Wafer-scale nanofabrication of sub-5 nm gaps in plasmonic metasurfaces.

In the rapidly evolving field of plasmonic metasurfaces, achieving homogeneous, reliable, and reproducible fabrication of sub-5 nm dielectric nanogaps is a significant challenge. This article presents an advanced fabrication technology that addresses this issue, capable of realizing uniform and reliable vertical nanogap metasurfaces on a whole wafer of 100 mm diameter. By leveraging fast patterning techniques, such as variable-shaped and character projection electron beam lithography (EBL), along with atomic layer deposition (ALD) for defining a few nanometer gaps with sub-nanometer precision, we have developed a flexible nanofabrication technology to achieve gaps as narrow as 2 nm in plasmonic nanoantennas.

Mid-infrared dielectric laser acceleration in a silicon dual pillar structure.

Dielectric laser accelerators use near-infrared laser pulses to accelerate electrons at dielectric structures. Driving these devices with mid-infrared light should result in relaxed requirements on the electron beam, easier fabrication, higher damage threshold, and thus higher acceleration gradients. In this paper, we demonstrate dielectric laser acceleration of electrons driven with 10 μm light in a silicon dual pillar structure.

Structured illumination ptychography and at-wavelength characterization with an EUV diffuser at 13.5 nm wavelength.

Structured illumination is essential for high-performance ptychography. Especially in the extreme ultraviolet (EUV) range, where reflective optics are prevalent, the generation of structured beams is challenging and, so far, mostly amplitude-only masks have been used. In this study, we generate a highly structured beam using a phase-shifting diffuser optimized for 13.

Antireflection Structures for VIS and NIR on Arbitrarily Shaped Fused Silica Substrates with Colloidal Polystyrene Nanosphere Lithography.

Antireflective (AR) nanostructures offer an effective, broadband alternative to conventional AR coatings that could be used even under extreme conditions. In this publication, a possible fabrication process based on colloidal polystyrene (PS) nanosphere lithography for the fabrication of such AR structures on arbitrarily shaped fused silica substrates is presented and evaluated. Special emphasis is placed on the involved manufacturing steps in order to be able to produce tailored and effective structures.

Enhancement of third harmonic generation induced by surface lattice resonances in plasmonic metasurfaces.

We investigate experimentally third harmonic generation (THG) from plasmonic metasurfaces consisting of two-dimensional rectangular lattices of centrosymmetric gold nanobars. By varying the incidence angle and the lattice period, we show how surface lattice resonances (SLRs) at the involved wavelengths are the major contributors in determining the magnitude of the nonlinear effects. A further boost on THG is observed when we excite together more than one SLR, either at the same or at different frequency.