The Naval Research Laboratory has developed a new method for generating atmospheric turbulence and a testbed that
simulates its aberrations far more inexpensively and with greater fidelity using a Liquid Crystal (LC) Spatial Light
Modulator (SLM) than many other methods. This system allows the simulation of atmospheric seeing conditions ranging
from very poor to very good and different algorithms may be easily employed on the device for comparison. These
simulations can be dynamically generated and modified very quickly and easily. In addition, many models for simulating
turbulence often neglect temporal transitions along with different seeing conditions. Using the statistically independent
set of Karhunen-Loeve polynomials in conjunction with Kolmogorov statistics in this model provides an accurate spatial
and temporal model for simulating turbulence. An added benefit to using a LC SLM is its low cost; and multiple devices
can be used to simulate multiple layers of turbulence in a laboratory environment. Current testing with using multiple LC
SLMs is under investigation at the Naval Research Laboratory and the Naval Postgraduate School.
The Air Force Research Laboratory is developing a Self-Referencing Interferometer (SRI) wavefront sensor (WFS) for applications requiring laser propagation in strong scintillation. This paper compares several phase-shifting techniques that can be used to capture interference patterns and examines their effects on SRI WFS performance. These techniques include temporal, spatial, and spatial-temporal phase shifting. Temporal phase shifting allows for straightforward setup, alignment, and calibration, though its performance is degraded by changes in the atmosphere between measurements. Spatial phase shifting effectively "freezes" the atmosphere, but requires more rigorous camera calibration and alignment. Spatial-temporal phase shifting balances the benefits and challenges of both methods. This paper includes a discussion of the tradeoffs involved in selecting an appropriate phase-shifting approach for a given application. Laboratory results demonstrate the advantages and disadvantages of each technique in evaluation of SRI WFS performance.