Mr. Jeffrey G. Thomas Profile

Jeffrey G. Thomas

Division Head at Pennsylvania State Univ

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Publications (11)

Proceedings Article | 2 December 2022 Presentation + Paper

1077-nm, CW mirror thin film damage competition

Raluca Negres, Christopher Stolz, Sage DeFrances, David Bernot, Joseph Randi, Jeffrey Thomas

Proceedings Volume 12300, 1230002 (2022) https://doi.org/10.1117/12.2641371

KEYWORDS: Continuous wave operation, Absorption, Laser induced damage, Deposition processes, Laser irradiation, Thin films

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Proceedings Article | 23 November 2017 Paper

CW laser damage testing of RAR nano-textured fused silica and YAG

Bruce MacLeod, Douglas Hobbs, Anthony Manni, Ernest Sabatino, David Bernot, Sage DeFrances, Joseph Randi, Jeffrey Thomas

Proceedings Volume 10447, 1044705 (2017) https://doi.org/10.1117/12.2280498

KEYWORDS: Absorption, Thin films, YAG lasers, Continuous wave operation, Thin film coatings, Silica, Laser induced damage, Antireflective coatings, Laser damage threshold, Nanophotonics, Photonic microstructures

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A study of the continuous wave (CW) laser induced damage threshold (LiDT) of fused silica and yttrium aluminum garnet (YAG) optics was conducted to further illustrate the enhanced survivability within high power laser systems of an anti-reflection (AR) treatment consisting of randomly distributed surface relief nanostructures (RAR). A series of three CW LiDT tests using the 1070nm wavelength, 16 KW fiber laser test bed at Penn State Electro-Optic Center (PSEOC) were designed and completed, with improvements in the testing protocol, areal coverage, and maximum exposure intensities implemented between test cycles. Initial results for accumulated power, stationary site exposures of RAR nano-textured optics showed no damage and low surface temperatures similar to the control optics with no AR treatment. In contrast, optics with thin-film AR coatings showed high surface temperatures consistent with absorption by the film layers. Surface discriminating absorption measurements made using the Photothermal Common-path Interferometry (PCI) method, showed zero added surface absorption for the RAR nanotextured optics, and absorption levels in the 2-5 part per million range for thin-film AR coated optics. In addition, the surface absorption of thin-film AR coatings was also found to have localized absorption spikes that are likely pre-cursors for damage. Subsequent CW LiDT testing protocol included raster scanning an increased intensity focused beam over the test optic surface where it was found that thin-film AR coated optics damaged at intensities in the 2 to 5 MW/cm² range with surface temperatures over 250C during the long-duration exposures. Significantly, none of the 10 RAR nano-textured fused silica optics tested could be damaged up to the maximum system intensity of 15.5 MW/cm², and surface temperatures remained low. YAG optics tested during the final cycle exhibited a similar result with RAR nano-textured surfaces surviving intensities over 3 times higher than thin-film AR coated surfaces. This result was correlated with PCI measurements that also show zero-added surface absorption for the RAR nano-textured YAG optics.

Proceedings Article | 24 February 2009 Paper

A study of material removal rates for shallow drilling with an ultrashort pulse laser

B. Campbell, L. Forster, J. Moore, T. Lehecka, J. Thomas, V. Semak

Proceedings Volume 7201, 72010I (2009) https://doi.org/10.1117/12.810173

KEYWORDS: Laser drilling, Pulsed laser operation, Aluminum, Titanium, Picosecond phenomena, Copper, Plasma, Ultrafast phenomena, Interferometers, Laser ablation

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Proceedings Article | 20 February 2008 Paper

Shallow hole drilling with ultrashort pulse lasers

B. Campbell, L. Forster, T. Lehecka, J. Thomas, V. Semak

Proceedings Volume 6879, 68790J (2008) https://doi.org/10.1117/12.760630

KEYWORDS: Aluminum, Laser ablation, Pulsed laser operation, Picosecond phenomena, Laser drilling, Ultrafast phenomena, Copper, Reflectivity, Laser energy, Absorption

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Proceedings Article | 3 June 2007 Open Access

Supercontinuum generation in photonic crystal fibers for undergraduate laboratory

Gregory Helmininack, Derek Gladysiewski, Feng Zhou, Ken Hershman, Ben Campbell, Jeff Thomas

Proceedings Volume 9665, 96651Y (2007) https://doi.org/10.1117/12.2207809

KEYWORDS: Photonic crystal fibers, Supercontinuum generation, Nanotechnology, Physics, Fiber lasers, Visible radiation, Picosecond phenomena, Cladding, Dispersion, Pulsed laser operation

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Proceedings Article | 7 June 2006 Paper

An analysis of ultrashort pulse laser micromachining parameters for the optimization of shallow hole drilling

Benjamin Campbell, Vladimir Semak, Jeffrey Thomas

Proceedings Volume 6261, 62612D (2006) https://doi.org/10.1117/12.669402

KEYWORDS: Laser drilling, Composites, Pulsed laser operation, Mercury cadmium telluride, Polarization, Femtosecond phenomena, Laser ablation, Micromachining, Ultrafast phenomena, Laser systems engineering

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Proceedings Article | 23 February 2006 Paper

Multiple applications for the 10kW fiber laser at the Electro-Optics Center

D. Jason Sames, Thomas Lehecka, Jeffrey Thomas

Proceedings Volume 6101, 61011S (2006) https://doi.org/10.1117/12.649786

KEYWORDS: Fiber lasers, Composites, Weapons, Optical testing, Coating, Microwave radiation, Laser systems engineering, Optical coatings, Electro optics, Laser applications

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Proceedings Article | 12 April 2005 Paper

Comparison of drilling rates and material removal dynamics for nanosecond and femtosecond laser pulses

Vladimir Semak, Jeffrey Thomas, Benjamin Campbell

Proceedings Volume 5713, (2005) https://doi.org/10.1117/12.592149

KEYWORDS: Laser drilling, Femtosecond phenomena, Pulsed laser operation, Laser systems engineering, Laser energy, Copper, Reflectivity, Aluminum, Photodiodes, Diode pumped solid state lasers

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Proceedings Article | 15 July 2004 Paper

Melting threshold and melt removal dynamics during laser interaction with steel and HgCdTe in femtosecond regime

Vladimir Semak, Jeffrey Thomas, Benjamin Campbell

Proceedings Volume 5339, (2004) https://doi.org/10.1117/12.527725

KEYWORDS: Pulsed laser operation, Femtosecond phenomena, Laser drilling, Laser energy, Mercury cadmium telluride, Laser damage threshold, Optical testing, Nickel, Absorption, Fiber lasers

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Proceedings Article | 3 December 2003 Paper

Laser beam shaping by holographic optical elements

Nickolai Kukhtarev, Tatiana Kukhtareva, Leonid Glebov, Vadim Smirnov, J. Schrimpf, Jeffrey Thomas

Proceedings Volume 5257, (2003) https://doi.org/10.1117/12.545847

KEYWORDS: Beam shaping, Holographic optical elements, Glasses, Energy transfer, Crystals, Diffraction gratings, Holography, Diffraction, Pulsed laser operation, Laser applications

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Proceedings Article | 17 October 2003 Paper

Ultrashort-pulse laser micromachining testbed development

Jeff Thomas, J. Schriempf, Randy Gilmore

Proceedings Volume 4977, (2003) https://doi.org/10.1117/12.479225

KEYWORDS: Femtosecond phenomena, Pulsed laser operation, Micromachining, Laser drilling, Ultrafast phenomena, Mercury cadmium telluride, Laser development, Semiconductor lasers, Head, Laser ablation

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Showing 5 of 11 publications

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