Quantum emitters such as the diamond nitrogen-vacancy (NV) center are the basis for a wide range of quantum technologies. However, refraction and reflections at material interfaces impede photon collection, and the emitters’ atomic scale necessitates the use of free space optical measurement setups that prevent packaging of quantum devices. To overcome these limitations, we design and fabricate a metasurface composed of nanoscale diamond pillars that acts as an immersion lens to collect and collimate the emission of an individual NV center. The metalens exhibits a numerical aperture greater than 1.0, enabling efficient fiber-coupling of quantum emitters. This flexible design will lead to the miniaturization of quantum devices in a wide range of host materials and the development of metasurfaces that shape single-photon emission for coupling to optical cavities or route photons based on their quantum state.

Corrugated paper cardboard provides an everyday example of a lightweight, yet rigid, sandwich structure. Here we present nanocardboard, a monolithic plate mechanical metamaterial composed of nanometer-thickness (25–400 nm) face sheets that are connected by micrometer-height tubular webbing. We fabricate nanocardboard plates of up to 1 centimeter-square size, which exhibit an enhanced bending stiffness at ultralow mass of ~1 g m−2. The nanoscale thickness allows the plates to completely recover their shape after sharp bending even when the radius of curvature is comparable to the plate height. Optimally chosen geometry enhances the bending stiffness and spring constant by more than four orders of magnitude in comparison to solid plates with the same mass, far exceeding the enhancement factors previously demonstrated at both the macroscale and nanoscale. Nanocardboard may find applications as a structural component for wings of microflyers or interstellar lightsails, scanning probe cantilevers, and other microscopic and macroscopic systems.

This article introduces in archival form the Nanolithography Toolbox, a platform-independent software package for scripted lithography pattern layout generation. The Center for Nanoscale Science and Technology (CNST) at the National Institute of Standards and Technology (NIST) developed the Nanolithography Toolbox to help users of the CNST NanoFab design devices with complex curves and aggressive critical dimensions. Using parameterized shapes as building blocks, the Nanolithography Toolbox allows users to rapidly design and layout nanoscale devices of arbitrary complexity through scripting and programming. The Toolbox offers many parameterized shapes, including structure libraries for micro-and nanoelectromechanical systems (MEMS and NEMS) and nanophotonic devices. Furthermore, the Toolbox allows users to precisely define the number of vertices for each shape or create vectorized shapes using Bezier curves. Parameterized control allows users to design smooth curves with complex shapes. The Toolbox is applicable to a broad range of design tasks in the fabrication of microscale and nanoscale devices.

Articles you may be interested inEfficient proximity effect correction method based on multivariate adaptive regression splines for grayscale ebeam lithography Proximity effect correction using pattern shape modification and area density map for electron-beam projection lithography J.Dose, shape, and hybrid modifications for PYRAMID in electron beam proximity effect correction It is well known that cold development yields higher contrast and improved exposure latitude particularly for ZEP520 from Zeon Chemicals. In this paper, the authors quantify the effective process blur as a function of temperature. The effective process blur for our development process conditions were found to be 10, 42, and 71 nm for developer temperatures at À12, 21, and 30 C, respectively. Knowledge of how to tune the process blur can be used in a unique application. Instead of using the best possible process blur, exposure latitude is traded for improved exposure time. Optimizing the e-beam exposure time is always desired while maintaining a target critical dimension and desired shape at the wafer. In particular, the exposure time can be dominated by shape overhead delays stemming from the over digitization of curved shapes within a pattern. As such, it is better to expose a pattern with the least number of shapes as possible while obtaining the desired shape at the wafer. The authors demonstrate how e-beam simulation can be used to determine the optimal effective process blur to obtain a target desired shape while minimizing the fractured shape count to ultimately reduce overall exposure time.

Designs patterned by electron beam lithography without applying process effect correction exhibit overexposed dense features and underexposed sparse features for most practical exposure scenarios. This is typified by the limited exposure latitude of hydrogen silsesquioxane resist on silicon-on-insulator substrates used for silicon photonics, which commonly display very high density features (vertical grating couplers, ring resonators) mixed with very sparse features (inverse tapered waveguides, lone waveguides) in a single pattern. The authors have optimized a proximity effect correction (PEC) based on our analysis of a single 1D process control monitor characterization sample. Our PEC verification sample, which includes electron backscatter and process-related microloading effects, achieved linewidths with an RMS error of ±5.0 nm for features with pattern densities spanning 1%–67%. Ignoring the pattern density-dependent microloading effect limits the resolvable pattern density span to a smaller range and degrades the linewidth error.