PROBLEM TO BE SOLVED: To obtain a 2-dimensional photonic crystalline plane luminescence laser wherein a surface-emitted light is a linearly polarized light of unimodal nature and a Q value is high.
SOLUTION: The photonick crystal periodic structures 21 composed of second medium are arranged in an active layer (first medium) 12 which emits light by carrier implantation, or in the vicinity of the layer 12, where the first medium and the second medium are different in refractive index. Grid structure of photonic crystal 20 is tetragonal lattice or rectangular lattice, and has translation symmetry although it has not rotation symmetry. Alternately, grid structure of the photonick crystal 20 is tetragonal lattice or rectangular lattice and one out of pl, pm, pg or cm in a classification method of 2-dimensional pattern. The form of lattice point is nearly triangular most preferably.