Gonidec, Mathieu, Hamedi, Mahiar M., Nemiroski, Alex, Rubio, Luis M., Torres, Cesar, and Whitesides, George McClelland
Quick submit: 2017-01-11T15:09:35-0500 Gonidec, Mathieu, Mahiar M. Hamedi, Alex Nemiroski, Luis M. Rubio, Cesar Torres, and George M. Whitesides. 2016. Fabrication of Nonperiodic Metasurfaces by Microlens Projection Lithography. Nano Letters 16, no. 7: 4125–4132. doi:10.1021/acs.nanolett.6b00952.
This paper describes a strategy that uses template-directed self-assembly of µm-scale microspheres to fabricate arrays of microlenses for projection photolithography of periodic, quasiperiodic, and aperiodic infrared metasurfaces. This method of “template-encoded microlens projection lithography” (TEMPL) enables rapid prototyping of planar, multi-scale patterns of similarly shaped structures with critical dimensions down to ~ 400 nm. Each of these structures is defined by local projection lithography, with a single microsphere acting as a lens. This paper explores the use of TEMPL for the fabrication of a broad range of two-dimensional lattices with varying types of non-periodic spatial distribution. The matching optical spectra of the fabricated and simulated metasurfaces confirm that TEMPL can produce structures that conform to expected optical behavior. Chemistry and Chemical Biology
Nemiroski, Alex, Gonidec, Mathieu, Fox, Jerome Michael, Jean-Remy, Philip, Turnage, Evan, and Whitesides, George McClelland
Nemiroski, Alex, Mathieu Gonidec, Jerome M. Fox, Philip Jean-Remy, Evan Turnage, and George M. Whitesides. 2014. “Engineering Shadows to Fabricate Optical Metasurfaces.” ACS Nano 8 (11) (November 25): 11061–11070. doi:10.1021/nn504214b.
Optical metasurfaces—patterned arrays of plasmonic nanoantennas that enable the precise manipulation of light–matter interactions—are emerging as critical components in many nanophotonic materials, including planar metamaterials, chemical and biological sensors, and photovoltaics. The development of these materials has been slowed by the difficulty of efficiently fabricating patterns with the required combinations of intricate nanoscale structure, high areal density, and/or heterogeneous composition. One convenient strategy that enables parallel fabrication of periodic nanopatterns uses self-assembled colloidal monolayers as shadow masks; this method has, however, not been extended beyond a small set of simple patterns and, thus, has remained incompatible with the broad design requirements of metasurfaces. This paper demonstrates a technique—shadow-sphere lithography (SSL)—that uses sequential deposition from multiple angles through plasma-etched microspheres to expand the variety and complexity of structures accessible by colloidal masks. SSL harnesses the entire, relatively unexplored, space of shadow-derived shapes and—with custom software to guide multiangled deposition—contains sufficient degrees of freedom to (i) design and fabricate a wide variety of metasurfaces that incorporate complex structures with small feature sizes and multiple materials and (ii) generate, in parallel, thousands of variations of structures for high-throughput screening of new patterns that may yield unexpected optical spectra. This generalized approach to engineering shadows of spheres provides a new strategy for efficient prototyping and discovery of periodic metasurfaces. Chemistry and Chemical Biology