Subscriber access provided by UNIV OF CAMBRIDGE
External strain enabled post-modification of nanomembrane-based optical microtube cavities Jiawei Wang, Yin Yin, Qi Hao, Shaozhuan Huang, Ehsan Saei Ghareh Naz, Oliver G. Schmidt, and Libo Ma ACS Photonics, Just Accepted Manuscript • DOI: 10.1021/acsphotonics.7b01601 • Publication Date (Web): 04 Apr 2018 Downloaded from http://pubs.acs.org on April 4, 2018
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Photonics
External strain enabled post-modification of nanomembrane-based optical microtube cavities Jiawei Wang †, Yin Yin†, Qi Hao†, Shaozhuan Huang†, Ehsan Saei Ghareh Naz†, Oliver G. Schmidt†,‡ and Libo Ma† † Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany ‡ Material Systems for Nanoelectronics, Technische Universität Chemnitz, 09111 Chemnitz, Germany
KEYWORDS: strained nanomembrane, microtube cavity, whispering gallery mode, resonant mode tuning
ABSTRACT:
Optical microtube cavities formed by self-rolling of pre-strained nanomembranes feature unique optical resonance properties for both fundamental and applied research. A post-fabrication treatment of the microcavities made of rolled-up nanomembranes is attractive in order to better manipulate and control the optical modes therein. Here, we report a new approach of modifying
ACS Paragon Plus Environment
1
ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 2 of 31
the resonant modes by applying external strain using a stretchable polymer substrate. The properties of both azimuthal and higher order axial modes are systematically investigated by varying external strain along the tube axial direction. The post-treatment process leads to a spectral redshift and improvement of quality factors, which is attributed to a modification of tube shape and interlayer compactness. For tubes with axial confinement, the measurements suggest that both the eigenenergies and mode spatial distributions of optical axial modes get significantly modified after applying the external strain. Our numerical calculation results show good agreement with the experimental results. This work reports a simple and robust strain-based modification scheme for manipulating the resonant mode energies, mode spacing, and mode field distributions.
Nanomembranes made of dielectric materials have been proven a fascinating platform for novel research in nanophotonics.1,2 Over the development of more than one decade, rolled-up microtubular structures have been extensively explored with developed applications ranging from optical microcavities3-5, generation of optical Berry phase,6 metamaterials,7 cell culture scaffolds,8 rolled up electrodes9, rolled up photodetectors10 to micro-engines.11 The rolled-up nanotech allows mass-production of microtubular structures with well-defined size, position and orientation on a substrate. Optical microtube cavities formed by rolled-up nanomembranes naturally support whispering gallery mode (WGM) resonances with the strong evanescent field at the boundaries of ultrathin cavity walls (~100-300 nm), which facilitates the study of pronounced light-matter interactions and thus enables ultra-sensitive bio-chemical detection.4,1214
Notably, the well-controlled sub-wavelength wall thickness is a unique and outstanding feature
ACS Paragon Plus Environment
2
Page 3 of 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Photonics
compared with other reported tubular-shaped optical microcavities, including aluminosilicate microtubes,15 ZnO hexagonal microtubes16 and silica microcapillaries,17 where highly non-trivial challenges are faced to reach sub-micron cavity wall thickness. Besides, rolled-up microtubes also feature other various properties of merit, including i) hollow-core structures enabling labin-a-tube-based analytical applications;12,18 ii) a convenient way of integrating optical gain media (e.g., luminescent quantum dots,19,20 quantum wells nanostructures,
23
21
and organic molecules22) and plasmonic
iii) a maturing monolithic integration scheme with integrated planar photonic
waveguide and devices.24 Compared to other traditional WGM cavities (e.g., microdisks, microtoroids, and microspheres), the Q-factor of microtubes is relatively low (
