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[en] Proceeding from the fundamentals a survey is given of the modern methods and experimental possibilities of optical spectroscopy, and of the application to solid state investigations. Contents: receiver, transmission of optical radiation, spectral analysis, polarization, radiation sources, arrangement and measurement. 58 figs., 12 tabs., 177 refs
[en] The generalized impedance spectroscopy is implemented through the detection of perturbations in the electromagnetic impedance of a medium measured at radiofrequencies. The perturbations are caused by the absorption or emission of optical photons. At low powers this offers an extremely high sensitivity spectroscopic technique, which is illustrated here for a two-photon absorption process. In the limit of high powers it becomes equivalent to optogalvanic spectroscopy with several important advantages. (authors)
[en] Status Update of the Precision Attenuation Length Measurement Setup The planned JUNO detector is a 20 kt liquid scintillator neutrino detector. Its primary goal is the determination of the neutrino mass hierarchy. This will be done by precision measurements of the reactor antineutrino survival probability. Due to the spherical detector's diameter of approx. 35.5 m, the optical parameters, especially the attenuation length, of the scintillator have to be known precisely and have to be very good to achieve the required energy resolution of 3% rate at 1MeV. To determine one of the crucial optical parameters, the attenuation length, a new spectrometer experiment, called PALM, was built. Unless the commercially available spectrometers with light paths up to 10 cm, this spectrometer is able to measure light paths up to 2.8 m through the medium, making it possible to determine the attenuation length very precisely. This talk gives a status update on the commissioned PALM setup.
[en] A unit of automatic control of discrete recording of spectrum in the DFS-24 spectrometer device used in the flowsheet of photon counting during monochannel digital accumulation has been described. Discrete regime of spectrum scanning can be used alongside with continuous one which can be ensured by the DFS-24 device
[en] The refraction of rays in the Savart polariscope is different from the isotropic medium. We have analysed and discussed the refraction of rays in the Savart polariscope on the basis of the Snell law. The refraction formulae of the extraordinary rays and ordinary rays were derived. Results obtained may provide theoretical and practical guide lines for studying, developing and engineering of polarization interference imaging spectrometer. (classical areas of phenomenology)
[en] We review recent advances in optical and magnetooptical (MO) scatterometry applied to periodically ordered nano structures such as periodically patterned lines, wires, dots, or holes. The techniques are based on spectroscopic ellipsometry (SE), either in the basic or generalized modes, Mueller matrix polarimetry, and MO spectroscopy mainly based on MO Kerr effect measurements. We briefly present experimental setups, commonly used theoretical approaches, and experimental results obtained by SE and MO spectroscopic analyses of various samples. The reviewed analyses are mainly related to monitoring optical critical dimensions such as the widths, depths, and periods of the patterned elements, their real shapes, and their line edge or linewidth roughness. We also discuss the advantages and disadvantages of the optical spectroscopic techniques compared to direct monitoring techniques.
[en] Magnitudes of linear polarization in the UBVRI bands have been measured for about 30 background stars in the direction of the Chamaeleon I dark cloud. In addition, high-resolution spectroscopic observations in the wavelength ranges of the atomic species Ca II and Ca I and of the molecular species CH and CH+ have been performed towards the highly reddened and early-type stars selected from the polarimetry sample. The data have been used to study the magnetic-field structure, the relation between polarization and extinction, and the relation between molecular abundances and polarization properties in the cloud. In this contribution they present some of the results
[en] The present review reflects the importance of dielectric barrier discharges for optical spectrometric detection in analytical chemistry. In contrast to usual discharges with a direct current the electrodes are separated by at least one dielectric barrier. There are two main features of the dielectric barrier discharges: they can serve as dissociation and excitation devices as well as ionization sources, respectively. This article portrays various application fields of dielectric barrier discharges in analytical chemistry used for elemental and molecular detection with optical spectrometry. - Highlights: • Dielectric barrier discharges for optical spectrometric detection in analytical chemistry. • Electrodes are separated by at least one dielectric barrier. • A DBD can serve as dissociation and excitation device and as ionization source. • Various application fields of DBDs for elemental and molecular detection with optical spectrometry.
[en] Complete text of publication follows. Glow discharges have become a standard tool for both elemental analysis and depth profiling of solid conducting and non-conducting materials. They are used in continuous and pulsed mode. The application of pulsed GD (PGD) has made significant progress over the last years; however the peculiar behaviour of rf discharges on pulsed ignition has not yet been fully understood. The analytical performance of a GD spectrometer depends mainly on two physical processes: sputtering and excitation or ionisation of the respective atoms in the negative glow. Therefore, the effect of a pulsed rf-power supply on the latter effect will be studied, using a commercial rf-GD-OES instrument (RF 5000 JY) from Horiba Jobin Yvon, Longjumeau, France. Copper has been chosen to perform a more detailed study of the emission profiles for a wide range of transitions between different states, giving an interest insight into the excitation processes in the GD plasma. Different measurement conditions have been applied and the effect of frequency, duty cycle, pulse length, pressure, power and concentration upon the emission profile has been studied and compared to earlier obtained data; more precisely concerning the presence of the pre-peak, observed at the beginning of the rf PGD. It has been observed that the intensity of the pre-peak can be 10-30 times as large as the plateau value for resonant lines and 5-10 times in case of metastable transitions. Its presence could be due to the lack of self-absorption during the first 50ms, and not to the ignition of the plasma. Also, pressure and power changes have their respective influence on the pre-peak behaviour, so do the pulse frequency and the plasma-off time. These results could make it possible to use time-discrimination in the data acquisition with short pulsed discharges and the use of the pre-peak could increase the linearity of calibration curves when working at high concentrations, thus better precision should be obtained. The authors acknowledge the financial support from the EC through the Marie Curie Research Training Network (MRTN-CT-2006-035459).