Tuned laser

This reaction has been carried out with a carbon dioxide laser line tuned to the wavelength of 10.61 p.m, which corresponds to the spacing of the lowest few states of the SF ladder. The laser is a high power TEA laser with pulse duration around 100 ns, so that there is no time for energy transfer by coUisions. This example shows the potential for breakup of individual molecules by a tuned laser. As with other laser chemistry, there is interest in driving the dissociation reaction in selected directions, to produce breakup in specific controllable reaction channels. 

In AFS, the analyte is introduced into an atomiser (flame, plasma, glow discharge, furnace) and excited by monochromatic radiation emitted by a primary source. The latter can be a continuous source (xenon lamp) or a line source (HCL, EDL, or tuned laser). Subsequently, the fluorescence radiation is measured. In the past, AFS has been used for elemental analysis. It has better sensitivity than many atomic absorption techniques, and offers a substantially longer linear range. However, despite these advantages, it has not gained the widespread usage of atomic absorption or emission techniques. The problem in AFS has been to obtain a... 

A combination of both methods was realized by Uehara et al. 85,88) They investigated the Stark spectrum of polyatomic molecules in strong electric fields by probing the different Stark components with the Zeeman-tuned laser line. Since the molecular constants of the vibrational ground state are often known from microwave investiga-... 

The author also studied the possibility of enhancing the electron density and temperature of an alkali-seeded plasma by pumping the resonance lines of the alkali atoms with a suitably tuned laser 283)... 

Toschek and coworkers 345) used a technique called tuned laser differential spectrometry which is based on simultaneous interaction of gas atoms with two different laser beams, one of these being a weak probe beam the tuning of which scans the saturation on the common level of the two transitions induced by the other beam 346) The experiment employed the two He-Ne laser lines at X = 1.15 ju and X = 0.6328 which share the common lower level. 

Fourier-transform infrared (FTIR) spectrometers encode infrared wavenumbers by moving a mirror in a Michelson interferometer which results in a unique, path-dependent pattern of interference for each light wavelength in the IR beam. FTIRs have come to totally dominate the IR market and are the means by which most of the work described in this review was accomplished. Only for some special applications (modulation spectra and time-dependence studies) are dispersive-based (scanning monochromator or tuned laser) spectrometers still used. The advantages of the FTIR approach are that the entire spectral region of interest can... 

Resonance ionization mass spectrometry (RIMS) is much more efficient at getting ions into the detectors. First, atoms are removed from the sample surface with a pulsed laser, which can release the atoms thermally without ionizing them. Then, by using carefully tuned lasers, the element of interest in the resulting gas plume can be ionized at almost 100% efficiency, while other elements are not ionized at all. The ions are extracted into a time-of-flight... 

M. de Labachelerie, G. Passedat Mode-hop suppression of Littrow grating-tuned lasers. Appl. Opt. 32, 269 (1993)... 

The AVLIS process consists of a laser system and a separator system. The latter contains a vaporizer and a collector. The working medium is metallic uranium that is melted and vaporized to form an atomic vapor stream. The vapor stream flows through the collector where it is illuminated by precisely tuned laser light. The selected atoms become charged by photoionization and are removed from the vapor stream by an electronic field. 

Laser isotope separation techniques Laser-based isotope enrichment techniques deploy selective photo-excitation principles to excite a particular isotope as an atom or molecule (Rao 2003). Each device consists of three parts the laser system, the optical system, and the separation module. These methods include the atomic vapor laser isotope separation (AVLIS) that uses a fine-tuned laser beam to selectively ionize vapors of atomic the molecular laser isotope separation (MLIS), and separation of isotopes by laser excitation (SD EX) that use a laser to selectively dissociate or excite molecules. 

Graham-Rowe D (2009) A new twist to tuning lasers. Nat Photonics 3 182-183... 

Principles and Characteristics The analytical capabilities of the conventional fluorescence (CF) technique (c/r. Chp. 1.4.2) are enhanced by the use of lasers as excitation sources. These allow precise activation of fluorophores with finely tuned laser-induced emission. The laser provides a very selective means of populating excited states and the study of the spectra of radiation emitted as these states decay is generally known as laser-induced fluorescence (LIF, either atomic or molecular fluorescence) [105] or laser-excited atomic fluorescence spectrometry (LEAFS). In LIF an absorption spectrum is obtained by measuring the excitation spectrum for creating fluorescing excited state... 

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