Abstract
A laser device (250) for generating a helical-shaped optical wave and comprising: (i) a gain region (203) located between one first end defined by a first mirror (202) and a second end defined by an exit region, (ii) a second mirror (206) arranged so as to form with the first mirror (202) an optical cavity including the gain region (203) and a gap (207) between the exit region and the second mirror (206), (iii) means for pumping the gain region (203) so as to generate the optical wave, wherein the laser device (250) further comprises at least one means for shaping the light intensity and/or phase profiles of the optical wave and arranged for selecting at least one rotary-symmetrical transverse mode of the optical wave, said rotary-symmetrical transverse mode being chosen between those with a radial index equal to zero and with an azimuthal index being an integer with a module higher or equal to 1.