Patent ID: 8242527

Claim:
A light emitting device for generating infrared light, the light emitting device comprising: a substrate having a first surface; a first metal layer formed on the first surface of the substrate; a dielectric layer formed on the first metal layer, wherein a thickness of the dielectric layer is greater than a particular value; and a second metal layer formed on the dielectric layer; wherein when the light emitting device is heated, the dielectric layer has a waveguide mode such that the infrared light generated by the light emitting device is transmitted in the dielectric layer, and a wavelength of the infrared light generated in the waveguide mode relates to the thickness of the dielectric layer; wherein the second metal layer has at least one first hole, the at least one first hole makes the dielectric layer have a surface plasma mode when the light emitting device is heated, and a wavelength of the infrared light generated in the surface plasma mode is different from a wavelength of the infrared light generated in the waveguide mode.