Dr. Praveen K. Velpula Profile

Dr. Praveen K. Velpula

at UGC-DAE Consortium for Scientific Research

SPIE Involvement:

Author

Area of Expertise:

Sub-picosecond Laser Induced Damage Threshold , Ultrafast Imaging and Ultrafast Processes , Ultrafast beam Engineering , Ultrafast laser-Material Processing , Ultrafast Dynamics

Websites:

Company Website

My research in past several years has focused mainly on laser-material processing, laser damage, ultrafast beam engineering, and ultrafast dynamics.

My key achievements in the field:
1) Localization of the light well below the diffraction limit (sub-micron scales) in dielectrics.
2) Ultrafast laser induced 3-D nano structuring in bulk dielectrics.
3) Ultrafast imaging of nano structuring and free carrier dynamics on the formation of positive and negative index structures formation.
4) Study of laser-induced damage threshold (LIDT) of various optical components for ELI's petawatt class lasers.
5) Development of two color/single color pump-probe microscopy.
6) Development of high vacuum LIDT test station.
7) Optical and structural surface cleanliness and verification.

Proceedings Article | 8 June 2023 Presentation

Sub-TW laser pulses via post-compression of 9 mJ, 1.2 picosecond laser pulses to 13 fs (Conference Presentation)

Nikita Khodakovskiy, Supriya Rajhans, Esmerando Escoto, Praveen Velpula, Bonaventura Farace, Rob Shalloo, Kristjan Poder, Jens Osterhoff, Wim Leemans, Ingmar Hartl, Christoph Heyl

Proceedings Volume PC12577, PC125770F (2023) https://doi.org/10.1117/12.2669587

KEYWORDS: Ultrafast phenomena, Picosecond phenomena, Pulse signals, Nonlinear transmission, Neon, Mirrors, Medicine, Materials science, Laser systems engineering, Laser applications

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Proceedings Article | 2 December 2022 Presentation + Paper

Comparison of high power sputtered dielectric mirrors for PW laser

T. Willemsen, T. Groß, M. Gauch, H. Ehlers, D. Kramer, P. Velpula, Wolfgang Ebert

Proceedings Volume 12300, 123000H (2022) https://doi.org/10.1117/12.2642134

KEYWORDS: Mirrors, Laser induced damage, Manufacturing, Optical coatings, Optics manufacturing, Dielectrics, Sputter deposition, Dielectric mirrors, Femtosecond lasers

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SPIE Journal Paper | 19 May 2020

Femtosecond laser damage resistance of beam dump materials for high-peak power laser systems

Praveen Velpula, Daniel Kramer, Michal Ďurák, Bedřich Rus

OE, Vol. 59, Issue 05, 056108, (May 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.5.056108

KEYWORDS: Glasses, Laser damage threshold, Resistance, Femtosecond phenomena, Laser systems engineering, Laser induced damage, Polarization, Reflectivity, Chemical vapor deposition, Thin film coatings

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Proceedings Article | 26 April 2019 Presentation + Paper

The beam dump materials and their LIDT measurements for PW/multi-PW laser systems

Praveen Velpula, Daniel Kramer, Michal Ďurák, Bedřich Rus

Proceedings Volume 11034, 110340P (2019) https://doi.org/10.1117/12.2523070

KEYWORDS: Glasses, Laser damage threshold, Absorbance, Thin film coatings, Laser systems engineering, Reflectivity, High power lasers, Laser induced damage

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Proceedings Article | 26 June 2017 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 | 6 December 2016 Paper

Comparison of different LIDT testing protocols for PW and multi-PW class high-reflectivity coatings

Michal Ďurák, Daniel Kramer, Praveen Velpula, Alexander Meadows, Josef Cupal, Bedrĭch Rus

Proceedings Volume 10014, 100140O (2016) https://doi.org/10.1117/12.2245182

KEYWORDS: Cameras, Laser induced damage, Laser damage threshold, Resistance, Optical components, Raster graphics, Damage detection, Contamination, Mirrors, Polarization

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SPIE Journal Paper | 4 November 2016

Laser-induced damage threshold tests of ultrafast multilayer dielectric coatings in various environmental conditions relevant for operation of ELI beamlines laser systems

Michal Ďurák, Praveen Velpula, Daniel Kramer, Josef Cupal, Tomáš Medřík, Jan Hřebíček, Jiří Golasowski, Davorin Peceli, Michaela Kozlová, Bedřich Rus

OE, Vol. 56, Issue 01, 011024, (November 2016) https://doi.org/10.1117/12.10.1117/1.OE.56.1.011024

KEYWORDS: Resistance, Laser damage threshold, Laser induced damage, Ultrafast phenomena, Laser systems engineering, Dielectrics, Multilayers, Optical coatings, Bioalcohols, Mirrors

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Proceedings Article | 23 November 2015 Paper

Ultrafast beam dump materials and mirror coatings tested with the ELI beamlines LIDT test station

Michal Ďurák, Daniel Kramer, Praveen Velpula, Josef Cupal, Tomáš Medřík, Jan Hřebíček, Jiří Golasowski, Davorin Peceli, Ladislav Fekete, Václav Štepán, Michaela Kozlová, Bedřich Rus

Proceedings Volume 9632, 96321B (2015) https://doi.org/10.1117/12.2194970

KEYWORDS: Atomic force microscopy, Ultrafast phenomena, Mirrors, Laser damage threshold, Optical coatings, Femtosecond phenomena, Ultrafast lasers, Optical components, Gases, Fractal analysis, Reflectivity, Microscopes, Light scattering, Bioalcohols, Contamination

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SPIE Journal Paper | 24 July 2014

Role of free carriers excited by ultrafast Bessel beams for submicron structuring applications

Praveen Kumar Velpula, Manoj Kumar Bhuyan, Cyril Mauclair, Jean-Philippe Colombier, Razvan Stoian

OE, Vol. 53, Issue 07, 076108, (July 2014) https://doi.org/10.1117/12.10.1117/1.OE.53.7.076108

KEYWORDS: Bessel beams, Pulsed laser operation, Laser energy, Picosecond phenomena, Silica, Femtosecond phenomena, Ultrafast phenomena, Refractive index, Ultrafast imaging, Laser beam propagation

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Proceedings Article | 6 March 2014 Paper

Ultrafast imaging of free carriers: controlled excitation with chirped ultrafast laser Bessel beams

P. K. Velpula, M. K. Bhuyan, C. Mauclair, J. P. Colombier, R. Stoian

Proceedings Volume 8967, 896711 (2014) https://doi.org/10.1117/12.2039119

KEYWORDS: Pulsed laser operation, Bessel beams, Laser energy, Picosecond phenomena, Silica, Femtosecond phenomena, Refractive index, Ultrafast imaging, Ionization, Laser beam propagation

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