Wave-front analysis using Fresnel lens arrays

A compact wave-front sensor is implemented by an array of two-beam common path inversion interferometers. Each element of the array consists of two Fresnel lenses in a confocal configuration. The wave-front data can be extracted from a superposition of the zero-order undiffracted wave and the twice-diffracted first-order wave. The result is a high-sensitivity, compact, and stable interferometric wave-front sensor.