A wavefront sensor is a device for measuring the aberrations of an optical wavefront. Although an amplitude splitting interferometer such as the Michelson interferometer could be called a wavefront sensor, the term is normally applied to instruments that do not require an unaberrated reference beam to interfere with. They are commonly used in adaptive optics systems, lens testing and increasingly in ophthalmology.
There are several types of wavefront sensors, including:
References
Wavefront sensor Wikipedia(Text) CC BY-SA