Multi-wavelength Spectrometer Research Articles

The generation of multiple electric and magnetic Fano resonances in the prefect ring-triple arcs ring nanostructure

The electromagnetic field enhancement, multiple electric and magnetic Fano resonances in perfect ring-triple arcs ring (PR-TAR) nanostructure are studied by using finite element method. In this nanostructure, electric and magnetic Fano resonances can be promoted as a result of the coupling between dark modes of the perfect ring (PR) and bright modes of the triple arcs ring (TAR). New multiple electric and magnetic Fano resonances are obtained by changing the central angle or the thickness of the up arc. Multiple new resonance modes can be generated by offsetting the center of the TAR. According to the calculation results, the electric and magnetic fields are both enhanced greatly. The highest electric and magnetic field enhancements reached 409 and 48.7, respectively. These characteristics of the PR-TAR nanostructure have potential applications on the propagation of low-loss plasmons, surface enhanced plasmon spectroscopy, multi-wavelength spectrometer and multi-control Fano switch.

Correlation between the Gas Temperature and the Atomization Behavior of Analyte Elements in Flame Atomic Absorption Spectrometry Estimated with a Continuum-light-source Spectrometer System

In flame atomic absorption spectrometry (FAAS), the gas temperature for two types of the gas compositions, which was estimated based on a two-line method by using a simultaneous multi-wavelength spectrometer, on which a line pair of ruthenium, Ru I 372.692 nm and Ru I 372.803 nm having different excitation energies, was measured at the same time. Also using the spectrometer system, the absorption signals of both iron and ruthenium, whose oxides had different thermodynamic properties: the latter oxide was decomposed much more easily than the former one, were investigated with a nitrous oxide - acetylene flame, in comparison with an air - acetylene flame. The fuel/oxidant ratio of both the flames as well as the height of the optical path was varied as an experimental parameter. The atomization behavior of iron and ruthenium, which could be deduced from a variation in their absorption signals, was considered to be dependent not only on the gas temperature but on reducing atmosphere of the flame gas, which might be attributed to reducing radicals in a fuel-excess flame consisting of nitrous oxide. In the nitrous oxide - acetylene flame, a broader optical path having a constant and higher temperature was obtained, thus contributing to formation of analyte atoms with a stable atomization efficiency and eventually to better precision in the analytical result in FAAS.

The first observation and data reduction of the Multi-wavelength Spectrometer on the New Vacuum Solar Telescope

The Multi-wavelength Spectrometer is a medium-dispersion (R ∼ 130000) grating spectrometer installed on the New Vacuum Solar Telescope at the Fuxian Solar Observatory, Yunnan Astronomical Observatory, Chinese Academy of Sciences. It is designed to accurately observe the velocity and magnetic fields of the Sun. The present configuration of this spectrometer allows us to simultaneously observe three different solar spectral lines. This work is dedicated to showing the first observations carried out in both the Hα and Ca II 8542 Å lines. We give a detailed description of the data reduction process, focusing on the retrieval of a flat field from the high-resolution spectral data. Two different methods are also performed and compared to eliminate the residual fringe in the reduced data. The real spectral resolution and instrumental profile are analyzed based on the final results, which indicate that this spectrometer presently satisfies the expected performance and it is ready for further scientific observations.

Controlled Etching of III-V Materials with Optical Emission Interferometry (OEI)

For plasma etching processes, Optical Emission Interferometry (OEI) combines the advantages of Optical Emission Spectroscopy (OES) and laser interferometry. Radiation emitted by the plasma is reflected from the substrate surface and monitored using a multi-wavelength spectrometer. Analysis of the OEI signal can provide endpoint data, as well as etch rate and etch depth information for both single and multi-component materials. Examples of these applications are described.

High-Resolution In Situ Analysis of Nitrate and Phosphate in the Oligotrophic Ocean

Accurate, high-resolution profiles of nitrate and phosphate distributions in the open ocean are difficult to obtain using conventional techniques. Concentrations typically range from low nanomolar levels in the stratified euphotic zone to micromolar levels below the nutricline. With multiple pumps, a heating cartridge, a long-path-length cell, and a multiwavelength spectrometer, the reconfigured Spectrophotometric Elemental Analysis System (SEAS) provides the capability to fully ascertain the distributions of nitrate and phosphate in the upper 200 m of the oligotrophic ocean. By utilizing a 15 cm path length and multiple wavelength spectrophotometry, SEAS can detect nitrate concentrations from 2 nM to 20 microM and, with a 50 cm path length, can accurately measure phosphate concentrations from 1 nM to 1 microM. SEAS is capable of collecting auxiliary data from up to four separate instruments, including a CTD, a fluorometer, a PAR sensor, and a second SEAS instrument. Sampling frequency depends on peripheral instrument selection and ranges from 0.4 to 0.75 Hz.

The oxygen status algorithm: A computer program for calculating and displaying pH and blood gas data

Input parameters for the program are the arterial pH, pCO2, and pO2 (measured by a blood gas analyzer), oxygen saturation, carboxy-, met-, and total hemoglobin (measured by a multi-wavelength spectrometer), supplemented by patient age, sex, temperature, inspired oxygen fraction, fraction of fetal hemoglobin, and ambient pressure. Output parameters are the inspired and alveolar oxygen partial pressures, pH,pCO2 and pO2 referring to the actual patient temperature, estimated shunt fraction, half-saturation tension, estimated 2,3-diphosphoglycerate concentration, oxygen content and oxygen capacity, extracellular base excess, and plasma bicarbonate concentration. Three parameters related to the blood oxygen availability are calculated: the oxygen extraction tension, concentration of extractable oxygen, and oxygen compensation factor. Calculations of the 'reverse' type may also be performed so that the effect of therapeutic measures on the oxygen status or the acid-base status can be predicted. The user may choose among several different units of measurement and two different conventions for symbols. The results are presented in a data display screen comprising all quantities together with age, sex, and temperature adjusted reference values. The program generates a 'laboratory diagnosis' of the oxygen status and the acid-base status and three graphs illustrating the oxygen status and the acid-base status of the patient: the oxygen graph, the acid-base chart and the blood gas map. A printed summary in one A4 page including a graphical display can be produced with an Epson or HP Laser compatible printer. The program is primarily intended for routine laboratories with a blood gas analyzer combined with a multi-wavelength spectrometer. Calculating the derived quantities may enhance the usefulness of the analyzers and improve patient care. The program may also be used as a teaching aid in acid-base and respiratory physiology. The program requires an IBM PC, XT, AT or similar compatible computer running under DOS version 2.11 or later. A VGA color monitor is preferred, but the program also supports EGA, CGA, and Hercules monitors. The program will be freely available at the cost of a discette and mailing expenses by courtesy of Radiometer Medical A/S, Emdrupvej 72, DK-2400 Copenhagen NV, Denmark (valid through 1991). A simplified algorithm for a programmable pocket calculator avoiding iterative calculations is given as an Appendix.

Stratospheric nitrogen dioxide concentrations as determined from limb brightness measurements made on June 17, 1983

A multiwavelength spectrometer with limb‐scanning optics was developed to make NO2 measurements in the stratosphere. The instrument observes light scattered by aerosol particles and air molecules and measures the differential attenuation of light at different wavelengths by NO2. A vertical profile of NO2 was determined from the brightness measurements, using the results of a single scattering model. The instrument was flown from Palestine, Texas, and observed the stratosphere from an altitude of 33 km at 32°N, 98°W for a period of several hours on the afternoon of June 17, 1983. The mixing ratio of NO2 was observed to be (3.5±0.8) parts per billion by volume (ppbv) at 28 km, in reasonable agreement with solar occultation measurements. The time rate of change of the NO2 concentration at 28 km is estimated at (0.18±0.06) ppbv per hour at 2200 coordinated universal time (CUT).