Wave-optics simulation of dynamic speckle: II. In an image plane.

This two-part paper demonstrates the use of wave-optics simulations to model the effects of dynamic speckle. In Part II, we formulate closed-form expressions for the analytical irradiance correlation coefficient, specifically in the image plane of an optical system. These expressions are for square, circular, and Gaussian limiting apertures and four different modes of extended-object motion, including in-plane and out-of-plane translation and rotation.

Wave-optics simulation of dynamic speckle: I. In a pupil plane.

This two-part paper demonstrates the use of wave-optics simulations to model the effects of dynamic speckle. In Part I, we formulate closed-form expressions for the analytical irradiance correlation coefficient, specifically in the pupil plane of an optical system. These expressions are for square, circular, and Gaussian scattering spots and four different modes of extended-object motion, including in-plane and out-of-plane translation and rotation.

Improved adaptive-optics performance using polychromatic speckle mitigation.

Adaptive-optics (AO) systems correct the optical distortions of atmospheric turbulence to improve resolution over long paths. In applications such as remote sensing, object tracking, and directed energy, the AO system's beacon is often an extended beacon reflecting off an optically rough surface. This situation produces speckle noise that can corrupt the wavefront measurements of the AO system, degrading its correction of the turbulence.

Speckle mitigation for wavefront sensing in the presence of weak turbulence.

When measuring atmospheric turbulence along the propagation path to an extended non-cooperative target, a wavefront sensor normally suffers from severe noise due to speckle. In this work, we quantify the benefits of speckle mitigation via polychromatic illumination for a Shack-Hartmann wavefront sensor. We obtain results over a wide range of conditions by using the spectral-slicing approach to polychromatic wave-optics simulations.

Polychromatic wave-optics models for image-plane speckle. 2. Unresolved objects.

Polychromatic laser light can reduce speckle noise in many wavefront-sensing and imaging applications. To help quantify the achievable reduction in speckle noise, this study investigates the accuracy of three polychromatic wave-optics models under the specific conditions of an unresolved object. Because existing theory assumes a well-resolved object, laboratory experiments are used to evaluate model accuracy.

Polychromatic wave-optics models for image-plane speckle. 1. Well-resolved objects.

Polychromatic laser light can reduce speckle noise in wavefront-sensing and imaging applications that use direct-detection schemes. To help quantify the achievable reduction in speckle, this paper investigates the accuracy and numerical efficiency of three separate wave-optics methods. Each method simulates the active illumination of extended objects with polychromatic laser light.

Enhanced, fast-running scaling law model of thermal blooming and turbulence effects on high energy laser propagation.

A new scaling law model is presented to rapidly simulate thermal blooming and turbulence effects on high energy laser propagation, producing results approaching the quality normally only available using wave-optics code, but at much faster speed. The model convolves irradiance patterns originating from two distinct scaling law models, one with a proficiency in thermal blooming effects and the other in turbulence. To underscore the power of the new model, results are verified for typical, realistic scenarios by direct comparison with wave optics simulation.