Holographic wavefront sensing for atmospheric turbulence using Karhunen-Loève decomposition

Holographic wavefront sensing (HWS) has been proposed as a solution to overcome the main limitations that traditional Shack-Hartmann sensors: low bandwidth and sensitivity to scintillation. However, the accuracy of HWS is compromised due to presence of intermodal crosstalk effects which limit the sensor's performance considerably. In this paper, we propose the use of the Karhunen-Loève (K-L) functions as a new basis in which the aberrated wavefronts are decomposed and we provide experimental results of the measured intermodal crosstalk. We evaluate the sensor's performance in the presence of emulated atmospheric turbulence and provide a comparison between sensors based on either Zernike or K-L decompositions. Additionally, we show first experimental results from a HWS using K-L for measuring simulated atmospheric turbulence.