Systematic corrections to quadratic approximations for power-law structure functions: the δ expansion
- 1 March 1981
- journal article
- Published by Optica Publishing Group in Journal of the Optical Society of America
- Vol. 71 (3), 321-326
- https://doi.org/10.1364/josa.71.000321
Abstract
A new perturbation expansion for optical propagation in turbulence is presented. The method consists of expanding the power of the (Markov) refractive-index structure function about the trivial value 2. By providing a method of obtaining systematic corrections to results obtained by using a quadratic approximation to the structure function, the expansion permits quantitative estimation of the errors in these results. It is shown that this expansion necessarily introduces an arbitrary length, even in zeroth order (quadratic approximation). This length may be adjusted to improve the convergence of the expansion, thereby giving insight into the most-important-length scale of the problem. Essential differences are noted between optical processes in which the effects of overall wave-front tilts cancel and processes in which they do not. In the latter, the δ expansion gives (in low order) excellent approximations for all turbulence strengths, and the most important length decreases in increasing turbulence. In a tilt-canceling process, however, only moderate improvement over a weak-turbulence expansion is obtained, and the most important length appears to increase with the strength of the turbulence.Keywords
This publication has 8 references indexed in Scilit:
- Meaning of quadratic structure functionsJournal of the Optical Society of America, 1980
- Optical beam propagation for a partially coherent source in the turbulent atmosphereJournal of the Optical Society of America, 1979
- Spatial correlation of phase-expansion coefficients for propagation through atmospheric turbulenceJournal of the Optical Society of America, 1979
- Path integrals for waves in random mediaJournal of Mathematical Physics, 1979
- Atmospheric propagation of partially coherent radiation*Journal of the Optical Society of America, 1978
- Propagation of a Finite Optical Beam in an Inhomogeneous MediumApplied Optics, 1971
- Optical Resolution Through a Randomly Inhomogeneous Medium for Very Long and Very Short ExposuresJournal of the Optical Society of America, 1966
- Statistics of a Geometric Representation of Wavefront DistortionJournal of the Optical Society of America, 1965