The disclosure concerns an infrared emitter is provided comprising a metalized membrane emitting infrared light in operation. The membrane comprises a two dimensional array of infrared wavelength sized through-holes and to each side a thin metal layer comprising also an array of through-holes. The through-holes are arranged as a two-dimensional periodic array and each of said through-holes have a cross section having a maximum and a minimum dimension of less than any wavelength of the emitted infrared light. The peak wavelength of the emitted infrared light is proportional to the periodicity of the through-holes. At least one of the metal layers is connected to an electrical current source that provides an electrical current that heats at least one of the metal layers so that a narrow bandwidth and highly directive light beam of infrared light is emitted. The membrane is arranged on a membrane support and both are made of a material that resists to temperatures higher than 400.

A method of manufacturing carburized Lu.sub.2O.sub.3 doped Mo cathodes for thermionic emission for magnetrons is described. The Lu.sub.2O.sub.3 doped Mo powder is prepared by sol-gel method. The powder is reduced thoroughly in hydrogen atmosphere. Afterwards, the powder is die-pressed into pellets, followed by sintering in hydrogen and carburization in activated carbon powder to obtain the carburized Lu.sub.2O.sub.3 doped Mo cathode.

An optical radiation source produced from a disordered semiconductor material, such as black silicon, is provided. The optical radiation source includes a semiconductor substrate, a disordered semiconductor structure etched in the semiconductor substrate and a heating element disposed proximal to the disordered semiconductor structure and configured to heat the disordered semiconductor structure to a temperature at which the disordered semiconductor structure emits thermal infrared radiation.

Embodiments of the present invention generally relate to a tubular lamp with a coiled filament having an overwind wrapped around the coil. In one embodiment, the tubular lamp has a coiled coil filament, and the coiled coil has an overwind wrapped around the coiled coil.

Embodiments of the present invention generally relate to a tubular lamp with a coiled filament having an overwind wrapped around the coil. In one embodiment, the tubular lamp has a coiled coil filament, and the coiled coil has an overwind wrapped around the coiled coil.