Wavelength selective wideband uncooled infrared sensor using a two-dimensional plasmonic absorber

Abstract

A wavelength selective wideband uncooled infrared (IR) sensor that detects middle-wavelength and long-wavelength IR (MWIR and LWIR) regions has been developed using a two-dimensional plasmonic absorber (2-D PLA). The 2-D PLA has a Au-based 2-D periodic dimple-array structure, where photons can be manipulated using a spoof surface plasmon. Numerical investigations demonstrate that the absorption wavelength can be designed according to the surface period of dimples over a wide wavelength range (MWIR and LWIR regions). A microelectromechanical system-based uncooled IR sensor with a 2-D PLA was fabricated using complementary metal oxide semiconductor and micromachining techniques. Measurement of the spectral responsivity shows that the selective enhancement of responsivity is achieved over both MWIR and LWIR regions, where the wavelength of the responsivity peak coincides with the dimple period of the 2-D PLA. The results provide direct evidence that a wideband wavelength selective IR sensor can be realized simply by design of the 2-D PLA surface structure without the need for vertical control in terms of gap or thickness. A pixel array where each pixel has a different detection wavelength could be developed for multicolor IR imaging.