MULTIWAVELENGTH LASER PROPAGATION STUDY--2
Quarterly progress rept. no. 2, 15 Sep-15 Dec 1969
OREGON GRADUATE CENTER FOR STUDY AND RESEARCH PORTLAND
Pagination or Media Count:
In conducting multiwavelength scintillation experiments over a one mile path, it was found that a finite-sized transmitter aperture does not represent a true spherical-wave source, regardless of the beam divergence used. This observation has important implications for the interpretation of other data on the saturation of scintillations, and in the present experiments has lead to the redesign of the transmitter to achieve a virtual point source. This has been completed, including a provision for independently increasing the aperture at each wavelength up to two inches in diameter, for later transmitter- aperture-dependence measurements. A highly-developed thermal probe system for the detailed study of turbulence structure was made completely operational, and a portable laser system was fabricated for independent optical turbulence strength measurements. All subsystems of the experimental facility are operating without problems, and no further modifications are contemplated. In order to put the problem of atmospheric scintillations in current perspective and to guide the comprehensive experiments, a discussion of recent experimental and theoretical issues is given.