Large Area Metasurface Lenses in the NIR Region

Kenney, M. G. et al. (2019) Large Area Metasurface Lenses in the NIR Region. In: SPIE Optical Metrology, Munich, Germany, 24-27 Jun 2019, 110570C. (doi: 10.1117/12.2527157)

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Metasurfaces have revolutionized the definition of compact optics. Using subwavelength periodic structures of nanostructured dielectrics, the refractive index and absorption properties of metasurfaces – which are 2D metamaterials – can manipulate light to a degree not possible with conventional bulk glasses and crystals. The phase, polarization, spin (for circularly polarized light), amplitude and wavelength of light can all be manipulated and crafted to user-specified values to mimic the action of a lens, which we refer to as a metalens (ML). MLs have four major advantages over traditional refractive lenses – superior resolution, lighter weight, miniaturization and cost. Many metasurfaces with useful functionalities have been proposed in recent years, yet although novel in their approach have few real-world applications. One such market is the use within infrared laser systems, such as laser designators. In this work, we demonstrate metasurface lenses working at a wavelength of λ = 1064 nm, with aperture d = 1 mm and four different Fnumbers (focal length f = 0.5, 1, 2 and 5 mm). The lenses are composed of 700nm high a-Si pillars – ranging from 70- 360 nm diameter – which are fabricated using electron beam lithography (EBL) and reactive ion etching processes, on top of a fused silica substrate. Such lenses are shown to have diffraction-limited performance, with focal spot-size agreeing with theoretical values of λ‧f/d. Furthermore, we have designed large area lenses with aperture d = 10 mm, where the number of pillars per lens exceeds 550 million. By using an efficient Python script, we are able to produce these 100 mm2 samples with just 14 hours of EBL writing time.

Item Type:Conference Proceedings
Glasgow Author(s) Enlighten ID:Grant, Dr James and Cumming, Professor David and Mills, Mr Gordon and Sorel, Professor Marc and Docherty, Mr Kevin and Hao, Miss Danni and Kenney, Dr Mitchell Guy
Authors: Kenney, M. G., Grant, J., Hao, D., Docherty, K., Mills, G., Jeffrey, G., Macleod, D., Henry, D., MacKay, P., Sorel, M., Lamb, R. A., Cumming, D., Bodermann, B., Frenner, K., and Silver, R. M.
College/School:College of Science and Engineering > School of Engineering
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Proceedings of SPIE
Publisher:Society of Photo-optical Instrumentation Engineers
Published Online:21 June 2019
Copyright Holders:Copyright © 2019 SPIE
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
Data DOI:10.5525/gla.researchdata.838

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
588331Triple wavelength superspectral camera focal-plane array (SUPERCAMERA)David CummingEngineering and Physical Sciences Research Council (EPSRC)EP/J018678/1ENG - ENGINEERING ELECTRONICS & NANO ENG
6672319UK Quantum Technology Hub in Enhanced Quantum ImagingMiles PadgettEngineering and Physical Sciences Research Council (EPSRC)EP/M01326X/1S&E P&A - PHYSICS & ASTRONOMY