New modal wave-front sensor: a theoretical analysis

We present a new design of a modal wave-front sensor capable of measuring d irectly the Zernike components of an aberrated wave front. The sensor shows good linearity for small aberration amplitudes and is particularly suitabl e for integration in a closed-loop adaptive system. We introduce a sensitiv ity matrix and show that it is sparse, and we derive conditions specifying which elements are necessarily zero. The sensor may be temporally or spatia lly multiplexed, the former using a reconfigurable optical element, the lat ter using a numerically optimized binary optical element. Different optimiz ation schemes are discussed, and their performance is compared. (C) 2000 Op tical Society of America [S0740-3232(00)00206-4].