Surface emitting quantum cascade laser

A surface emitting quantum cascade laser comprising:

• an active layer including a plurality of quantum well layers stacked therein and being capable of emitting laser light by intersubband transition;
• a first semiconductor layer provided on the active layer and having a first surface, the first surface including an internal region in which first pits constitute a first two-dimensional grating and an outer peripheral region in which second pits constitute a second two-dimensional grating, the outer peripheral region surrounding the internal region:
• an insulator layer which covers side surfaces and bottom surfaces of the first pits, side surfaces and bottom surfaces of the second pits, and a portion of the internal region not provided with the first pits;
• an upper electrode which covers a portion of the outer peripheral region not provided with the second pits and fills the first pits and the second pits via the insulator layer;
• a second semiconductor layer provided on a surface of the active layer on opposite side from a surface provided with the first semiconductor;
• and
• a lower electrode which is provided on a surface of the second semiconductor layer on opposite side from the active layer side, and is provided with an opening including a portion of the internal region in plan view,
• a first planar shape of opening ends of the first pits being asymmetric with respect to a line passing through barycenter of the first planar shape and being parallel to at least one side of the first two-dimensional grating.