Multiwavelength Laser Propagation Study -- 3
Abstract
An extensive experimental investigation of multiwavelength laser beam scintillations and atmospheric turbulence characteristics has been completed. It has been found that turbulence spectra approximate the inertial-subrange model only under conditions of strong turbulence, which corresponds with saturation of scintillations at visible and near-IR wavelengths. Hence, it is only at longer wavelengths (such as 10.6 microns) that Rytov analyses utilizing the inertial subrange have substantial value. The saturation phenomenon occurs at the same scintillation levels independent of wavelength, and significant falloff of scintillation 'beyond saturation' is observed. Covariance measurements show transverse amplitude correlation lengths which are significantly affected by strong turbulence; the correlation lengths increase at shorter wavelengths while decreasing at longer wavelengths, as turbulence increases. Receiver aperture-averaging results at visible wavelengths show that the large-aperture smoothing of total-signal fluctuations is much less effective than theoretically predicted, and confirm the especially-poor averaging in strong turbulence conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1971
- Accession Number
- AD0717088
Entities
People
- J. R. Kerr
Organizations
- Oregon Health & Science University