Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors

Justin M. Foley; Jamie D. Phillips

doi:10.1117/12.2014532

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15 March 2013 Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors

Justin M. Foley, Jamie D. Phillips

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Proceedings Volume 8633, High Contrast Metastructures II; 863310 (2013) https://doi.org/10.1117/12.2014532
Event: SPIE OPTO, 2013, San Francisco, California, United States

Abstract

We report broadband reflectance in the long-wavelength infrared (LWIR, 8-12 μm) utilizing suspended-Si, high-index-contrast subwavelength gratings (HCGs). Iterative design optimization using finite element analysis software has been performed accounting for silicon’s wavelength-dependent index of refraction and extinction coefficient. Grating arrays were fabricated using commercial silicon-on-insulator (SOI) substrates, photolithography and reactive ion etching; subsequent selective wet etching of SiO₂ was used to provide suspended Si/air gratings. Fourier transform infrared (FTIR) spectroscopy demonstrates broadband, polarization–dependent reflectance between 8.5 and 12 μm, which agrees with the simulated response.

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Justin M. Foley and Jamie D. Phillips "Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors", Proc. SPIE 8633, High Contrast Metastructures II, 863310 (15 March 2013); https://doi.org/10.1117/12.2014532

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