Search for: All records

Image resolution and field of view in far-field optical microscopy are often inversely proportional to one another due to digital sampling limitations imposed by the magnification of the system and the pixel size of the sensor. We present a method including a spatial shifting mechanism and a reconstruction algorithm that bypasses this trade-off by shifting the sample to be imaged by subpixel increments, before registering the images via phase correlation and combining the resulting registered images using the shift-and-add approach. Importantly, this method requires no specific optical components that are uncommon to commercially available or custom-built microscope systems. The findings of the presented study demonstrate an improvement to spatial resolution of ∼42% while maintaining the system’s field of view (FOV), leading to a more than twofold improvement to the system’s space–bandwidth product (SBP). 

The concept of remote epitaxy involves a two-dimensional van der Waals layer covering the substrate surface, which still enable adatoms to follow the atomic motif of the underlying substrate. The mode of growth must be carefully defined as defects, e.g., pinholes, in two-dimensional materials can allow direct epitaxy from the substrate, which, in combination with lateral epitaxial overgrowth, could also form an epilayer. Here, we show several unique cases that can only be observed for remote epitaxy, distinguishable from other two-dimensional material-based epitaxy mechanisms. We first grow BaTiO₃on patterned graphene to establish a condition for minimizing epitaxial lateral overgrowth. By observing entire nanometer-scale nuclei grown aligned to the substrate on pinhole-free graphene confirmed by high-resolution scanning transmission electron microscopy, we visually confirm that remote epitaxy is operative at the atomic scale. Macroscopically, we also show variations in the density of GaN microcrystal arrays that depend on the ionicity of substrates and the number of graphene layers. 

Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but high remnant polarization has hindered their effective deployment in energy storage applications. Previous methodologies have encountered problems because of the deteriorated crystallinity of the ferroelectric materials. We introduce an approach to control the relaxation time using two-dimensional (2D) materials while minimizing energy loss by using 2D/3D/2D heterostructures and preserving the crystallinity of ferroelectric 3D materials. Using this approach, we were able to achieve an energy density of 191.7 joules per cubic centimeter with an efficiency greater than 90%. This precise control over relaxation time holds promise for a wide array of applications and has the potential to accelerate the development of highly efficient energy storage systems. 

In this work, we present a zero knowledge argument for general arithmetic circuits that is public-coin and constant rounds, so it can be made non-interactive and publicly verifiable with the Fiat-Shamir heuristic. The construction is based on the MPC-in-the-head paradigm, in which the prover jointly emulates all MPC protocol participants and can provide advice in the form of Beaver triples whose accuracy must be checked by the verifier. Our construction follows the Beaver triple sacrificing approach used by Baum and Nof [PKC 2020]. Our improvements reduce the communication per multiplication gate from 4 to 2 field elements, matching the performance of the cut-and-choose approach taken by Katz, Kolesnikov, and Wang [CCS 2018] and with lower additive overhead for some parameter settings. We implement our protocol and analyze its cost on Picnic-style post-quantum digital signatures based on the AES family of circuits.