerr medium, whose linear and nonlinear optical parameters are known. Within this work the code was applied to water as a model substance to biological soft tissue and cellular constituents.

Proceedings Article | 28 February 2006 Paper

Simulation of ultrashort pulse induced plasma generation and interaction within the bulk of transparent Kerr media

C. Arnold, W. Ertmer, H. Lubatschowski

Proceedings Volume 6108, 610808 (2006) https://doi.org/10.1117/12.645637

KEYWORDS: Electrons, Plasma, Ionization, Ultrafast phenomena, Plasma generation, Gaussian beams, Tissue optics, Refractive index, Pulsed laser operation, Tissues

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