Afocal beam steering system corrected for excess diffraction due to phase error from microelectromechanical mirror offsets

A method for sharpening a received or projected beam of substantially coherent radiation that is directionally guided by an array of microelectromechanical mirrors;

• said method comprising the steps of:
• interposing a function that tends to counteract phase difference between rays reflected from adjacent mirrors of the array;
• and
• causing the interposed function to vary with mirror angle:
• wherein:
• the interposing and causing steps comprise having a second array of microelectromechanical mirrors disposed in optical series with the first-mentioned array, and controlled to introduce an opposite and compensating phase difference as a function of mirror angle.

Apparatus for receiving a beam of substantially coherent radiation that is directionally guided by an array of microelectromechanical mirrors;

• said apparatus comprising:
• in a path of said radiation, a physical nonlinear phase-shift device that introduces a first phase shift and optically convolves said first phase shift with other phase shifts introduced by the mirror array;
• and
• means for deconvolving the first phase shift and said other phase shifts, to extract a substantially unshifted signal.