A light emitter according to one embodiment has a fiber shape. And it includes a core portion containing a light emitting material, the material absorbing excitation light and emitting light having a wavelength longer than a wavelength of the excitation light. And also it includes a clad portion provided outside the core portion, the clad portion having a first region and second regions, the second regions being periodically formed in the first region, the second regions having a refractive index higher than a refractive index of a first region, the refractive index of the first region being equal to or higher than a refractive index of the core portion.