The L01 is a sensor head for the PICOSCALE Interferometer. The target beam is focused along only one axis with a cylinder lens so that a line focus is generated. This way, the sensor head has a relatively large angular working range along the focused axis while having a large diameter along the orthogonal axis. Typically, these sensor heads are used to measure eccentric movements of rotating cylindrical objects and being insensitive to their wobble, i.e. tip/tilt of the axis of rotation.