3 August 1999 Finite outer scale considerations for beam-steering optimization
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Finite turbulence outer scale attenuates turbulence power at low spatial frequencies, providing a finite variance for turbulence-induced phase. The temporal properties of low spatial-frequency aberrations such as tilt are affected directly by finite outer scale turbulence models. When optical estimation techniques are used in beam-steering applications, the estimator form and its performance are related directly to the correlative properties of tilt and higher-order modes as determined by the value of Lo/D. In this work, we consider the effect of finite turbulence outer scale on the performance of optical tilt compensation incorporating time-delayed tilt plus higher-order modes. The results indicate that while smaller values of Lo/D provide for higher Strehl ratios after tilt compensation, the Strehl ratio gain obtained through optimal compensation is reduced with decreasing values of Lo/D. For the relative aperture diameter D/r0 equals 5 and using time-delayed tilt plus higher-order modes through Zernike 15, the Strehl ratio gain with time delay vr/D equals 0.5 is approximately 15 for L0D equals 100. Under the same conditions, the Strehl ratio gain for L0D equals 2 is approximately 3.
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Matthew R. Whiteley, Matthew R. Whiteley, "Finite outer scale considerations for beam-steering optimization", Proc. SPIE 3706, Airborne Laser Advanced Technology II, (3 August 1999); doi: 10.1117/12.356974; https://doi.org/10.1117/12.356974

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