LIGHT SOURCE INCLUDING EFFECTIVE REFRACTIVE INDEX CONTROLLING PATTERN

Provided is a light source. The light source includes a substrate, a light emitting layer provided on the substrate and configured to emit light, and a plurality of unit structures provided on the light emitting layer, wherein the unit structures are arranged along a radial direction and a tangential direction to form an effective refractive index controlling pattern, wherein the effective refractive index controlling pattern is configured to control the effective refractive index through a first variable defined by a width of each of the unit structures, a second variable defined as a period in which the unit structures are arranged in the tangential direction, a third variable defined as a period in which the unit structures adjacent in the radial direction are arranged, and a fourth variable defined as a difference between a refractive index of the unit structures and a refractive index of a material surrounding the unit structures, wherein the first variable is smaller than a central wavelength of the light emitted from the light emitting layer, wherein the effective refractive index controlling pattern has rotational symmetry.