An inspection system includes a first focusing unit configured to perform fast focus changes to a first focusing function applied to an incident light beam. A traveling lens acousto-optic device is arranged to receive the light beam focused by the first focusing function and produce focused spots using a plurality of traveling lenses generated in response to radio frequency signals. The traveling lenses apply a second focusing function and the traveling lens acousto-optic device is arranged to alter the second focusing function at a fast rate. The inspection system also includes optics arranged to direct the focused spots onto an inspected object and to direct radiation from the inspected object to a sensor.