Spectral coverage

And a rotation of the emitter-receiver transducer around the "object" (or a rotation of the object) gives a annulus of center O and radii [Km, Km] [2]. The situation is identical to that of X-ray tomography (slice-by-slice spectral coverage), but with a band-pass spectral filter instead of a low-pass spectral filter. ... 

Light sources can either be broadband, such as a Globar, a Nemst glower, an incandescent wire or mercury arc lamp or they can be tunable, such as a laser or optical parametric oscillator (OPO). In the fomier case, a monocln-omator is needed to achieve spectral resolution. In the case of a tunable light source, the spectral resolution is detemiined by the linewidth of the source itself In either case, the spectral coverage of the light source imposes limits on the vibrational frequencies that can be measured. Of course, limitations on the dispersing element and detector also affect the overall spectral response of the spectrometer. 

If we wish to include spectral coverage and extended sources into our considerations, we need to review the theory of diffraction and to introduce some concepts of coherence. 

Bos, F. (1981) Optimization of spectral coverage in an eight-cell oscillator-amplifier dye laser pumped at 308nm. Appl. Opt. 20, 3553. 

Sensor Agency Satellite Operating Dates Resolution (m) Number of Bands Spectral Coverage (nm) Ref. 

There are numerous excitation sources available for LIF instruments. A xenon arc lamp is the most common light source within commercial LIF analyzers. While they offer uniform broad spectral coverage across the UV-vis range and sufficient uniform power output, they are low precision sources and do not offer sufficient real-time or dynamic optical power control. The white output also necessitates an excitation... 

Dye lasers can operate from around 250-1285 mn and the individual dye components can be fine tuned to operate in the range of 30-50 nm. As detailed in section 3.5.1, there are several classes of fluorescent dyes that can be used in dye lasers the approximate spectral coverage of these are shown in Table 3.8. 

Such time-dependent studies can also be carried out using an FTIR to obtain full, or at least broad, spectral coverage as a function of time. 153 In this case it is imperative that the time-dependent process to be studied has a cyclic character or be virtually indefinitely repeatable (e.g., T-jump or reversible photo excitation). The simplest way of doing such... 

This is considerably different from the recombination reaction with, for example, typical ruthenium dyes. This slow re-reduction of the dyad is explained by the low redox potential of the osmium center, the value of 0.66 V (vs. SCE) observed, points to a small driving force for the redox process. This observation is important for the design of dyes for solar cell applications. Osmium compounds have very attractive absorption features, which cover a large part of the solar spectrum. However, their much less positive metal-based oxidation potentials will result in a less effective re-reduction of the dyes based on that metal and this will seriously affect the efficiency of solar cells. In addition, for many ruthenium-based dyes, the presence of low energy absorptions, desirable for spectral coverage, is often connected with low metal-based redox potentials. This intrinsically hinders the search for dyes which have a more complete coverage of the solar spectrum. Since electronic and electrochemical properties are very much related, a lowering of the LUMO-HOMO distance also leads to a less positive oxidation potential. 

Fa (AA)" AA, spectral coverage of a single resolution element (during time t)... 

Absorption and Fluorescence Instrumentation. Absorption spectra were obtained using a Princeton Applied Research Corp. (PARC) Model 1208 polychromator, a Perkin-Elmer 8 yL absorption flow-cell and a 50 watt deuterium light source. Fluorescence spectra were obtained using a Farrand Mark 1 Spectrofluorometer (previously described (13)) and either a 10 iiL Farrand micro flow-cell, or a Precision Cells, Inc. (Model No. 8830) 20 yL flow-cell. A PARC Model 1254 SIT detector, having a UV scintillator, was mounted on both the absorption polychromator and fluorescence spectrofluorometer. Spectral coverage in the absorption and fluorescence modes was 60 and 115 nm, respectively. All absorption and fluorescence spectra were obtained in one second, i.e., 32 scans of the SIT target. 

The barriers to this approach have been technical in nature. Mode-locked Nd glass lasers remain a common light source for picosecond spectroscopic studies, but they suffer from poor reproducibility and very low repetition rates. These features combine to make wavelength scanning techniques unsuitable with such lasers. The alternative approach is to employ multichannel optical detection and thereby obtain full spectral coverage with each laser shot. It is also necessary to eliminate the effects of shot-to-shot variations of the laser output. 

In some instances, the design of the data acquisition system may be driven by the requirements of a specific application. In ICP-MS, for example, the masses of the elemental isotopes are well known, so only those masses need to be investigated. In such a situation, an attractive technique is the use of a number of single-channel devices, such as boxcar integrators [38], each of which is responsible for continually monitoring a specific mass of interest. At the expense of complete mass spectral coverage, a simple, inexpensive system that generates relatively small amounts of data with real-time temporal resolution can be utilized. 

Cao X, Shah RD, Dukor RK et al (2004) Extension of Fourier transform vibrational circular dichroism into the near-infrared region continuous spectral coverage from 800 to 10 000 cm (—1). Appl Spectrosc 58 1057-1064... 

FIG. 7. Identification of four glycosylation sites of the isolated MUC4 derivative by ECD-MS/MS analysis. (A) Results of the spectral matching analysis using 30 possible structures. (B) the top four structures predicted by in silico calculation and the spectral coverage (%) when compared with die real experimental spectrum. This figure is adapted from ref. 77. (Continued)... 

---