The present application relates to a cutting head (1) for a device for cutting hair. The cutting head has an optical system (3) which directs a laser beam (7) across a cutting zone (8) in the cutting head. The laser beam has a fast and a slow axis. The optical system has a focus lens (6) configured to form a first focal point (11) of the laser beam in the cutting zone. In one embodiment, the optical system (3) also has a focusing element (15) which refocuses the laser beam to form a second focal point (16) of the laser beam in the cutting zone. In another embodiment, the focus lens forms a focal length of the laser beam in the cutting zone along its fast axis which is greater than a focal length of the laser beam in the cutting zone along its slow axis.