MEMS-based plasmon infrared emitter with hexagonal hole arrays perforated in the Al-SiO2-Si structure

A micro-machined plasmon infrared emitter with hexagonal hole arrays perforated in the Al/SiO2/Si structure is presented. The silicon-on-insulator wafer was employed to fabricate the hexagonal photonic crystal infrared emitters using micro-electro-mechanical system (MEMS) technology. The Al/SiO2/Si structure perforated with periodic hexagonal hole arrays was resistively heated using direct-current voltage to active the boron-doped silicon membranes. The electrical characteristics and emission spectrum of infrared emitters under different excited voltage conditions were measured. Additionally, the reflection, transmission and absorption of light were also characterized to reveal the mechanism of narrowband-enhanced emission. The experimental results indicate that the surface plasmon polaritons (SPPs) caused by the diffraction of the thermal radiation impinge on the metal-dielectric grating and play an essential role in the extraordinary optical transmission and enhanced emission of subwavelength hole arrays. The constructive interference between the thermal radiation and the SPPs enriches the emission spectrum on the condition that the phase match relation is satisfied. It is demonstrated from the measured results of modulation performance and thermal imaging of emitters that the thickness of membranes and the thermal isolation between membranes and supporting frame structure have a significant influence on the modulation rate, emission intensity and the suppression of the background emission.