Total absorption of visible light in ultrathin weakly absorbing semiconductor gratings

Björn C P Sturmberg*, Teck K. Chong, Duk Yong Choi, Thomas P. White, Lindsay C. Botten, Kokou B. Dossou, Christopher G. Poulton, Kylie R. Catchpole, Ross C. McPhedran, C. Martijn de Sterke

*Corresponding author for this work

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The perfect absorption of light in subwavelength thickness layers generally relies on exotic materials, metamaterials or thick metallic gratings. Here we demonstrate that total light absorption can be achieved in ultra-thin gratings composed of conventional materials, including relatively weakly-absorbing semiconductors, which are compatible with optoelectronic applications such as photodetectors and optical modulators. We fabricate a 41 nm thick antimony sulphide grating structure that has a measured absorptance of A = 99.3% at a visible wavelength of 591 nm, in excellent agreement with theory. We infer that the absorption within the grating is A = 98.7%, with only A = 0.6% within the silver mirror. A planar reference sample absorbs A = 7.7% at this wavelength.

Original languageEnglish
Article number259171
Pages (from-to)556-562
Number of pages7
JournalOptica
Volume3
Issue number6
DOIs
Publication statusPublished - 20 Jun 2016
Externally publishedYes

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