Coupled Whispering Gallery Mode Resonators via Template‐Assisted Assembly of Photoluminescent Microspheres

Journal Article · 28 May 2019 · Advanced Functional Materials

DOI: https://doi.org/10.1002/adfm.201902520 · OSTI ID:1518525

Smith, Marcus J. ^[1]; Zeng, Qingji ^[2]; Lafalce, Evan ^[2]; Yu, Shengtao ^[3]; Zhang, Shuaidi ^[3]; Vardeny, Zeev Valy ^[2]; Tsukruk, Vladimir V.  ^[3]

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1. School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA, Air Force Research Labs‐Aerospace Systems Directorate WPAFB OH 45433 USA
2. Department of Physics and Astronomy University of Utah Salt Lake City UT 84112 USA
3. School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA

Abstract This study reports a facile method for the assembly of large, array style, coupled dye‐doped microsphere resonators by template‐assisted, in which an aqueous suspension of colloidal microspheres assemble on a patterned template. By exploiting the high resolution of 3D (two‐photon) lithography derived templates, closely packed large arrays, hundreds to thousands of dimers with controlled gap spacing, only limited by the size of the substrate can be achieved. Dye‐doped emissive microspheres with Q ‐factors >2.5 × 10 ² can be achieved and trapped into predetermined cavity positions, thereby controlling the distance between adjacent microspheres. This design allows to scale down dimer spacing from usual 400 nm for traditional photolithography to very small spacing of 50 nm. It is found that exciting individual microspheres in the ensemble shows intense optical cavity modes, whereas closely coupled pairs show controlled mode splitting. Coupling between photoluminescent microspheres is strongly influenced by the gap distance, with strong coupling, equating to normal mode splitting, arising as the gap distance is reduced below traditional sub‐micrometer scale. The coupled dimer assemblies are promising candidates for advancing the development of large‐area coupled nanophotonic structures, beyond the spatial resolution‐limited photolithographical derived arrays.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0002232
• OSTI ID: 1518525
• Journal Information: Advanced Functional Materials, Journal Name: Advanced Functional Materials Journal Issue: 30 Vol. 29; ISSN 1616-301X
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English