Abstract: An optical system (100) comprises focusing optics (10) configured to produce a focusing beam (B) at a focal region (Fr). The focusing optics (10) 5 comprise a set of spherical surfaces (11s, 12s) configured to introduce a respective spherical aberrations into the focusing beam (B). The spherical aberrations are tuned to maximize a length (Lr) of the focal region (Fr). The system comprises at least one rotatable element (22) configured to redirect the focusing beam (B) along a variable beam direction. A gradient index 10 plate (31) is configured to receive the beam from the rotatable element (22) and linearize a dependence of a radial coordinate (R) of the focused beam in a target plane (P) as function of an angle of rotation (?) of the rotatable element (22). Advantageously, the gradient index plate is flat and so does not introduce further aberrations which may interfere with the focusing function.

Abstract: Disclosed is a laser marking system for marking an object, comprising a laser source, an optical system, and a targeting system. The laser source configured to generate a laser beam. The optical system comprises a first optical element and a second optical element. The first optical element is configured to receive the laser beam. The laser source and the optical system are configured to have the laser beam illuminate a predetermined illumination area of the first optical element. The first optical element is shaped to introduce spherical aberrations in the received laser beam, resulting in an intermediate beam produced by the first optical element. The second optical element is arranged at a predetermined distance from the first optical element and configured to receive the intermediate beam. The second optical element is shaped to introduce further spherical aberrations in the received intermediate beam, resulting in the generation of an essentially non-diffractive beam.