Narrow Bandwidth Midinfrared Waveguide Thermal Emitters

This work describes innovative waveguide thermal emitters with top metal perforated with subwavelength holes arranged in a short period to eliminate Bragg scattered waveguide modes (WMs) and surface plasmon polariton (SPP) modes. A metal-dielectric-metal parallel-plate waveguide with top metal perforated with subwavelength holes arranged in a short period exhibits high output intensities and emission peaks (WMs) with a narrow bandwidth in the midinfrared region under heat treatment. The redundant SPP modes and Bragg scattered WMs are filtered automatically by shifting them to the short wavelength due to a short period where blackbody radiations are too weak to appear.