An optical-based sensor for detecting the presence or amount of an analyte using both indicator and reference channels. The sensor has a sensor body with a source of radiation embedded therein. Radiation emitted by the source interacts with indicator membrane indicator molecules proximate the surface of the body. At least one optical characteristic of these indicator molecules varies with analyte concentration. For example, the level of fluorescence of fluorescent indicator molecules or the amount of light absorbed by light-absorbing indicator molecules can vary as a function of analyte concentration. In addition, radiation emitted by the source also interacts with reference membrane indicator molecules proximate the surface of the body. Radiation (e.g., light) emitted or reflected by these indicator molecules enters and is internally reflected in the sensor body. Photosensitive elements within the sensor body generate both indicator channel and reference channel signals to provide an accurate indication of the concentration of the analyte. Preferred embodiments are totally self-contained and are sized and shaped for use in vivo in a human being. Such embodiments preferably include a power source, e.g. an inductor, which powers the source of radiation using external means, as well as a transmitter, e.g. an inductor, to transmit to external pickup means the signal representing the level of analyte.

Optical-based sensing devices

Ferromagnetism usually only occurs in materials containing elements that form covalent 3d and 4f bonds. Its occurrence in pure carbon is therefore surprising, even controversial. A systematic magnetic force microscope study indicates that ferromagnetism in graphite is the result of localized spins that arise at grain boundaries.

Room-temperature ferromagnetism in graphite driven by two-dimensional networks of point defects

IR spectroscopy in catalysis

/pdf/room-temperature-ferromagnetism-in-graphite-driven-by-two-36ae7e3kaz.pdf

Chromophores in porous silicas and minerals: preparation and optical properties

Resonant optical second harmonic generation from vicinal Si(001) and Si(001)-Sb around 3.3 eV is shown to be dominated by electronic states associated with reconstruction of the surface step. The mirror plane perpendicular to the step edge, which is present in the macroscopic surface and in the bulk and terrace crystallographic structures, is absent in the resonant second harmonic response from vicinal Si(001)-( $1\ifmmode\times\else\texttimes\fi{}1$)-Sb.

Resonant optical second harmonic generation at the steps of vicinal Si(001).

Nucleation and evolution of the Au-induced 5 x 2 structure on vicinal Si(111).

Angle-resolved photoemission from an unusual quasi-one-dimensional metallic system: a single domain Au-induced 5 × 2 reconstruction of Si(111)

Two evanescent wave fiber optic sensors for oxygen are reported: one intensity based and the other based on phase fluorimetry. Both sensors employ the quenching by oxygen of the fluorescence from a ruthenium complex trapped in the cagelike structure of a sol-gel-derived porous film on a declad section of multimode optical fiber. The sensors exhibit excellent performance using excitation from new high brightness blue LEDs and establish the viability of low-cost portable sensor devices based on the 501-gel process.

Light-emitting-diode-based oxygen sensing using evanescent wave excitation of a dye-doped sol-gel coating

Si(111) surfaces misoriented by 4 degrees towards (112) have been studied by scanning tunnelling microscopy. Topographs of surfaces, produced by annealing, followed by rapid quenching, reveal a temperature-dependent transition from a structure consisting of wide irregular terraces separated by small irregular clusters of double steps to a single highly ordered phase of narrow, evenly spaced terraces separated by single monatomic steps. The quenched-in phases are stable at room temperature.

http://iopscience.iop.org/article/10.1088/0268-1242/8/4/003/pdf

J.D. O'Mahony

Papers

Resonant optical second harmonic generation at the steps of vicinal Si(001).

Nucleation and evolution of the Au-induced 5 x 2 structure on vicinal Si(111).

Angle-resolved photoemission from an unusual quasi-one-dimensional metallic system: a single domain Au-induced 5 × 2 reconstruction of Si(111)

Light-emitting-diode-based oxygen sensing using evanescent wave excitation of a dye-doped sol-gel coating

Control of terrace width and atomic step distribution on vicinal Si(111) surfaces by thermal processing