Mr. David Bernot Profile

David Bernot

at Penn State Univ

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Author

Publications (4)

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 | 26 May 2011 Paper

High energy microlaser and compact MOPA transmitter

Brian Brickeen, Dave Bernot, Eliot Geathers, Joseph Mosovsky

Proceedings Volume 8039, 80391A (2011) https://doi.org/10.1117/12.883247

KEYWORDS: Oscillators, Optical amplifiers, Q switching, Crystals, Transmitters, Laser crystals, Diodes, Absorption, Nd:YAG lasers, Amplifiers

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Proceedings Article | 22 February 2011 Paper

Novel applications of sub-surface laser machining

B. Campbell, L. Forster, D. Bernot

Proceedings Volume 7920, 79200T (2011) https://doi.org/10.1117/12.876050

KEYWORDS: Glasses, Laser marking, Etching, Pulsed laser operation, Manufacturing, Laser applications, Laser cutting, Laser processing, Ions, Picosecond phenomena

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