Abstract: A semiconductor laser element includes a first emitter having a first active layer and a first guide layer, and a second emitter having a second active layer and a second guide layer. A thickness of the first emitter is different from a thickness of the second emitter so that an average value of an index DB1 and an index DB2 represented by equations (1) and (2) is 5% or less, [Equation 1] DB1=?|F1(?)?F01(?)|d???(1) [Equation 2] DB2=?|F2(?)?F02(?)|d???(2) F1(?) is a far field pattern when it is assumed that only the first emitter is present, and F2(?) is a far field pattern when it is assumed that only the second emitter is present. F01(?) is a far field pattern of one of two modes corresponding to a fundamental mode of the light emitted from the first and second emitters, and F02(?) is a far field pattern of the other one.

Abstract: A light emitter is a light emitter for converting incident electrons into light, and includes a multiple quantum well structure for generating the light by incidence of the electrons, and an electron incident surface provided on the multiple quantum well structure. A certain barrier layer included in a plurality of barrier layers constituting the multiple quantum well structure is thicker than another barrier layer included in the plurality of barrier layers and located on the electron incident surface side with respect to the certain barrier layer.