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.
View Article and Find Full Text PDFStrategically designed, heteroatom-rich surface functionalized blue fluorescent carbon dots (CDs) were synthesized for high-throughput detection of folic acid (vitamin B9). The highly stable CDs could particularly detect vitamin B9 in the presence of 35 analytes, even up to 40 nM of the vitamin. The versatile CDs were found to have a high affinity for folic acid in wastewater, folic acid tablets, and food samples enriched with folic acid.
View Article and Find Full Text PDFFor the realization of truly reconfigurable metasurface technologies, dynamic spatial tuning of the metasurface resonance is required. Here we report the use of organic photoswitches as a means for the light-induced spatial tuning of metasurface resonances. Coating of a dielectric metasurface, hosting high-quality-factor resonances, with a spiropyran (SPA)-containing polymer enabled dynamic resonance tuning up to 4 times the resonance full-width at half-maximum with arbitrary spatial precision.
View Article and Find Full Text PDFEvidence suggests that beta-amyloid (Aβ)-induced phosphorylation/aggregation of tau protein plays a critical role in the degeneration of neurons and development of Alzheimer's disease (AD), the most common cause of dementia affecting the elderly population. Many studies have pursued a variety of small molecules, including nanoparticles conjugated with drugs to interfere with Aβ and/or tau aggregation/toxicity as an effective strategy for AD treatment. We reported earlier that FDA approved PLGA nanoparticles without any drug can attenuate Aβ aggregation/toxicity in cellular/animal models of AD.
View Article and Find Full Text PDFThe carrier-envelope phase (CEP) is an important property of few-cycle laser pulses, allowing for light field control of electronic processes during laser-matter interactions. Thus, the measurement and control of CEP is essential for applications of few-cycle lasers. Currently, there is no robust method for measuring the non-trivial spatial CEP distribution of few-cycle laser pulses.
View Article and Find Full Text PDFSecond-harmonic generation (SHG) is a second-order nonlinear optical process that is not allowed in media with inversion symmetry. However, due to the broken symmetry at the surface, surface SHG still occurs, but is generally weak. We experimentally investigate the surface SHG in periodic stacks of alternating, subwavelength dielectric layers, which have a large number of surfaces, thus enhancing surface SHG considerably.
View Article and Find Full Text PDFComplex 3D-shaped optics are difficult to coat with conventional technologies. In this research, large top-open optical glass cubes with a 100 mm side length were functionalized to simulate large dome-shaped optics. Antireflection coatings for the visible range (420-670 nm) and for a single wavelength (550 nm) were applied by atomic layer deposition simultaneously on two and six demonstrators, respectively.
View Article and Find Full Text PDFACS Appl Mater Interfaces
May 2023
Heterostructures increasingly attracted attention over the past several years to enable various optoelectronic and photonic applications. In this work, atomically thin interfaces of Ir/AlO heterostructures compatible with micro-optoelectronic technologies are reported. Their structural and optical properties were determined by spectroscopic and microscopic techniques (XRR, XPS, HRTEM, spectroscopic ellipsometry, and UV/vis/NIR spectrophotometry).
View Article and Find Full Text PDFWe report for the first time the direct growth of molybdenum disulfide (MoS) monolayers on nanostructured silicon-on-insulator waveguides. Our results indicate the possibility of utilizing the Chemical Vapour Deposition (CVD) on nanostructured photonic devices in a scalable process. Direct growth of 2D material on nanostructures rectifies many drawbacks of the transfer-based approaches.
View Article and Find Full Text PDFConversion of β-amyloid (Aβ) peptides from soluble random-coil to aggregated protein enriched with β-sheet-rich intermediates has been suggested to play a role in the degeneration of neurons and development of Alzheimer's disease (AD) pathology. Aggregation of Aβ peptide can be prompted by a variety of environmental factors including temperature which can influence disease pathogenesis. Recently, we reported that FDA-approved unconjugated poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles can have beneficial effects in cellular and animal models of AD by targeting different facets of the Aβ axis.
View Article and Find Full Text PDFAtomically thin heterostructures and superlattices are promising candidates for various optoelectronic and photonic applications. Different combinations of AlO/TiO composites are obtained by plasma enhanced atomic layer deposition (PEALD). Their growth, composition, dispersion relation, and optical bandgap are systematically studied by means of UV/VIS spectrophotometry, spectroscopic ellipsometry (SE), x-ray reflectometry (XRR), scanning transmission electron microscopy(STEM) and x-ray photoelectron spectroscopy (XPS).
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