Optical device and method for providing two offset laser beams

A method for providing at least a first and a second laser beam spatially offset with respect to an input laser beam, the method comprising:

• providing a laser source for generating said input laser beam such that said input laser beam has a fixed polarization in time;
• providing a spatial offsetting unit for producing an offset laser beam with respect to said input laser beam, said offset laser beam having a main propagation axis A, and being suitable for describing a circle in a plane perpendicular to this main propagation axis A, said spatial offsetting unit configured to maintain the same polarization between said input laser beam and said offset laser beam;
• providing a separating unit comprising a first polarization separation means for obtaining from said offset laser beam:
• the first spatially offset laser beam by transmission having a first main propagation axis, and
• the second laser beam spatially offset by reflection having a second main propagation axis;
• said separating unit being configured such that said first and second spatially offset laser beams are suitable for describing a circle in a plane perpendicular to said first and second main propagations axes respectively.