Thiolated gamma-cyclodextrin-polymer-functionalized CeFeO magnetic nanocomposite as an intrinsic nanocatalyst for the selective and ultrasensitive colorimetric detection of triacetone triperoxide.

Explosives are powerful destructive weapons used by criminals and terrorists across the globe and their use within military installation sites poses serious environmental health problems. Existing colorimetric sensors for triacetone triperoxide (TATP) relies on detecting its hydrolysed HO form. However, such detection strategy limits the practicability for on-site TATP sensing.

Controlled metallization of ion-exchanged glasses by thermal poling.

We present studies of the formation of silver nanoparticles (NPs) in silver-sodium ion-exchanged glasses by a combination of thermal poling and nanosecond pulsed laser irradiation at 355 nm. In poling, silver ions drift deeper into the glass and become separated from the glass surface by a poled layer depleted in cations. Performed measurements have indicated poling-induced broadening of silver ions depth distribution.

Rapid and highly selective colorimetric detection of nitrite based on the catalytic-enhanced reaction of mimetic Au nanoparticle-CeO nanoparticle-graphene oxide hybrid nanozyme.

The International Agency for Research cancer (IARC) has classified nitrite in Group 2A of probable carcinogens to human. Herein, we report on the rapid and selective colorimetric detection of nitrite using a chemically modified gold nanoparticle (AuNP)-cerium oxide (CeO) NP-anchored graphene oxide (GO) hybrid nanozyme in a catalytic colorimetric assay where nitrite acts as the main oxidant/target analyte and 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate. CeO NPs and GO were synthesized separately and incorporated in-situ, in a synthetic solution involving the chemical reduction of Au salt to AuNPs.

Biomimetic graphene oxide-cationic multi-shaped gold nanoparticle-hemin hybrid nanozyme: Tuning enhanced catalytic activity for the rapid colorimetric apta-biosensing of amphetamine-type stimulants.

Amphetamine-type stimulants are a class of illicit drug that constitutes a worldwide problem to which intelligence agencies, first responders and law enforcement are tasked with identifying them in unknown samples. We report on the development of a graphene oxide (GO)-cationic multi-shaped gold nanoparticle (AuNP)-hemin hybrid nanozyme as a new biomimetic catalytic-induced aptamer-based colorimetric biosensor platform for amphetamine (AMP) and methamphetamine (MAMP). GO was electrostatically bonded to cationic multi-shaped cetyltrimethylammonium bromide (CTAB)-AuNPs to form a GO-CTAB-AuNP hybrid nanozyme exhibiting enhanced catalytic activity in the presence of hemin.

Aptamer-based cocaine assay using a nanohybrid composed of ZnS/AgSe quantum dots, graphene oxide and gold nanoparticles as a fluorescent probe.

Authors report on a new fluoro-graphene-plasmonic nanohybrid aptamer-based fluorescent nanoprobe for cocaine. To construct the nanoprobe, newly synthesized glutathione-capped ZnS/AgSe quantum dots (QDs) were first conjugated to graphene oxide (GO) to form a QD-GO nanocomposite. The binding interaction resulted in a fluorescence turn-ON.

Radially and azimuthally polarized laser induced shape transformation of embedded metallic nanoparticles in glass.

Radially and azimuthally polarized picosecond (~10 ps) pulsed laser irradiation at 532 nm wavelength led to the permanent reshaping of spherical silver nanoparticles (~30 - 40 nm in diameter) embedded in a thin layer of soda-lime glass. The observed peculiar shape modifications consist of a number of different orientations of nano-ellipsoids in the cross-section of each written line by laser. A Second Harmonic Generation cross-sectional scan method from silver nanoparticles in transmission geometry was adopted for characterization of the samples after laser modification.

On the frequency-doubled conically-refracted Gaussian beam.

A Potassium Titanyl Phosphate (KTP) crystal has been used in conjunction with a 10-ps pulsed laser to produce a frequency-doubled conically-refracted Gaussian beam. The 'free' and 'forced' beams that make up the scheme for nonlinear conical refraction were readily observable in non-phase-matched conditions. The dependency of the frequency-doubled beam patterns on the incident beam polarization, which until now has remained unexplored, was examined in detail.

Azimuthally and radially polarized light in conical diffraction.

Azimuthal and radial polarization states of light are used to produce conical diffraction (CD) from a KGd(WO4)2 crystal. The patterns produced in the ring plane in each case display marked differences than those seen when linearly polarized incident light is used, with the production of a splitting of the CD ring into two concentric rings of equal intensity. The free space evolution for each type of polarization state is also experimentally recorded and investigated.

Coherent control of plasmonic nanoantennas using optical eigenmodes.

The last decade has seen subwavelength focusing of the electromagnetic field in the proximity of nanoplasmonic structures with various designs. However, a shared issue is the spatial confinement of the field, which is mostly inflexible and limited to fixed locations determined by the geometry of the nanostructures, which hampers many applications. Here, we coherently address numerically and experimentally single and multiple plasmonic nanostructures chosen from a given array, resorting to the principle of optical eigenmodes.

P-i-n junction quantum dot saturable absorber mirror: electrical control of ultrafast dynamics.

We report on nonlinear optical properties of a p-i-n junction quantum dot saturable absorber based on InGaAs/GaAs. Absorption recovery dynamics and nonlinear reflectivity are investigated for different reverse bias and pump power conditions. A decrease in absorption recovery time of nearly two orders of magnitude is demonstrated by applying a voltage between 0 and -20 V.

Diode-pumped Yb,Er:glass laser passively Q switched with a V3+:YAG crystal.

Saturable-absorber Q switching of a diode-pumped erbium-doped glass laser at 1.54 microm with a V:YAG crystal has been demonstrated. An average output power of 30 mW with Q-switching efficiency of 37% and pulse duration of 350 ns have been obtained.