Photonic-crystal based concave mirror for highly coherent stable external-cavity semiconductor laser

Summary form only given. Achieving highly coherent high power semiconductor lasers requires the use of spatially stable and high finesse cavities, which are usually realized using commercial dielectric concave mirrors in a concave-type stable cavity; another solution is to use the thermal lens to approach a stable Laguerre-Gauss or Hermite-Gauss laser cavity, but this is difficult to control, furthermore it introduces aberrations in the laser beam, moreover the two solutions are very limiting if we want to add some functionalities to the mirror like beam shaping, polarization control...etc.polarization control...etc. Among many other functionalities, Photonic crystals (PC) can allow a precise control of the transverse phase and intensity profile; in this work we demonstrate a low-loss, high reflectivity and aberrations free concave mirror for single mode operation, in planar semiconductor technology, for highly coherent high power external cavity semiconductor laser using a 2D PC on Bragg mirror. We demonstrated that Vertical External Cavity Surface Emitting Laser (VECSEL) is a very promoting laser technology to achieve compact highly coherent high power semiconductor laser, with a beam shaping PC-based planar mirror in a short mm long cavity.