DUAL-FREQUENCY VERTICAL-EXTERNAL-CAVITY SURFACE-EMITTING LASER DEVICE FOR THz GENERATION AND METHOD FOR GENERATING THz

A laser device for generating an optical wave comprising at least two frequencies, such laser device comprising:

• a first element 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, distinct from the first element, and arranged so as 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;
• means for shaping the light intensity of the optical wave arranged for selecting at least two transverse modes of the optical wave, said means for shaping the light intensity comprise at least one mask, each mask being patterned with a surface having a non-uniform absorbance, said surface including at least one absorbing area and/or at least one transmitting area;
• and
• means for shaping a longitudinal and/or transversal phase profile of the optical wave and arranged for adjusting at least two transverse modes of the optical wave, said means for shaping the phase profile comprise at least one photonic crystal and/or diffraction grating located at least one end of the gain region and patterned in order to shape the transverse phase and/or the transverse intensity of the optical wave.