Surface emitting laser and optical coherence tomography apparatus including the same

A surface emitting laser comprising:

• a lower reflector, an active layer, and an upper reflector that are arranged in that order;
• an air gap provided between the active layer and the upper reflector;
• and
• a slab provided on an optical path of the air gap and having a refractive index that differs from a refractive index of the air gap,
• wherein at least one of the upper reflector and the lower reflector is configured so as to be movable in an optical axis direction so that a wavelength of emitted light changes in accordance with a change in a position of the at least one of the upper reflector and the lower reflector in the optical axis direction,
• wherein, in the case where the position of the upper reflector is changed, a center of the slab in the optical axis direction is located between any antinode of a standing wave formed in the air gap and a node of the standing wave on an upper-reflector side of the antinode,
• wherein, in the case where the position of the lower reflector is changed, the center of the slab in the optical axis direction is located between any antinode of the standing wave formed in the air gap and a node of the standing wave on a lower-reflector side of the antinode, and
• wherein an optical thickness of the slab in the optical axis direction is in a range of greater than 0 and smaller than ½ a center wavelength of the surface emitting laser, or is the sum of an optical thickness in the range and half an integral multiple of the center wavelength.