Applications of Laser-Induced Time-Resolved Spectroscopic Techniques

Applications of Laser-Induced Time-Resolved Spectroscopic Techniques... 

The Applications of Laser-induced Time-resolved Spectroscopic Techniques chapter starts with a short description of laser-induced spectroscopies, which may be used in combination with laser-induced luminescence, namely Breakdown, Raman and Second Harmonic Generation. The chapter contains several examples of the application of laser-based spectroscopies in remote sensing and radiometric sorting of minerals. The proljlem of minerals as geomaterials for radioactive waste storage is also considered. 

The current detailed understanding of photo-induced electron transfer processes has been advanced dramatically by the development of modern spectroscopic methods. For example, the application of time-resolved optical spectroscopy has developed from modest beginnings (flash-phyotolysis with millisecond resolution) [108,109] to the current state of the art, where laser spectroscopy with nanosecond resolution [110-113] must be considered routine, and where picosecond [114-116] or even femtosecond resolution [117] is no longer uncommon. Other spectroscopic techniques that have been applied to the study of electron transfer processes include time-resolved Raman spectroscopy [118], (time resolved) electron spin... 

The spectroscopic methods are based on time-resolved pump-probe schemes where the collision-free regime is usually attained by using low pressure conditions. Application of various linear and non-linear laser techniques, such as LIF (laser-induced fluorescence), REMPI (resonant-enhanced multiphoton ionization) and CARS (coherent antistokes Raman spectroscopy) have provided detailed information on the internal states of nascent reaction products [58]. Obviously, an essential prerequisite for the application of these techniques is the knowledge of the spectroscopic properties of the products. 

The same equipment, which is used for time-resolved luminescence application is suitable for other laser-based spectroscopies. Thus several spectroscopic methods may be applied simultaneously. The mostly important technique, which may be used together with time-resolved luminescence, is laser-induced breakdown spectroscopy. Several books have been recently published devoted to Laser Induced Breakdown Spectroscopy (LIBS) (Cremers and Radziemski 2013 Miziolek et al. 2006 Singh and Thakur 2007 Noll 2012 Hahn and Omenetto 2010 Hahn and Omenetto 2012). LIBS aspects were considered applied to the analysis of minerals, rocks and related materials (Senesi 2014). Thus only the theoretical aspects which are the mostly relevant to our research devoted to the real time online quality control of minerals will be considered. 

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