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Laser Ionization Techniques
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
In general, laser ionization spectroscopy is divided into two modalities, depending on whether the ions or the electrons are used for detection. The first of these is commonly known as resonance ionization spectroscopy or resonance-enhanced multiphoton ionization (REMPI). When electrons rather than ions are measured and analyzed, this is normally done in the form of zero electron kinetic energy (ZEKE); i.e., the ionizing photon step is to energy levels (or the continuum) very close to the threshold, so that the photoelectrons have extremely low kinetic energy. It should be noted that besides these main modalities, a number of experimental derivative techniques have been developed, such as, e.g., mass-analyzed threshold ionization (MATI).
Resonance Photoionization Spectroscopy
Published in Leon J. Radziemski, Richard W. Solarz, Jeffrey A. Paisner, Laser Spectroscopy and Its Applications, 2017
Jeffrey A. Paisner, Richard W. Solarz
The clear advantage of highly selective photoionization of atoms leads naturally to the concept of the selective detection of trace elements and even single atoms [Hurst, 1977, 1979; Bekov, 1978a]. The ability to detect ultralow fractions of long-lived radioisotopes, such as 10Be, 26Al, and 36Cl, with natural abundances of 1 part in 1010, 1014, and 1017, respectively, may have applications in nuclear physics and geophysics [Kudriavtsev, 1982]. The long lifetimes of these isotopes, of order 106 years, makes them difficult to detect by usual nuclear radiation counting methods. Resonance ionization spectroscopy could greatly aid in their detection.
Surface Phenomena
Published in Pramod K. Naik, Vacuum, 2018
Secondary electrons are generated by neutrals, ions, electrons, or photons with sufficiently high energy. Photoelectrons also can be considered as secondary electrons. When an ion or an excited atom approaches a metal surface, neutralization of the ion may occur and de-excitation or resonance ionization of the excited atom may take place. It is evident from the experimental data that electronic transitions involved in these processes are almost independent of the kinetic energy of the incident particle and are governed by its potential energy of excitation. The electronic transitions 52,53 include: Resonance neutralization Resonance ionization Auger de-excitation Auger neutralization
Investigation of a polarization-based Cr:forsterite laser resonator cavity
Published in Journal of Modern Optics, 2021
Siba Prasad Sahoo, V. S. Rawat, Jaya Mukherjee, Swarupananda Pradhan
In a laser resonator cavity, multiple round trips are required to build up the laser oscillation. Hence, the laser pulse is delayed with respect to the pump pulse which is known as the cavity buildup time. The cavity buildup time plays an important role in the temporal delay synchronization of multiple laser beams. For several laser spectroscopic experiments like resonance ionization spectroscopy, multiphoton absorption spectroscopy, coherent ant-stoke Raman spectroscopy (CARS), the delay of multiple laser beams needs to be synchronized. This is normally achieved either by electronic delay or by external optical delay. For this purpose, the polarization-based resonator cavity can be a good choice where the cavity buildup time, and hence the delay of the laser beam can be optically varied continuously. The cavity buildup time also plays an important role during the amplification process of a laser pulse. The signal pulse in the amplifier gain needs to be synchronized with the pump pulse for optimum extraction efficiency.