Geometrically Tunable Beamed Light Emission from a Quantum‐Dot Ensemble Near a Gradient Metasurface

Journal Article · 20 February 2020 · Advanced Optical Materials

DOI: https://doi.org/10.1002/adom.201901951 · OSTI ID:1601012

Wang, Xiaowei ^[1]; Li, Yuyu ^[1]; Toufanian, Reyhaneh ^[2]; Kogos, Leonard C. ^[1]; Dennis, Allison M. ^[2]; Paiella, Roberto  ^[1]

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1. Department of Electrical and Computer Engineering and Photonics Center Boston University 8 Saint Mary's Street Boston MA 02215 USA
2. Department of Biomedical Engineering and Division of Materials Science and Engineering Boston University 8 St. Mary's St. Boston MA 02215 USA

Abstract Optical metasurfaces have been widely investigated in recent years as a means to tailor the wavefronts of externally incident light for passive device applications. At the same time, their use in active optoelectronic devices such as light emitters is far less established. This work explores their ability to control the radiation properties of a nearby continuous ensemble of randomly oriented incoherent dipole sources via near‐field interactions. Specifically, a film of colloidal quantum dots is deposited on a plasmonic metasurface consisting of a 1D array of metallic nanoantennas on a metal film. The array is designed to introduce a linear phase profile upon reflection, and a bi‐periodic nanoparticle arrangement is introduced to ensure adequate sampling of the desired phase gradient. Highly directional radiation patterns are correspondingly obtained from the quantum dots at an enhanced emission rate. The underlying radiation mechanism involves the near‐field excitation of surface plasmon polaritons at the metal film, and their selective diffractive scattering by the metasurface into well‐collimated beams along predetermined geometrically tunable directions. These results underscore the distinctive ability of metasurfaces to control radiation properties directly at the source level, which is technologically significant for the continued miniaturization and large‐scale integration of optoelectronic devices.

• Sponsoring Organization: USDOE
• OSTI ID: 1601012
• Journal Information: Advanced Optical Materials, Journal Name: Advanced Optical Materials Vol. 8 Journal Issue: 8; ISSN 2195-1071
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Germany
• Language: English