Laser imaging through atmospheric turbulence is a challenging problem due primarily to turbulence near the aperture. Amplitude measurements of the return beam in the aperture plane are less sensitive to near-field turbulence, but contain limited information about the Fourier phase of the target image. We propose a method of using deconvolution of laser speckle degraded imagery, together with pupil plane techniques, to produce coherent image reconstructions with spatial resolution not limited by the atmospheric conditions. The technique is demonstrated using computer simulation.
Since it is known that the aperture of an imaging system limits spatial its resolution, it is desirable to form
larger apertures. By taking advantage of the coherence properties of laser light, it is possible to form an optical
synthetic aperture array from many smaller, monolithic apertures. By doing this, one can expect to obtain higher
spatial resolution than from existing monolithic apertures. Since it is difficult to recover absolute phase of an
optical field, it is desirable to form the synthetic aperture without interfering the light from the sub-apertures.
This paper demonstrates a method of forming images using pupil plane intensity measurements of coherently
illuminated scenes; a low resolution image will also be used to supply a starting estimate for the algortihm. From
this data model, a maximum likelihood estimator is formed.
Laser systems are finding a home in many military applications - such as Space Situational Awareness, imaging and weapons systems. With an increasing focus on programs that entail atmospheric propagations, there is a need for a cost effective method of performing laboratory proof-of-concept demonstrations. The use of one SLM (single phase screen) to model atmospheric effects has been investigated previously with promising results. However, some effects cannot be captured with a single SLM. This paper focuses on the addition of a second SLM and quantifying the results. Multiple screens will allow the user to independently control the Fried parameter, the isoplanatic angle, and Rytov Variance. The research is comprised of simulation and experiment. The simulation demonstrates the ability to accurately model atmospheric effects with two phase screens. Based on the simulation, a hardware implementation was tested in the lab. The results of this research show promise, however some issues remain. This thesis describes the experimental set-up and results based on measurement of phase and intensity of the propagated field. It was noted that while analytic results are replicated in simulation, similar results in the lab were difficult to achieve.