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2019 年度 実績報告書

極細光ファイバの近接場偏光解析

研究課題

研究課題/領域番号 18F18367
研究機関沖縄科学技術大学院大学

研究代表者

NICCHORMAIC SILE  沖縄科学技術大学院大学, 量子技術のための光・物質相互作用ユニット, 教授 (10715288)

研究分担者 TKACHENKO GEORGIY  沖縄科学技術大学院大学, 量子技術のための光・物質相互作用ユニット, 外国人特別研究員
研究期間 (年度) 2018-11-09 – 2021-03-31
キーワードoptical nanofiber / polarization control / directional coupling / whispering gallery mode / optomechanical probe / two-photon atomic spectroscopy
研究実績の概要

This year, we have published (Physical Review Applied) the key paper that established our method for the complete control of polarization at the waist of a single-mode optical nanofiber. In this paper, we study near-field directional coupling between crossed nanofibers. The sum and difference of optical power in the counterpropagating modes of the output fiber depend on the polarization state of light at the waist region of the input fiber. This dependence allowed us to reverse the unknown polarization change produced by the tapered fiber before the waist, thus achieving the complete control over the polarization at the waist by means of a free-space compensator.
In the following project, we have combined the crossed nanofibers with a whispering-gallery-mode microcavity to achieve ten-fold enhancement of the directional coupling between the nanofibers (ACS Photonics).
Further, we have realized the polarization compensation via far-field imaging of the light escaping from the nanofiber waist due to scattering of the guided mode from natural nanoscale imperfections of the fiber shape or material. This light, imaged by a lens with a high enough numerical aperture, allows us to adjust the polarization compensator, without the need for a near-field probe (Journal of Optics).
This contactless method has been applied for achieving accurate polarization control in two experimental studies: light-induced orbiting of dielectric microparticles around a single-mode nanofiber (Optica), and nanofiber-based two-photon spectroscopy for cold rubidium atoms (in process).

現在までの達成度 (区分)
現在までの達成度 (区分)

1: 当初の計画以上に進展している

理由

Originally, we planned to use a nanofabriacted plasmonic probe to perform in-situ polarimetry of the evanescent field around an optical nanofiber. By exploring directional coupling between two crossed nanofibers, we found that a nanofiber itself can serve as a simple and efficient near-field probe for the polarization state. This finding has advanced our work significantly, since a nanofiber can be quickly and precisely fabricated without the need for clean room facilities. The further achievement of cavity-enhanced directional coupling was an unexpected result as well.
Our plan was to apply the near-field polarization control in optomechanical experiments with colloidal particles near a single-mode nanofiber, and perhaps in atomic experiments, if a nanoprobe could be placed and manipulated inside a high-vacuum chamber where the laser-cooled atomic cloud is prepared and interrogated. The success of the contactless polarization compensation based on scattering imaging allowed us to conveniently and accurately control polarization for nanofibers in both above experimental environments.

今後の研究の推進方策

In FY2020, we plan to publish the finished study on nanofiber-based two-photon spectroscopy for cold rubidium atoms. We will also use the imaging-based method for controlling polarization in an ongoing experimental study aimed at optomechanical detection of transverse spin angular momentum of light. In this study, the transverse spin is a feature of the evanescent field around an optical nanofiber. We are probing the spin by observing its direct mechanical action on a probe dielectric particle held and spun by optical tweezers next to a nanofiber waist.

  • 研究成果

    (7件)

すべて 2020 2019

すべて 雑誌論文 (4件) (うち国際共著 4件、 査読あり 4件、 オープンアクセス 4件) 学会発表 (3件)

  • [雑誌論文] Enhanced Directional Coupling of Light with a Whispering Gallery Microcavity2020

    • 著者名/発表者名
      Fuchuan Lei, Georgiy Tkachenko, Xuefeng Jiang, Jonathan M. Ward, Lan Yang, and Sile Nic Chormaic
    • 雑誌名

      ACS Photonics

      巻: 7 ページ: 361, 365

    • DOI

      10.1021/acsphotonics.9b01611

    • 査読あり / オープンアクセス / 国際共著
  • [雑誌論文] Light-induced rotation of dielectric microparticles around an optical nanofiber2020

    • 著者名/発表者名
      Georgiy Tkachenko, Ivan Toftul, Cindy Esporlas, Aili Maimaiti, Fam Le Kien, Viet Giang Truong, and Sile Nic Chormaic
    • 雑誌名

      Optica

      巻: 7 ページ: 59, 62

    • DOI

      10.1364/OPTICA.374441

    • 査読あり / オープンアクセス / 国際共著
  • [雑誌論文] Complete Polarization Control for a Nanofiber Waveguide Using Directional Coupling2019

    • 著者名/発表者名
      Fuchuan Lei, Georgiy Tkachenko, Jonathan M. Ward, and Sile Nic Chormaic
    • 雑誌名

      Physical Review Applied

      巻: 11 ページ: 064041

    • DOI

      10.1103/PhysRevApplied.11.064041

    • 査読あり / オープンアクセス / 国際共著
  • [雑誌論文] Polarisation control for optical nanofibres by imaging through a single lens2019

    • 著者名/発表者名
      Georgiy Tkachenko, Fuchuan Lei and Sie Nic Chormaic
    • 雑誌名

      Journal of Optics

      巻: 21 ページ: 125604

    • DOI

      10.1088/2040-8986/ab5204

    • 査読あり / オープンアクセス / 国際共著
  • [学会発表] Polarization control for single-mode optical nanofibers: fundamentals and applications2020

    • 著者名/発表者名
      Georgiy Tkachenko
    • 学会等名
      SPIE Photonics West, OPTO: Complex Light and Optical Forces XIV
  • [学会発表] Controlling Polarization in Optical Nanofibers Using Directional Coupling of Light2019

    • 著者名/発表者名
      Georgiy Tkachenko
    • 学会等名
      International Conference on Nano-photonics and Nano-optoelectronics
  • [学会発表] Controlling polarization in optical nanofibers using directional coupling of light2019

    • 著者名/発表者名
      Fuchuan Lei
    • 学会等名
      ONNA: Optical Nanofibre Applications

URL: 

公開日: 2021-01-27  

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