Carbon Nanotubes Coupled with Silica Toroid Microcavities as Emitters for Silicon-Integrated Photonics

Ren Tokunaga, Kotomi Kinoshita, Riku Imamura, Keigo Nagashima, Ryouhei Imafuku, Kenta Nakagawa, Takasumi Tanabe, Hideyuki Maki

Research output: Contribution to journalArticlepeer-review


A light source based on single-walled carbon nanotubes (SWNTs) is one of the promising candidates for a microsized light source on a silicon chip at telecommunication wavelengths in optical communications and optical interconnects. However, SWNT-based light emitters possess the disadvantage of having a very broad emission spectrum. Here, we present an ultranarrow-linewidth photoluminescence (PL) emitter based on a silica toroid resonator, along with SWNTs, on a silicon chip. We simultaneously managed both excitation and emission lights at telecommunication wavelengths on a silicon chip by employing a very simple in-line configuration consisting of a toroid resonator and a tapered fiber for light input and output. Owing to the extremely high Q factor of our silica toroid resonator, we obtained an ultrahigh Q factor (∼2.1 × 104) of C-band PL emission. We also demonstrated strong PL emission under laterally polarized excitation conditions owing to the strong coupling to the toroid resonator, and laterally polarized PL emission can be selectively generated independently of the excitation polarization direction. This SWNT-based PL emitter based on a simple system with a silica toroid resonator can open routes to highly integrated photonics and optoelectronics on silicon-based platforms.

Original languageEnglish
Pages (from-to)14328-14335
Number of pages8
JournalACS Applied Nano Materials
Issue number10
Publication statusPublished - 2022 Oct 28


  • carbon nanotubes
  • high Q factor
  • micro-resonator
  • photoluminescence
  • silica toroid resonator

ASJC Scopus subject areas

  • General Materials Science


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