Theory and experiment of phasing detection by use of two wavelengths

摘要

Wavefront sensing in monochromatic light has 2 pi ambiguity. To resolve this ambiguity, the wavefront sensing is performed in two wavelengths. A new algorithm is proposed to find the correct phase, and the algorithm is verified by simulation. Using the algorithm, the capture range of a wavefront sensor can be extended from on the order of lambda/2 in a segmented mirror piston error to several waves. Lastly, a co-phasing experiment system of the segmented mirror is built to verify the algorithm. In the experiment, one wavelength is 0.65 mu m, and the other is 0.636 mu m. After the co-phasing fine tuning of the segmented mirror, the piston error of the segmented mirror is better than lambda/20. (C) 2016 Optical Society of America