16 August 2000 Very high coupling coefficients at low laser fluence with a structured target
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Proceedings Volume 4065, High-Power Laser Ablation III; (2000) https://doi.org/10.1117/12.407330
Event: High-Power Laser Ablation, 2000, Santa Fe, NM, United States
Results are presented of the first measurements of laser-ablation impulse on structured targets of the modified Fabbro type in which impulse coupling coefficients Cm up to 500 dyne-s/J were obtained for 85-ns duration laser pulses by direct measurement with momentum pendula. Our target design generated these Cm values for single-pulse laser fluence of 1.2 J/cm2 and peak intensity 14 MW/cm2, an order of magnitude below the intensity at which similar coupling has been observed before. This result is important for the ORION demonstration, since it effectively closes a factor- of-20 deficit between presently available projected intensity at 300 km range and the intensity required for optimum coupling to standard materials. The Nd:glass laser employed in these measurements had 1.05 micrometer wavelength and pulse duration from 25 to 100 ns. Ambient pressure was less than 10 millitorr. Impulse coupling data on water ice, stone, carbon phenolic, PMMA and other materials were also obtained, for cross-calibration and because of interest in applications to 'uncooperative' natural bodies in space. We discuss the significance of these results for planning a laser propulsion demonstration in space, as well as possible extensions which could yield appropriate Cm for repetitively- pulsed propulsion of objects into low Earth orbit (LEO).
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Claude R. Phipps, Claude R. Phipps, Daniel B. Seibert, Daniel B. Seibert, Robert W. Royse, Robert W. Royse, Gregory King, Gregory King, Jonathan W. Campbell, Jonathan W. Campbell, "Very high coupling coefficients at low laser fluence with a structured target", Proc. SPIE 4065, High-Power Laser Ablation III, (16 August 2000); doi: 10.1117/12.407330; https://doi.org/10.1117/12.407330

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