Abstract: A thermal emitter device, including a thermal emitting membrane including a surface, wherein the membrane can be heated to a thermal emission temperature so that the surface radiates IR or visible light, wherein the emissivity of the surface is lower than 0.7. A lens includes a surface facing the surface of the membrane, and has a reflectivity normal to the lens surface included in the range 4% to 40%, to partially reflect the radiated IR or visible light, wherein the distance between the lens surface and the surface is equal or lower than L/4, where L is a major length of the membrane. A part of the IR or visible light reflected by the lens is reabsorbed by the membrane, and another part of the IR or visible light reflected by the lens is reflected by the membrane toward the lens, having therefore another chance to go through the lens.

Abstract: An IR radiator element suitable for use as a miniature infrared emitter (micro-hotplate) in a gas sensor, IR-spectrometer or electron microscope. The micro-hotplate comprises a plate supported by multiple support arms. The plate and arms are fabricated as a MEMS device comprising a single contiguous piece of electrically-conducting refractory ceramic such as hafnium carbide (HfC) or tantalum hafnium carbide (TaHfC). Each of the arms, in addition to providing structural cantilever support for the plate (2), acts as a heating element for the plate. The plate is heated by applying a voltage across the arms. The arms may also be shaped to absorb thermomechanical stress which arises during the heating and cooling of the arms and plate. The plate, which may have an area of less than 0.05 mm2 and a thickness of between 1% and 10% of the largest dimension of the plate, for example, can be heated to 4,000 K or more and cooled again with a duty cycle of as little 0.