Computational modelling of a graphene Fresnel lens on different substrates

In this work we studied tunable lensing effects of graphene Fresnel lens on different substrates with incident light of 850 nm and 1550 nm wavelengths.</p

Raman imaging through multimode sapphire fiber

We report on a sapphire fiber Raman imaging probe's use for challenging applications where access is severely restricted. Small-dimension Raman probes have been developed previously for various clinical applications because they show great capability for diagnosing disease states in bodily fluids, cells, and tissues. However, applications of these sub-millimeter diameter Raman probes were constrained by two factors: first, it is difficult to incorporate filters and focusing optics at such small scale; second, the weak Raman signal is often obscured by strong background noise from the fiber probe material, especially the most commonly used silica, which has a strong broad background noise in low wavenumbers (<500-1700 cm(-1)). Here, we demonstrate the thinnest-known imaging Raman probe with a 60 mu m diameter Sapphire multimode fiber in which both excitation and signal collection pass through. This probe takes advantage of the low fluorescence and narrow Raman peaks of Sapphire, its inherent high temperature and corrosion resistance, and large numerical aperture (NA). Raman images of Polystyrene beads, carbon nanotubes, and CaSO(4 )agglomerations are obtained with a spatial resolution of 1 tun and a field of view of 30 mu m. Our imaging results show that single polystyrene bead (similar to 15 mu m diameter) can be differentiated from a mixture with CaSO(4 )agglomerations. which has a close Raman shift. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Carbon Nanotube Array Based Binary Gabor Zone Plate Lenses

Diffractive zone plates have a wide range of applications from focusing x-ray to extreme UV radiation. The Gabor zone plate, which suppresses the higher-order foci to a pair of conjugate foci, is an attractive alternative to the conventional Fresnel zone plate. In this work, we developed a novel type of Beynon Gabor zone plate based on perfectly absorbing carbon nanotube forest. Lensing performances of 0, 8 and 20 sector Gabor zone plates were experimentally analyzed. Numerical investigations of Beynon Gabor zone plate configurations were in agreement with the experimental results. A high-contrast focal spot having 487 times higher intensity than the average background was obtained

Laser directed writing of flat lenses on buckypaper

Laser directed patterning of carbon nanotubes-based buckypaper for producing a diffractive optical device is presented here.</p

Optical scattering from graphene foam for oil imaging/sensing

This work studied a new way of sensing oil leaks using graphene foam through an optical imaging and light scattering method.</p

Line-Monitoring, Hyperspectral Fluorescence Setup for Simultaneous Multi-Analyte Biosensing

Conventional fluorescence scanners utilize multiple filters to distinguish different fluorescent labels, and problems arise because of this filter-based mechanism. In this work we propose a line-monitoring, hyperspectral fluorescence technique which is designed and optimized for applications in multi-channel microfluidic systems. In contrast to the filter-based mechanism, which only records fluorescent intensities, the hyperspectral technique records the full spectrum for every point on the sample plane. Multivariate data exploitation is then applied to spectra analysis to determine ratios of different fluorescent labels and eliminate unwanted artifacts. This sensor is designed to monitor multiple fluidic channels simultaneously, providing the potential for multi-analyte biosensing. The detection sensitivity is approximately 0.81 fluors/μm2, and this sensor is proved to act with a good homogeneity. Finally, a model experiment of detecting short oligonucleotides has demonstrated the biomedical application of this hyperspectral fluorescence biosensor

Nanophotonic devices based on graphene and carbon nanotubes

The research presented in the thesis includes the modelling and characterization of the novel devices based on graphene and carbon nanotube (CNT)-based buckypaper. The devices have great potential to be used in applications such as photovoltaics, optical communications/imaging and sensors for oil and gas industry. Graphene is a promising material with excellent optical and electrical properties. Research was carried out in utilizing graphene for photonic and plasmonic devices, including ultra-thin flat lens, plasmonic lens, and oil sensor. Buckypaper extends the applications of CNTs’ excellent properties from nanoscale to microscale. This opportunity was explored in the development of ultra-thin flat lens

The complete chloroplast genome of Rungia pectinata (Acanthaceae)

Rungia pectinata is an important traditional Chinese herbal medicine from the family Acanthaceae. The complete chloroplast genome (cp genome) of the genus Rungia was sequenced for the first time. The cp genome of R. pectinata was 149,627 bp in length. It was consisted of a large single copy (LSC) region (81,976 bp) and a small single copy (SSC) region (16,626 bp), which were separated by two inverted repeats (IRs, 25,511 bp). This plastome contained 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. The overall GC content was 38.0%. Phylogenetic analysis of nine species in Acanthaceae was also conducted. This newly sequenced cp genome will be useful to further evolutionary studies, phylogenetic studies, and pharmacognostic identification in the genus Rungia