Device and method for focusing a light beam

A device for focusing a light beam, comprising:

• an optical assembly comprising at least one focusing lens and/or mirror;
• a support structure which supports the optical assembly;
• a magnetic actuator configured to move the optical assembly with respect to the support structure along a moving direction substantially parallel to an optical axis of the optical assembly;
• at least one position sensor configured to provide an indication of the position of said optical assembly with respect to said support structure;
• wherein the magnetic actuator comprises:
• at least one permanent magnet integrally associated with one of the optical assembly and the support structure;
• at least one first electrical winding integrally associated with the other one of the optical assembly and the support structure and configured to allow a passage of an electric current that interacts with said at least one permanent magnet and causes a movement of the optical assembly along said moving direction until the optical assembly is brought to a desired focusing position;
• and
• at least one second electrical winding integrally associated with the other one of the optical assembly and the support structure and configured to be short-circuited so as to generate, due to an electromagnetic induction generated by a relative motion between said at least one permanent magnet and said at least one second electrical winding, a braking force that opposes the movement of the optical assembly along said moving direction, and wherein said at least one permanent magnet is integrally associated with the support structure and said at least one first electrical winding and at least one second electrical winding are integrally associated with the optical assembly, and said at least one permanent magnet integrally associated with one of the optical assembly and the support structure comprises two permanent magnets facing each other, wherein said at least one first electrical winding and said at least one second electrical winding are at least partially interposed between the two permanent magnets.