Two infrared emission modes with different wavelengths and orthogonal polarization in a waveguide thermal emitter

This study investigates a Au/SiO2/Au waveguide thermal emitter incorporating a metallic grating embedded in the SiO2 layer. The metal grating acts as a beam splitter, dividing the device into two waveguide structures determined by the polarization of the waveguide modes. The thermal radiation spectrum exhibits two peaks with orthogonal polarization. The emitted wavelengths of the two waveguide modes can be adjusted by controlling the thickness of the SiO2 layers on both sides of the metallic grating during the fabrication process. The emission peaks have ratios of the full width at half maximum to the peak wavelength of 0.057 and 0.05 for the TE and TM polarizations, respectively. These characteristics show the suitability of the device for multi-peaks and narrow bandwidth infrared light source applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757034]