Low-wavenumber compensation with Zernike tilt for non-Kolmogorov turbulence phase screens
Abstract
The fast-Fourier-transform-based filtering method for phase screen generation remains popular for numerical simulation of optical propagation through turbulence; however, these screens inherently underrepresent the spectral density at low wavenumbers. Here, the “Z-tilt” approach is explored to augment the spectral density at low wavenumbers by adding a random phase tilt, which is derived from the wavefront phase statistics of a Zernike polynomial basis. This approach is computationally efficient and can be applied to any statistically homogeneous and isotropic refractive index field. An analytic result is provided for the von Kármán spectrum with finite outer scale. In a quantitative comparison with phase screens compensated for using a common subharmonic approach, the Z-tilt method shows the best agreement with the analytical structure function when the outer scale is greater than about three times the screen dimension. For outer scales of the order of the screen dimension, the subharmonic and a modified Z-tilt method give the most accurate results. A propagation simulation demonstrates that the aperture-averaged angle-of-arrival variance is accurately predicted using the Z-tilt method.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 06, 2023
- Source ID
- 10.1364/ao.475825
Entities
People
- Andreas Muschinski
- David Voelz
- Erandi Wijerathna
- Hanyu Zhan
Organizations
- Air Force Office of Scientific Research
- New Mexico State University
- Northwest Research Associates
- University of Colorado Boulder