Laser capability

There has been phenomenal expansion in the range of experiments coimected with light-molecule interactions. If one thinks of light as an electromagnetic (EM) wave, like any wave it has an amplittide, a frequency and a phase. The advent of the laser in 1960 completely revolutionized the control over all tluee of hese factors. The amplittide of the EM wave is related to its intensity current laser capabilities allow... 

The CO2 laser is a near-infrared gas laser capable of very high power and with an efficiency of about 20 per cent. CO2 has three normal modes of vibration Vj, the symmetric stretch, V2, the bending vibration, and V3, the antisymmetric stretch, with symmetry species (t+, ti , and (7+, and fundamental vibration wavenumbers of 1354, 673, and 2396 cm, respectively. Figure 9.16 shows some of the vibrational levels, the numbering of which is explained in footnote 4 of Chapter 4 (page 93), which are involved in the laser action. This occurs principally in the 3q22 transition, at about 10.6 pm, but may also be induced in the 3oli transition, at about 9.6 pm. 

An important development in the 1980s was the multiple stripe laser, capable of emission of high output powers. A number of stripes are placed on a bar perhaps 1 cm wide the output of the different stripes is coupled so that the device may be regarded as a single laser. Bars having continuous output up to 20 W are available in the aluminum gallium arsenide system. A number of bars may then be stacked to form two-dimensional arrays with high values of output power. 

Commercial frequency doublers have rehed on inorganic materials. The commercial future of doublers depends on not only the improvement in second-order materials but also the development of diode lasers capable of operating in the visible frequency domain. 

The resolution of the problems outlined above will obviously require much more theoretical and experimental work before the Raman technique will become universally applicable to the study of adsorption at metal surfaces. It will be interesting to see if tuneable lasers capable of operating in the near infrared will be... 

Ray and Coombe achieved lasing of the NCI (a)/I system by scaling-up their quenching experiment. The apparatus used for this demonstration is shown in Fig. 10. An excimer laser capable of providing 700 mJ pulses at 193 nm was used to generate high densities of NCI (a) metastables. The I laser cavity consisted of mirrors coated for > 99.5% reflectivity at 1.315 m. Representative I emission signals from this device are shown in Fig. 11. 

Neodymium yttrium-aluminum-gamet (Nd YAG) laser. Capable of penetrating tissue more deeply than other lasers, the Nd YAG makes blood clot quickly and can enable surgeons to see and work on parts of the body that could otherwise be reached only through open (invasive) surgery. 

A potentially more efficient method of enrichment would involve the use of sophisticated tunable lasers to ionize selectively and not fU. The ionized could then be made to react with negative ions to form another compound, easily separated from the mixture. For this method to work, we must construct lasers capable of producing radiation monochromatic enough to excite one isotope and not the other—a difficult challenge. 

With the advent of powerful lasers capable of generating short light pulses, a new era of research commenced [62-64]. Notably, the new light sources permit the measurement of lifetimes of excited states and the detection of short-lived intermediates such as free radicals and ions. The concomitant development of sophisticated detection methods has also brought about continuous progress during the... 

The use of low reaction chamber pressures (<1 bar) in the generic LCVD process yields large (>200 pm) diameter carbon fibers [8j with low growth rates (<10 pm/s) when a CO laser is used. Small (<20 pm) diameter carbon, boron and silicon fibers [1-2j [4j [7] are produced with equally low growth rates at <400 mbar when an efficient Ar laser is used. In summary, the low growth rates are due to the low pressure regime, and the fiber diameters are a function of the individual laser capability. 

Ihnable laser A laser, such as a dye laser, capable of continuously tuning the wavelength (or frequency) of its output radiation Continuous tuning means the smooth change of wavelength across the spectrum according to the controlled physical tuning of the oscillator. 

A new era of research in fluorescence spectroscopy has emerged with the advent of powerful lasers capable of generating short-lived pulses and with the simultaneous development of sophisticated detection methods. While research groups were previously limited to the study of processes on the microsecond and nanosecond time scale, these developments have expanded the accessible time scale to the pico- and femtosecond. Time-resolved fluorescent measurements are being used, for example, to unravel the dynamics of excited states (excitons) generated in conjugated polymer films (such as stimulated emission) and the processes that... 

Saturation spectroscopy makes it possible to attain very high spectral resolution by means of ultranarrow spectral saturation resonances whose width is five to six orders of magnitude smaller than the Doppler width. Tunable lasers capable of an emission... 

The LSRB provides a systems safety review of all Department of the Navy (DON) lasers used in combat, combat training, or classified in the interest of national security, and all lasers capable of exceeding Class 3a levels, including those used in optical fiber communication systems. If a system utilizes a laser, the system design must be reviewed and approved by the LSRB. It is the responsibility of the SSP to initiate contact with the LSRB and ensure all applicable requirements are satisfied. 

The analysis of fluid inclusions in minerals has also benefited from LA-ICP-MS, where the combination of a UV laser capable of ablating transparent minerals such as quartz with the elemental sensitivity of ICP-MS has enabled significant advances in several areas of research. Early work rapidly validated the approach and the technique is now gaining widespread acceptance across many facets of the geosciences. " Examples of applications include the analysis of inclusions in halite, evaluation of the emplacement history of mineral deposits, " and the evaluation of hydrothermal history of granitic bodies. ... 

This review is organized as follows Section 3.2 presents a brief discussion of the HF(DF) and CO chemical lasers which are at present the most highly developed systems for practical applications Section 3.3 outlines recent uses of small chemical lasers in laboratory research and Section 3.4 is devoted to a general discussion of problems in the search for new chemical lasers, with particular emphasis on electronic transition lasers capable of operation at visible wavelengths. 

Pulsed lasers capable of operation at repetition rates of 1 kHz and beyond have been constructed which make use of large transverse flows of reagents " see Figure 3.10. Design details of this type of laser have been given in refs. 123 and 125. These lasers have energies per pulse that are similar to those for the small flow-rate devices. The substantial improvement in... 

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