Laser operation condition

Shown in Figure 7.9 [8] is the influence variations in gas temperature and electron density have on small-signal gain, a0. This calculation was carried out for a 1-1-8, C02-N2-He mixture for a fixed-discharge EjN typical of laser operating conditions. The conditions depicted in Figure 7.9 correspond to a... 

Thus, the hydrogenation process is shown to produce a good current confinement and high quantum efficiency. The stability of these lasers is also a question of importance. If good thermal stability of hydrogen-acceptor complexes has been already observed in InP Zn for example (Chevallier et al., 1989), more studies are needed to evaluate the laser stability under operating conditions. 

At higher Nd3+ concentrations the lifetime of the 4F upper state drops from about 200 ps in a typically 1 % doped material to about 5 ps at higher dopant concentrations. This is due to Nd-Nd defect interactions and associated changes in lattice vibration characteristics. Under these conditions, laser operation is no longer possible. 

This paper explores the trade-offs of gem damage during LIBS analysis and data quality under a variety of analytical conditions. Two lasers, a Big Sky Laser Technology (now Quantel USA) Nd-YAG nano-second laser operated at its fundamental wavelength of 1064 nm, and a Raydiance, Inc., pico-second laser operated at its fundamental wavelength of 1552 nm as well as harmonics at 776, 517.2, and 388 nm, are used in separate LIBS systems. Furthermore, the use of inert gas environment (He or Ar) is explored to increase peak intensities at lower laser power and sample damage. 

Norman, M. D., Pearson, N. J., Sharma, A., and Griffin, W. L. (1996). Quantitative analysis of trace elements in geological materials by laser ablation ICPMS instrumental operating conditions and calibration values of NIST glasses. Geostandards Newsletter 20 247-261. 

The components of an LED are similar to that of the laser diode, the differences between the two devices being largely dependent on the operating conditions and of course the nature of the output. 

Details of the laser system and the operating conditions employed to control the lasers have been described previously [6]. The system includes two independently operated distributed feedback (DFB) InGaAsP diode lasers tuned over the desired transitions near 1.34 p,m and 1.39 p,m i/ + I s bands)... 

These results are consistent with previous measurements which showed that CO concentration was lowest at the combustor operating conditions that most efficiently reduced the overall emission of toxic gases. Thus a measurement of CO concentration can serve as an effective indicator of combustor performance. The results demonstrate the applicability of multiplexed diode laser sensors for rapid, continuous measurements and control of multiple flowfield parameters, including trace species concentrations, in high-temperature combustion environments. 

The dimensions of the stainless-steel micro structured reformer are 75 mm x 45 mm x 110 mm. It consists of a stack of micro structured steel foils coated with catalyst and tempered by heating cartridges in the reactor housing. Laser-cut graphite foils were used to seal the reformer under operating conditions up to 200 °C at a flow rate up to 900 ml min-1 and a residence time of 0.07 s. 

Figure 6.10 Laser-induced fluorescence detection of a hemolysate of human erythrocytes. Conditions capillary, 110 cm X 20 jum I.D. fused silica capillary voltage, -29 kV detection, laser-induced fluorescence (LIF), argon ion laser operating at 275.4 nm. Peaks A, carbonic anhydrase B, methemoglobin C, hemoglobin A 1, 2, and 3, unknown. (Reprinted from Ref. 49 with permission.)...

Since it is estimated that the vibrational temperatures Tn and T2 can reach several thousand degrees, the population of vibrationally excited molecules becomes significant in typical laser discharges. Furthermore, the vibrational populations are strongly influenced by the extraction of laser optical power from the discharge. Therefore, it is expected that the electron kinetics will be influenced not only by the presence of vibrationally excited molecules in the discharge, but that these kinetics will also be a function of the operating conditions of the laser. 

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