a high resolution optical scanner is disclosed for scanning a light beam onto a receiving medium . the scanner includes a light source for generating a light beam , optical means for anamorphically shaping the beam , and a rotatable polygon for moving the light beam through a predetermined scan angle . in order to obtain high resolution throughout a scan line , a mirror , having power in the tangential plane and in the sagittal plane , is positioned to intercept the beam from the polygon and direct it to the receiving medium .