An organic distributed feedback layer, which comprises a resonator in a double layer structure comprising a photo-induced mass transfer material layer and an organic fluorescence layer, provided as an under layer below the former layer, where the photo-induced mass transfer material is a polymer material having an azobenzene skeleton represented by the following chemical structure: ##STR00001## has such a characteristic that the laser emission wavelength is programmable by changing interference exposure conditions for forming gratings of the photo-induced mass transfer material.