Resonance radiation improvement

UV/visible/NlR semiconductor diode lasers (DLs) as sources of tunable narrowband resonance radiation have been discussed in Section 22.2.2. The practical and technical advantages of visible/ NIR DLs are ease of operation, small size, room-temperature operation, and low price. In comparison with hollow cathode lamps (HCLs), they have such advantages as high spectral power, spatial coherence, and tunability. Owing to these features, detection limits, dynamic range, and selectivity of analysis are all significantly improved. 

Fig. 11.2. The total photoelectron yield spectrum of lanthanum in the solid phase, as obtained by synchrotron radiation spectroscopy in the neighbourhood of the 3d threshold. Curve (a) shows the experimental data points with the sum of two Lorentzian profiles fitted to them. Curve (b) shows the same data points for the higher of the two resonances, with a Fano profile fitted to it. The improvement in the fit is clear evidence for a slight asymmetry due to autoionisation (after R.C. Karnatak et al. [599]).

The microstructure observation of the sintered ceramics surface was performed by means of scanning electron microscopy (SEM, JEOL JSM 6400, Japan). The crystalline phase of sintered ceramics was identified by X-ray diflfaction (XRD, RIGAKU D/max 2.B) with CuKa radiation (X=l. 541SA at 40 kV and 30 mA) and scanned from 20° to 70° with scanning speed of 4°/min. The bulk densities of the sintered pellets were measured by the Archimedes method. The dielectric constant ( ,) and the quality factor values (Qxf) at microwave frequencies were measured using the Hakki-Coleman dielectric resonator method which had been modified and improved by Courtney The dielectric resonator was positioned between two brass plates. Microwave... 

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