Laser eye surgery system

An imaging system includes an eye interface device, a scanning assembly, a beam source, a free-floating mechanism, and a detection assembly. The eye interface device interfaces with an eye. The scanning assembly supports the eye interface device and scans a focal point of an electromagnetic radiation beam within the eye. The beam source generates the electromagnetic radiation beam. The free-floating mechanism supports the scanning assembly and accommodates movement of the eye and provides a variable optical path for the electronic radiation beam and a portion of the electronic radiation beam reflected from the focal point location. The variable optical path is disposed between the beam source and the scanner and has an optical path length that varies to accommodate movement of the eye. The detection assembly generates a signal indicative of intensity of a portion of the electromagnetic radiation beam reflected from the focal point location.