The apparatus for selectively transmitting the spectrum of electromagnetic radiation within a predefined wavelength range is provided with a carrier (115), a pinhole diaphragm which is arranged above the carrier (115) and is made of a material that is substantially impermeable to the radiation of interest, wherein the pinhole diaphragm has at least one radiation passage opening with a size for allowing through radiation at a wavelength which is less than or equal to a predefinable upper limit wavelength, and an electrically insulating and optically transparent dielectric layer (103) which is formed on the carrier (115) inside the radiation passage opening and extends, in a manner adjoining the radiation passage opening, between the carrier (115) and at least one section below the pinhole diaphragm. The dielectric layer (103) has a thickness which is less than or equal to half a predefinable lower limit wavelength which is less than the upper limit wavelength.