Patent ID: 8379685

Claim:
A surface emitting laser comprising a two-dimensional photonic crystal that includes a resonance mode in an in-plane direction, wherein the two-dimensional photonic crystal includes two primitive translation vectors of a primitive translation vector a 1 and a primitive translation vector a 2 , which extend in different directions, the resonance mode includes at least a resonance mode resonating in a direction in which the primitive translation vector a 1 extends and a resonance mode resonating in a direction in which the primitive translation vector a 2 extends, the primitive translation vector a 1 has a length |a 1 |, the primitive translation vector a 2 has a length |a 2 |, the length |a 1 | satisfies a relational expression |a 1 |=p×(λ 1 /2n eff1 ) that is described by a resonance wavelength λ 1 in the resonance mode in the a 1 direction, an effective refractive index n eff1 determined by the resonance mode in the a 1 direction, and an integer p of 2 or more, the length |a 2 | satisfies a relational expression |a 2 |=λ 2 /2n eff2 that is described by a resonance wavelength λ 2 in the resonance mode in the a 2 direction and an effective refractive index n eff2 determined by the resonance mode in the a 2 direction, and the resonance wavelength λ 1 and the resonance wavelength λ 2 satisfy a relational expression λ 2 ≦2×(n eff2 /(n out +n eff2 ))×λ 1 that is described by the effective refractive index n eff2 and a refractive index n out of an external medium located out of the surface emitting laser.