Presentation + Paper
21 June 2019 Large area metasurface lenses in the NIR region
Mitchell Kenney, James Grant, Danni Hao, Kevin Docherty, Gordon Mills, Graham Jeffrey, Donald Macleod, David Henry, Peter MacKay, Marc Sorel, Robert A. Lamb, David R. S. Cumming
Author Affiliations +
Abstract
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.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mitchell Kenney, James Grant, Danni Hao, Kevin Docherty, Gordon Mills, Graham Jeffrey, Donald Macleod, David Henry, Peter MacKay, Marc Sorel, Robert A. Lamb, and David R. S. Cumming "Large area metasurface lenses in the NIR region", Proc. SPIE 11057, Modeling Aspects in Optical Metrology VII, 110570C (21 June 2019); https://doi.org/10.1117/12.2527157
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CITATIONS
Cited by 1 scholarly publication.
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KEYWORDS
Lenses

Electron beam lithography

Dielectrics

Amorphous silicon

Near infrared

Nanostructures

Refractive index

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