Dark-field microscopy studies of single silicon nanoparticles fabricated by e-beam evaporation technique: effect of thermal annealing, polarization of light and deposition parameters.

Herein, we report the dark-field microscopy studies on single silicon nanoparticles (SiNPs) fabricated using different deposition parameters in the electron beam evaporation technique. The morphology of the fabricated SiNPs is studied using theor the first time, the effect of thermal annealing and deposition parameters (i.e.

Enhancement of Raman signal of monolayer graphene films using a single optical microsphere-assisted Raman microscopic technique.

For the first time, we report the enhancement of the Raman scattering signal of monolayer graphene films (MGFs) on Cu foils using a single optical microsphere-assisted Raman microscopic (SOMRM) technique. Initially, the Raman scattering spectra of MGF on Cu foil are recorded using the conventional Raman microscopic (CRM) technique, where the excitation laser is directly focused on the MGFs with the help of a different microscopic objective lens. The obtained spectra are observed to consist of only the low-intensity G and 2D bands but not the D band, known as the disorder or defect band.

Characteristic parameters of photonic nanojets of single dielectric microspheres illuminated by focused broadband radiation.

Herein, we report the theoretical investigation on the photonic nanojets (PNJs) of single dielectric microspheres illuminated by focused broadband radiation (polychromatic light) from a Halogen lamp, supercontinuum source, light-emitting diode, and Hg arc lamp. The role of incident beam waist, refractive index of the surrounding medium, and radius of the microsphere on the characteristic parameters such as the electric field intensity enhancement, effective width, and length of the PNJ is studied. Interestingly, the characteristic parameters of the PNJs of solid microspheres obtained for the above-mentioned broadband radiation sources are found close to those observed for the focused monochromatic radiation of wavelengths which are near to the central wavelengths of the sources.

Indium nanoparticle-based surface enhanced fluorescence from deep ultraviolet to near-infrared: A theoretical study.

Herein, for the first time, we report a theoretical investigation on Indium nanoparticle-based surface enhanced fluorescence (SEF) from deep ultraviolet (UV) to near-infrared (NIR). In the beginning, the far- and near-field plasmonic properties of the Indium nanospheres of different sizes are studied to extract the wavelengths of lower and higher-order localized surface plasmon modes and the corresponding local electric field enhancement (EFE) values. Later, the dependence of the SEF enhancement with the separation between the fluorophore and nanoparticle (d), fluorescence, and excitation wavelengths is studied systematically.

Study of surface enhanced Raman scattering of IR-780 Iodide molecules using Au-Ag bimetallic nanostructures with blunt and sharp sprouts.

Au-Ag bimetallic nanostructures with blunt and sharp sprouts are synthesized using a high yield one-step synthesis process. For the first time, these nanostructures are obtained at different growth times in the same synthesis process. The synthesized nanostructures are characterized using a field emission-scanning electron microscope, transmission electron microscope, energy dispersive X-ray analyzer, and UV-Visible spectrometer.

Numerical investigations on photonic nanojet mediated surface enhanced Raman scattering and fluorescence techniques.

Finite element method simulations have been carried out on the photonic nanojet (PNJ) mediated surface enhanced Raman scattering (SERS) technique for the first time, and this technique has been found to provide (i) better Raman scattering enhancement of single molecules and (ii) a long working distance between the microscopic objective lens and sample, as compared with the conventional SERS technique. A PNJ mediated surface enhanced fluorescence (SEF) technique has been proposed to enhance the fluorescence of single molecules using the combination of localized surface plasmons inside nanostructures and the PNJ of a dielectric microsphere (MS), and this technique is numerically proved to be efficient as compared with a conventional SEF technique. Moreover, the generation of a PNJ from single lollipop shaped microstructures and its applications in the above mentioned techniques have been reported.

Label-free detection of single protein using a nanoplasmonic-photonic hybrid microcavity.

Recently we reported the detection and sizing of the smallest RNA virus MS2 with a mass of 6 ag from the resonance frequency shift of a whispering gallery mode-nanoshell hybrid resonator (WGM-h) upon adsorption on the nanoshell and anticipated that single protein above 0.4 ag should be detectable but with considerably smaller signals. Here, we report the detection of single thyroid cancer marker (Thyroglobulin, Tg) and bovine serum albumin (BSA) proteins with masses of only 1 ag and 0.

Periodic plasmonic enhancing epitopes on a whispering gallery mode biosensor.

We propose the attachment of a periodic array of gold nanoparticles (epitopes) to the equator of a Whispering Gallery Mode Biosensor for the purpose of plasmonically enhancing nanoparticle sensing in a self-referencing manner while increasing the capture rate of analyte to antibodies attached to these plasmonic epitopes. Our approach can be applied to a variety of whispering gallery mode resonators from silicon/silica rings and disks to capillaries. The interpretation of the signals is particularly simple since the optical phase difference between the epitopes is designed to be an integer multiple of ?, allowing the wavelength shift from each binding event to add independently.