Abstract
Recently the area of bioimaging has benefited from new types of image enhancing agents such as quantum dots, carbon nanotubes and other nanoparticles. Cellular or even molecular level resolution has been achieved with different techniques during these last years (i.a. Fluorescence microscopy, PET/CT scan, AFM). Optical Coherence Tomography (OCT) as an imaging technique should also profit from newly developed probes. In this work we explored the tunable properties of different types of nanoparticles as contrast enhancers in OCT applications. We mainly studied the development and characteristics of metallic nanoparticles with tunable properties: gold nanoshells made of a silica core coated with a gold shell. Nanoshell and nanoparticles processing techniques are discussed, as well as their optimization for designing particles with specific absorption and scattering characteristics, and its use in OCT imaging.

Abstract
In this letter, a temperature sensor using a fiber loop mirror containing a piece of highly birefringent erbium doped fiber is presented. A Hi-Bi PANDA erbium-doped silica fiber was used and compared with the conventional Hi-Bi PANDA fiber. Different results for strain and temperature sensitivity were obtained. The temperature coefficient sensitivity was -2.22 nm/degrees C and significantly higher when compared with others conventional Hi-Bi fibers. Strain experiments were also performed. (C) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3152-3154 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23907

Abstract
This work presents a method to tune the sensitivity of the sensor in a highly birefringent erbium-doped fiber loop mirror (FLM) when it is pumped. This concept was used for simultaneous measurement of strain and temperature. The FLM is sequentially pumped and unpumped by a high pump laser at 980 nm to change the erbium-doped fiber properties. The sensing head changes its sensitivity when subjected to strain and/or temperature variations due to thermal effects originated by the pump laser.

Abstract
An optical current sensor based on a metal coated Hi-Bi fiber loop mirror is reported. This current sensor quantifies the current through the measurement of the temperature which varies accordingly with the magnitude of the electrical current. The temperature change is analyzed through the variation of the wavelength shift of a fringe minimum of a Hi-Bi fiber loop mirror. The minimum current detection was found to be approximately 10 A. (c) 2008 Wiley Periodicals, Inc.

Abstract
We present a potential sensor head for the simultaneous measurement of temperature and strain based on the concatenation of two long-period fiber gratings arc-induced in different fibers. Despite being the temperature and strain sensitivities of the individual gratings well defined, we demonstrate that the sensor cannot perform the simultaneous measurement of those physical parameters. This fact, results from the uncertainty in finding the determinant of the inverse matrix. (C) 2008 Wiley Periodicals, Inc.

Abstract
We present results on the measurements of polarization dependent loss (PDL) of mechanically induced long-period fibre gratings. It is shown that a proper choice of the fabrication parameters leads to a considerable reduction of PDL values.