Propagation of a Focused Laser Beam in a Turbulent Atmosphere.

by R. F. Lutomirski

Purchase Print Copy

 FormatList Price Price
Add to Cart Paperback32 pages $20.00 $16.00 20% Web Discount

A method of calculating the performance of a laser system with beam truncated by focusing optics in a turbulent atmosphere. Previous analyses have been limited to vacuum calculations with untruncated beams, and even then have not conserved the irradiance. This approach separates the geometry of the problem (the complex aperture distribution) from the beam propagation. The turbulence parameters appear only in the mutual coherence function describing the reduction in lateral coherence with increasing distance. Based on proofs presented in RM-6055, this report shows that, while the vacuum focal point intensity for a given laser power output will increase with finer focusing, the effect of turbulence limits this increase. Turbulence can virtually eliminate the vacuum advantage of visible over infrared wave-lengths in focusing the beam at practical ranges. To predict beam patterns for design purposes, we need direct mutual coherence function measurements, now notably lacking. 32 pp. Ref. (MW)

This report is part of the RAND Corporation Report series. The report was a product of the RAND Corporation from 1948 to 1993 that represented the principal publication documenting and transmitting RAND's major research findings and final research.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.