Three Dimensional Turbulence Measurement System based on Green`s Function Inversion

Optical Physics Company (OPC) has developed a technique called Green`s Function Inversion (GFI) to compensate for moderate to severe deep turbulence effects encountered by tactical laser weapons. This technique can also be used to accurately measure the 3D turbulence profile in air-to-air and air-to-ground engagements. The GFI approach provides comprehensive turbulence data that goes beyond the current parameters of the Fried parameter, isoplanatic angle, and scintillation by determining the 3D turbulence phase profile versus time. The measured data can then be used to construct a physics-based model of turbulence distributions, anisotropies, inner and outer scale and inhomogeneities. The end result is a well anchored turbulence model which can accurately predict the effect of turbulence on a laser wavefront. During Phase I, we will set up a lab demonstration that sends a laser beam through phase plates that have been well characterized and measure the Green`s function. We will use the sensor data to calculate the phase screen positions and 2D profiles. The estimated phase screen positions and profiles will be compared to the measured screen data for scoring the accuracy. During Phase II, we intend to build and test outdoors a prototype to characterize turbulence along extended paths. BENEFIT: The GFI Turbulence Sensor has been developed to provide a major leap in our understanding of turbulence phenomena and how to model them analytically. If successful, the proposed system would be critically important to the success of current and future lasercom and tactical HEL systems by enabling them to predict and optimize performance to a much higher accuracy. The project is being formulated to serve immediate needs, with the assistance of our commercialization partner Boeing, which is a key high energy laser provider to the defense industry.