ECE News Story
Krishnaprasad Research Team Receives Patent for Wavefront Sensors
Professor P.S. Krishnaprasad (ECE/ISR), ISR Research Professor Mikhail Vorontsov, ISR Assistant Research Scientist Eric Justh, Dr. Leonid I. Beresnev (Army Research Laboratory), and Dr. Jennifer Ricklin (Army Research Laboratory) have been awarded U.S. Patent 6,911,637 for “Wavefront phase sensors using optically or electrically controlled phase spatial light modulators.”
These systems and methods for optical wavefront sensing and control are based on a phase-contrast Fourier-domain filtering technique. Wavefront phase sensing is accomplished using an optically or electronically controlled phase spatial light modulator (SLM) as a Fourier-domain filter. Examples of optically controlled phase SLMs include (1) liquid crystal light valve (LCLV); (2) micro-electromechanical system (MEMS) micromirror array used in conjunction with a photodetector array; and (3) pixelized liquid-crystal device used in conjunction with a photodetector array.
The direct adaptive optic feedback system approach is capable of high-resolution real-time correction of atmospheric turbulence-induced wavefront phase aberrations. The disclosed wavefront sensors could be used with conventional low-resolution adaptive-optic wavefront correction hardware based on deformable mirrors or multi-electrode wavefront phase modulators.
The invention also includes a wavefront sensor, the "Differential Zernike Filter." This device uses the difference between two intensity measurements corresponding to equal but oppositely-directed zero-order spectral component phase shifts to produce a high visibility wavefront sensor output that is particularly well-suited for use in the direct adaptive optic feedback system.
July 18, 2005