Bismuth plasmonics for extraordinary light absorption in deep sub-wavelength geometries


Ozbay I., Ghobadi A., BÜTÜN B., Turhan-Sayan G.

OPTICS LETTERS, cilt.45, ss.686-689, 2020 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 45 Konu: 3
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1364/ol.45.000686
  • Dergi Adı: OPTICS LETTERS
  • Sayfa Sayıları: ss.686-689

Özet

In this Letter, we demonstrate an ultra-broadband metamaterial absorber of unrivaled bandwidth (BW) using extraordinary optical response of bismuth (Bi), which is the material selected through our novel analysis. Based on our theoretical model, we investigate the maximum metal- insulator-metal (MIM) cavity BW, achievable by any metal with known n-k data. We show that an ideal metal in such structures should have a positive real permittivity part in the near-infrared (NIR) regime. Contrary to noble and lossy metals utilized by most research groups in the field, this requirement is satisfied only by Bi, whose data greatly adhere to the ideal material properties predicted by our analysis. A Bi nanodisc-based MIM resonator with an absorption above 0.9 in an ultra-broadband range of 800 nm-2390 nm is designed, fabricated, and characterized. To the best of our knowledge, this is the broadest absorption BW reported for a MIM cavity in the NIR with its upper-to-lower absorption edge ratio exceeding best contenders by more than 150%. According to the findings in this Letter, the use of proper materials and dimensions will lead to realization of deep sub-wavelength efficient optical devices. (C) 2020 Optical Society of America