Colloidal nanocrystals are nanometer-sized, solution-grown inorganic particles stabilized by a layer of surfactants attached to their surface. The inorganic cores exhibit useful properties controlled by composition as well as size and shape, while the surfactant coating ensures that these structures are easy to fabricate and process. It is this combination of features that makes colloidal nanocrystals attractive and promising building blocks for advanced materials and devices. But their full potential can only be exploited if we achieve exquisite control over their composition, size, shape, crystal structure and surface properties. Here we review what is known about nanocrystal growth and outline strategies for controlling it.

Colloidal nanocrystal synthesis and the organic-inorganic interface

The flat tip of an optical fiber is a unique and unconventional platform for micro and nanotechnologies The small cross-section and large aspect ratio of the fiber provide an inherently light-coupled substrate that is uniquely suited to remote, in vivo and in situ applications However, these same characteristics challenge established fabrication technologies, which are best suited to large planar substrates This review presents a broad overview of strategies for patterning the flat tip of an optical fiber Techniques discussed include self-assembly, numerous lithographies, through-fiber patterning, hybrid techniques, and strategies for mass manufacture, while the diverse applications are discussed in context throughout

The Optical Fiber Tip: An Inherently Light-Coupled Microscopic Platform for Micro- and Nanotechnologies

Silver and silver oxide nanoparticles: Synthesis and characterization by thermal decomposition

Preparation, characterization and cytotoxicity of schizophyllan/silver nanoparticle composite.

Green synthesis of hyaluronan fibers with silver nanoparticles.

We report the high speed scanning submicronic microscopy (SSM) using a low cost polymer microlens integrated at the extremity of an optical fiber. These microlenses are fabricated by a free-radical photopolymerization method. Using a polymer microlens with a radius of curvature of 250 nm, a sub-micrometric gold pattern is imaged experimentally by SSM. Different distances between the tip and the sample are used with a high scanning speed of 200 cm/s. In particular, metallic absorption contrasts are described with an optical spatial resolution of 250 nm at the wavelength of 532 nm. Moreover, finite-difference time-domain (FDTD) simulations concerning the focal lengths of microlenses with different geometries and heights support the experimental data.

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High speed sub-micrometric microscopy using optical polymer microlens

We explore a novel and rapid route for fabricating silver nanoparticles on the distal facet of an optical fiber. The reduction of neutral silver particles relies on the reaction between silver ions and organic free radicals initiated by the photolysis of photoinitiators. A similar approach has been extended to the fabrication of a silver nanoparticle array at the extremity of a fiber bundle. The size and number of silver nanoparticles can be tuned by controlling the laser exposure doses. The results of the synthesis can be envisaged via in situ measurement of their optical transmission rate after the photosynthesis process.

http://iopscience.iop.org/article/10.1088/1612-2011/11/1/016003/pdf

Rapid in situ synthesis of silver nanoparticles on the distal facet of a fiber by laser-induced photo-reduction

Corrigendum: Rapid in situ synthesis of silver nanoparticles on the distal facet of a fiber by laser-induced photo-reduction (2014 Laser Phys. Lett. 11 016003)

The present invention relates to a method for manufacturing end microlenses (101) of individual optical fibres (100) which are part of a bundle or a multi-core fibre, including in particular depositing a drop (2) of a photopolymerisable solution on a first end (10) of the bundle or of said multi-core fibre. The method according to the invention also comprises: adapting the size of said drop (2); applying light (4) centred on a predetermined wavelength onto a second end (20) of the bundle or of said multi-core fibre in order to selectively polymerise said drop (2); rinsing said first end (10) using a methanol solution in order to obtain a network of individual optical fibres (100), each one of which is provided with a microlens (101) at the first end (10) of the multi-core fibre or the bundle, said microlenses (101) being physically separated from one another. The invention additionally relates to a bundle of microlensed fibres obtained by said method, as well as to the use of such a bundle, for example in medical or multiplexed imaging and/or in the coupling of optical fibres.

Method for manufacturing a network of microlenses at the ends of a bundle of optical fibres, related optical fibres and related use

In the present paper, the surface-enhanced Raman spectroscopy (SERS) was used to build the model for the quantitative detection of ethyl paraoxon by the principal component analysis and segmented linear regression (PCA-SLR). Firstly, SERS in 820-1630 cm(-1) of ethyl paraoxon solution were measured and the spectra in 820-1630 cm(-1)(complete range) and 845-875 cm(-1) (characteristic range) of ethyl paraoxon solution were preprocessed by standard normal transformation (SNV), multiplicative scatter correction (MSC), the absolute values of first derivative and the second derivative respectively. Additionally, the number of dimensions of the spectra was reduced by PCA. Finally, the models were established by SLR It was found that the model developed with MSC preprocessed spectroscopy of characteristic range performed best (RMSEP: 0.33) by comparing the predictive accuracy of the different models. The result could meet with the needs in the quantitative detection of ethyl paraoxon.

Xinhua Zeng

Papers

High speed sub-micrometric microscopy using optical polymer microlens

Rapid in situ synthesis of silver nanoparticles on the distal facet of a fiber by laser-induced photo-reduction

Corrigendum: Rapid in situ synthesis of silver nanoparticles on the distal facet of a fiber by laser-induced photo-reduction (2014 Laser Phys. Lett. 11 016003)

Method for manufacturing a network of microlenses at the ends of a bundle of optical fibres, related optical fibres and related use

[Quantitative detection of ethyl paraoxon based on SERS and PCA-SLR].