Relative laser intensity

The ratio Rqq, depends on a number of laboratory control parameters including f he relative laser intensities x, relative laser phase, and the ratio of e+1 and e via t. ... 

The fluorescence of the IF product molecules originating from the 6 11(0)+ -> band system was observed in the wavelength range 470-675 nm. The relative product vibrational population densities were determined from the measured fluorescence intensities of the individual bands, the relative laser intensities and the transition probabilities, as described in Ref. 12. At slow scanning speed the resolved rotational structure in the IF excitation spectrum was obtained, except in the vicinity of the band heads. It was analysed according to the procedure described below. 

Raman spectroscopy of matrix-isolated molecules carries some difficulties conneeted with the possibility of local heating of the matrix under laser irradiation. Besides, because of the relatively low intensity of Raman bands, higher concentrations of the species to be studied are needed in the matrix (the ratio of matrix gas to reagent = 100-500). As a result, the effective isolation of reactive intermediates is prevented. 

Note that parameters ft and 5 depend on signal amplifications in the utilized detectors and on the elements in the optical path (optical filter, spectral detection bands) only, while a and y are additionally influenced by relative excitation intensity. This is usually a fixed constant in wide-field microscopy but in confocal imaging laser line intensities are adjusted independently. Furthermore, note that the a factor equals 5 multiplied by y (see Appendix for further detail). 

Note that when S and D are collected simultaneously (typically for confocal imaging) 0 and S are independent of relative laser line intensities. 

Figure 32 Temporal profile of relative SHL intensity from alternate LB films of RuC18B and 2C18NB with subpicosecond laser pulses at 378 nm bold curve (A) experimental data, fine curve (B) calculated SHL intensity based on the excited-state lifetime of RuC18B in LB films.

Fluorescence intensity increases with the laser fluence, while its change was quite smooth even around the threshold. If a new process leading to ablation was involved in addition to the Si - Si annihilation, the relative fluorescence intensity of two excimers would not change furthermore above the threshold. Although the details are beyond our current knowledge, we conclude that the Si -Si annihilation is the origin of laser ablation in thiB fluence range. 

Figure 5. V4 Raman peaks for a stationary sample of NiTPP (0.2n ) in pyridine, with 406.7nm excitation. Arrows indicate the decreasing (1346cm ) and increasing (1369cm"l) relative band intensities at increasing laser power levels (1.5, 5, 10,...

Analysis of binding experiments required a careful comparison of (i) the MYKO 63 bands, either in the presence or absence of DNA bands and (ii) the DNA Raman bands, either in the presence or absence of MYKO 63 bands. This comparison was achieved by computer-subtracting variable amounts of one spectrum from another. Previously, the various spectra were normalized to the same relative Raman intensity, with the 934 cm band (CIO symmetric stretch) as an internal standard. The intensity of the CIO. scattering measures the combined effect of such experimental factors as counting time, optical alignment and laser power. 

If there is no fluctuation of laser intensity, we have to measure /q only once. Actually, the envelope of laser pulses changes in a relatively long time range (typically from several minutes to a few tens of minutes) because of the change of environmental factors such as room temperature and coolant temperature. There is also an intensity jitter caused by factors such as the mechanical vibration of mirrors and the timing jitter of electronics. Furthermore, in our system, the laser system is located about 15 m from the beam port to prevent radiation damage to the laser system. (Later, it was moved into a clean room, which was installed in the control room to keep the room temperature constant and to keep the laser system clean. The distance is about 10 m.) Therefore it is predicted that a slight tilt of a mirror placed upstream will cause a displacement of the laser pulse at the downstream position where the photodetector is placed. 

A plot of the relative transmission Tn of the dye sample versus the normalized laser intensity nc)(nc)s, according to (6), is shown in Fig. 2. It is seen that the absorption is completely bleached at very high light levels. 

Fig. 6. Relative laser pulse intensity versus time of a ruby giant pulse laser that was used to bleach a solution of metal-free phthalocyanine and transmission of the dye solution at the wavelength of the He—Ne—laser. (From Ref. 14>)...

While the amplitudes are hard to compare at different wavelengths (and the amplitudes in Fig. 3a are therefore only rough), these quantities are better defined at a given wavelength. We found that for long Apt their relative values (amplitude/average signal) did not depend on the probe laser intensity, which was varied over a factor of 3. 

In particular, note that many of our proposed control scenarios provide the experimentalist with a clear-cut statement of which parameters need to be varied to achieve control. Further, they tend to utilize relatively simple laser pulse (or CW) characteristics. Thus, our approach would apply to larger molecules in the same way as to smaller molecules that is, the experimentalist needs only to vary the indicated parameters (e.g., laser intensities, phases, etc.) and search for control in this parameter space. 

Figure 7.20 Selection of emission spectra of laser dyes. Horizontal axis, wavelength in nm vertical axis, relative emission intensity on a logarithmic scale...

The power dependence of the laser output was determined by plotting the relative output intensity vs. the relative pump intensity. In Figure 6 this function is clearly non-linear. Separate measurements show that the absolute threshold is 1 mJ, and the absolute output energy is 0.5 jiJ/pulse when the input energy is 2mJ/pulse. 

Relativity affects also significantly the scattering cross section of fast electrons in the Coulomb field of a nucleus, in the presence of an ultrastrong infrared laser. When the laser intensity becomes comparable or larger... 

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