FIELD: optics. SUBSTANCE: given optical system incorporates light source, plane-parallel plates placed in relative symmetric position with reference to plane perpendicular to optical axis of light source, photodetector detecting light reflected from optical recording medium and cylindrical lens. Cylindrical lens is located between light source and plane-parallel plates. First plane-parallel plate on which light beam falls from cylindrical lens lets this beam pass through and reflects light beam reflected from optical recording medium towards photodetector. EFFECT: enhanced efficiency of usage of light beam and minimal aberration of wave front. 28 cl, 8 dwg
