We have experimentally and theoretically developed a unique thermally stimulated midinfrared source that emits radiation within a narrow range of wavelengths (δλ/λ⩽0.2). The emission wavelengths are defined by the periodicity of a metal coated silicon–air photonic crystal etched into the emitter surface. The lattice of the holes in the metal mediate the coupling of light into discrete surface plasmon states. This yields surfaces with spectrally nonuniform infrared reflection properties where over much of the IR 90+% of photons are reflected yet, in a narrow spectral region, 90% absorption is observed. Transfer matrix calculations simulate well the position and strength of the absorption features. This technology will afford tunable infrared emitters with high power in a narrow spectral band that are critical for sensing, spectroscopy, and thermophotovoltaic applications.

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A metallodielectric architecture is employed to readily tailor the spectral properties of a bulk material for application to infrared sources and spectroscopic sensors. We exploit the interaction between surface plasmons at a metal interface with a photonic crystal in silicon to control the spectral response of the surface in reflection, absorption, and emission. The design uses Si-based thermally isolated suspended bridge structures fabricated using conventional photolithography techniques. The tunable narrow spectral response is defined by the symmetry and periodicity of the metallodielectric photonic crystal. Individual subresonances are recognized within this bandwidth. We model their origin through calculations of surface-plasmon modes in the metallic grating overlayer. Periodic arrays of holes in thin metal layers lead to coupled plasmons at the two metal–dielectric interfaces that, in turn, couple to modes in the underlying silicon–air photonic crystal. The model provides crucial physical insight into the interaction between surface plasmons and photonic crystals, with good agreement with the experimental results.

We have simulated metallo-dielectric photonic crystals that are sharp thermal emitters at infrared wavelengths, and are being employed in gas sensors. The simulations were performed with a rigorous scattering matrix approach where Maxwell's equations are solved in Fourier space. These metallo-dielectric photonic crystals consist of a sub-wavelength hole array in a metal layer coupled to a two-dimensional photonic crystal of the same periodicity. The sub-wavelength hole array has an enhanced transmission mode that couples to a guided mode of the photonic crystal. The transmissive mode of the hole array is absorbed by the photonic crystal to create a sharp absorption and reflective minimum feature found for a range of lattice spacing. The structure thermally emits in a narrow band of wavelengths controlled by the lattice spacing that can be tuned over the infrared region. The underlying physics of this emissive device is modeled with rigorous scattering matrix simulations.

Metallo-dielectric photonic crystals are sharp thermal emitters at infrared wavelengths, and are being employed in sensors. We describe the theory of thermal emission and enhanced absorption in these photonic crystals using a scattering matrix approach, where Maxwell's equations are solved in Fourier space. A sub-wavelength hole array in a metal layer is coupled to a two-dimensional photonic crystal of the same periodicity in these metallo-dielectric photonic crystals. The sub-wavelength hole array has an enhanced transmission mode that couples to a weakly guided mode of the photonic crystal having similar modal character. The transmissive mode of the hole array is absorbed by the photonic crystal to create a sharp absorption and reflective minimum. The enhanced absorption is investigated in different lattice symmetries.