Laser device with a beam carrying controlled orbital angular momentum

A laser device for generating a helical-shaped phase optical wave, the laser device comprising:

• a gain region located between one first end defined by a first mirror and a second end defined by an exit region;
• a second mirror configured to form, with the first mirror, an optical cavity including the gain region and a gap between the exit region and the second mirror;
• means for pumping the gain region so as to generate the optical wave;
• at least one means for transverse filtering the optical wave configured for selecting at least one rotary-symmetrical transverse mode of the optical wave, said rotary-symmetrical transverse mode being chosen among those with a radial index equal to zero and with an azimuthal index being an integer with a module higher or equal to 1;
• and
• the at least one means for transverse filtering the optical wave comprises the following functionalized areas:
• a center-discoidal area providing high losses between a minimum phase shift value and a maximum phase shift value, and
• a first annular area, located around the center-longitudinal axis and a second annular area located around the first annular area, wherein said first annular area and said second annular area each provide modal azimuthal graded phase shift;
• and
• a functionalized absorbing area or pumping area, located on a peripheral region, which is outside of the first annular area.