Laser, tunable characteristics

Developing complex diagnostics including semiconductor surface sensors and optical sensors, based on tunable laser diodes for sensing both gaseous and liquid characteristics. 

This type of research uses pulsed and tunable lasers as an excitation source. The rare-earth ion is excited selectively, and its decay is analyzed. The shape of the decay curve is characteristic of the physical processes in the compound under study (9). For a detailed review the reader is referred to the literature (S). Here we give some results for... 

Table 2. Characteristic properties of tunable dye lasers with different pumping sources (cw = continuous wave)...

Since the invention of the tunable laser chemists have dreamed of using its characteristic high intensity and spectral purity to control the selectivity of chemical reactions. When such selectivity can be achieved via use of spectral resolution, for example, photodissociation of different isotopic variants of the same chemical species, the desired control of product formation has been demonstrated. On the other hand, when such selectivity is sought via concentration of energy in particular bonds, rapid intramolecular energy transfer has prevented, for the examples studied to date, the desired control of product formation. 

Resonant Scattering Processes. One of the problems which has attracted great interest this year is again due to the development of finely tunable dye lasers as light sources, and poses the question of what will be the temporal characteristics of excitation by a pulse as it is tuned through an atomic or molecular resonance,... 

ABSTRACT. Tunable coherent radiation in the ultraviolet and vacuum ultraviolet has been generated by stimulated Raman scattering, by anti-Stokes Raman lasers, and by frequency mixing processes in nonlinear media. The theory and experimental progress in the development of these laser-driven sources is reviewed, and examples of available systems and their characteristics are discussed. Various applications in spectroscopy of radiation tunable in the wavelength region 200-90 nm are presented. 

On the other hand, those characteristics of the laser that are important for its applications in spectroscopy are treated in more detail. Examples are the frequency spectmm of different types of lasers, their linewidths, amplitude and frequency stability, tunability, and tuning ranges. The optical components such as mirrors, prisms, and gratings, and the experimental equipment of spectroscopy, for example, monochromators, interferometers, photon detectors, etc., are discussed extensively because detailed knowledge of modem spectroscopic equipment may be cmcial for the successfiil performance of an experiment. 

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