An emitter for emitting electromagnetic radiation, comprising: a first region configured for thermally generating electromagnetic radiation, wherein the first region includes a first photonic crystal of the type having a hexagonal or square first periodical structure with first holes having a first dimension (d 1) and being at a first periodicity (a 1), so as to define a first dimension-to-periodicity ratio, the first photonic crystal of the first region being in high-doped semiconductor material, and electrodes electrically connected to the first photonic crystal so as to generate the electromagnetic radiation, wherein the first photonic crystal has a bandgap in its optical dispersion, characterized by a second region configured for filtering the electromagnetic radiation generated in the first region, wherein the second region includes a second photonic crystal of the type having a hexagonal or square second periodical structure with second holes having a second dimension (d 2) and being at a second periodicity (a 2), so as to define a second dimension-to-periodicity ratio, the second photonic crystal of the second region being in undoped semiconductor material or low-doped semiconductor material, wherein the second dimension-to-periodicity ratio is different from the first dimension-to-periodicity ratio, and wherein the second photonic crystal has a bandgap in its optical dispersion, and wherein the first photonic crystal and the second photonic crystal are in contact with each other and are manufactured starting from one single piece such that the birthplace and the filtering of the electromagnetic radiation happen in a same platform and not in multiple, different devices. a first region configured for thermally generating electromagnetic radiation, wherein the first region includes a first photonic crystal of the type having a hexagonal or square first periodical structure with first holes having a first dimension (d 1) and being at a first periodicity (a 1), so as to define a first dimension-to-periodicity ratio, the first photonic crystal of the first region being in high-doped semiconductor material, and electrodes electrically connected to the first photonic crystal so as to generate the electromagnetic radiation, characterized by a second region configured for filtering the electromagnetic radiation generated in the first region, wherein the second region includes a second photonic crystal of the type having a hexagonal or square second periodical structure with second holes having a second dimension (d 2) and being at a second periodicity (a 2), so as to define a second dimension-to-periodicity ratio, the second photonic crystal of the second region being in undoped semiconductor material or low-doped semiconductor material, wherein the second dimension-to-periodicity ratio is different from the first dimension-to-periodicity ratio, and wherein the second photonic crystal has a bandgap in its optical dispersion, and wherein the first photonic crystal and the second photonic crystal are in contact with each other and are manufactured starting from one single piece such that the birthplace and the filtering of the electromagnetic radiation happen in a same platform and not in multiple, different devices.