Propagation through and characterization of atmospheric and oceanic phenomena: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.

This joint feature issue in Applied Optics and JOSA A collects articles focused on the topic of propagation through and characterization of atmospheric oceanic phenomena. The papers cover a broad range of topics, many of which were addressed at the 2023 Propagation Through and Characterization of Atmospheric Oceanic Phenomena (pcAOP) Topical Meeting at the Optica Imaging Congress in Boston, Massachusetts, 14-17 August 2023. These papers are supplemented by numerous examples of the current state of research in the field.

Comparative analysis of 2 estimation methods for sonic anemometer data.

Wind speed and sonic temperature measured with ultrasonic anemometers are often utilized to estimate the refractive index structure parameter 2, a vital parameter for optical propagation. In this work, we compare four methods to estimate 2 from 2, using the same temporal sonic temperature data streams for two separated sonic anemometers on a homogenous path. Values of 2 obtained with these four methods using field trial data are compared to those from a commercial scintillometer and from the differential image motion method using a grid of light sources positioned at the end of a common path.

Propagation through and characterization of atmospheric and oceanic phenomena: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.

This joint feature issue in Applied Optics and JOSA A collects articles focused on the topic of propagation through and characterization of atmospheric oceanic phenomena. The papers cover a broad range of topics, many of which were addressed at the 2023 Propagation Through and Characterization of Atmospheric Oceanic Phenomena (pcAOP) Topical Meeting at the Optica Imaging Congress in Boston, Massachusetts, 14-17 August 2023. These papers are supplemented by numerous examples of the current state of research in the field.

Active-tracking scaling laws using the noise-equivalent angle due to speckle.

It is well known to system engineers that speckle imposes a limitation on active-tracking performance, but scaling laws that quantify this limitation do not currently exist in the peer-reviewed literature. Additionally, existing models lack validation through either simulation or experimentation. With these points in mind, this paper formulates closed-form expressions that accurately predict the noise-equivalent angle due to speckle.

Comparison of probability density functions for aperture-averaged irradiance fluctuations of a Gaussian beam with beam wander.

Over the years, there has been much interest in the use of optical wavelengths for communication because of the potential for high data rates. However, the performance of these systems can become significantly degraded due to turbulence-induced signal fluctuations. These fluctuations can be minimized by enlarging the receiving aperture, thereby averaging the fluctuations.

Calculating structure function constant from measured C in non-Kolmogorov and anisotropic turbulence including inner scale effects.

Optical scintillometers used to characterize turbulence are based on assumptions of isotropic, Kolmogorov turbulence following a κ spectral power law. However, experimental data suggest that the turbulence may at times be anisotropic and non-Kolmogorov. In this work, consideration is given to converting from the structure function constant, Cn2, based on isotropic, Kolmogorov statistics to its generalized anisotropic, non-Kolmogorov form, C˜n2, for point receiver and large-aperture receiver scintillometers.

Evolution of near-ground optical turbulence over concrete runway throughout multiple days in summer and winter.

Experimental data are presented that demonstrate the evolution of the anisotropy/isotropy of atmospheric statistics throughout the course of four days (two winter, two summer) near the ground over a concrete runway in Florida. In late January and early February of 2017, a 532 nm near-plane-wave beam was propagated 1 and 2 km at a height of 2 m above the runway, and irradiance fluctuations were captured on a CCD array. In August of 2017, a 532 nm Gaussian beam was propagated 100 m at a height of near 2 m, and fluctuation data were captured on a CCD array.

Near ground measure and theoretical model of plane wave covariance of intensity in anisotropic turbulence.

Experimental measurements were recently made which displayed characteristics of plane wave propagation through anisotropic optical turbulence. A near-plane wave beam was propagated a distance of 1 and 2 km at a height of 2 m above the concrete runway at the Shuttle Landing Facility, Kennedy Space Center, Florida, during January and February of 2017. The spatial-temporal fluctuations of the beam were recorded, and the covariance of intensity was calculated.