Laser energy

A small but artistically interesting use of fluorspar is ia the productioa of vases, cups, and other ornamental objects popularly known as Blue John, after the Blue John Mine, Derbyshire, U.K. Optical quaUty fluorite, sometimes from natural crystals, but more often artificially grown, is important ia use as iafrared transmission wiadows and leases (70) and optical components of high energy laser systems (see Infrared and RAMAN spectroscopy Lasers) (71). 

Fig. 16. Maximum achievable signal-to-noise ratio (SNR) on read-out of different writable optical data storage systems as a function of the writing energy (laser power) (121). SQS = Organic dye system (WORM) PC = phase change system (TeSeSb) MO = magnetooptical system (GbTbFe). See text.

Other. Alkali chiorochromate compounds, including cesium chiorochromate, CsCrCl, are ferromagnetic substances being studied for potential apphcation in optically-read computer memory devices. Cesium has also been used in vapor glow lamps (44), vapor rectifiers, and high energy lasers (qv)... 

Molybdenum is used for high energy laser mirrors which require water cooling. Corrosive action of the circulating cooling water can be prevented by coating the waterways with a thin film of tungsten by chemical vapour deposition. US Pat Application 308976 (1982). 

An important consideration when employing high-energy laser systems to do pulsed TR spectroscopy experiments is to make sure the molecule or state is not perturbed. For pulsed excitation, the fraction of molecules photolyzed is described by a photoaltemation parameter F that can be expressed as... 

A number of points are clear. First, in all cases the major expense of laser photons is the hardware, not the energy (even at Austin prices). Secondly, the intrinsically greater efficiency of the lower-energy lasers, especially the economic attractiveness of the CO2 laser, is evident. One can easily understand why laser chemistry schemes based upon multiphoton infrared absorption attract so much effort. Thirdly, on a per-unit-time basis the ion laser is more than twice as expensive to operate than even the rather exotic excimer laser. This is because of the inherent energetic inefficiency of the rare-gas plasma as a gain medium and because of the extrinsic, and hideous, expense of ion laser plasma tubes (and their poor reliability). 

Photo/Thermal Reactions. The fifth basic class of photopolymer chemistry that can be used in commercial applications is based more on physical changes in a polymer-based matrix than on chemical reactions. A recent application of this technology is the laser ablation (77) of an organic coating on a flat support to directly produce a printing plate. The availability of newer high energy lasers will allow more applications to be based on the photo/thermal mechanism. 

Attempts to Trigger Lightning Using High-Energy Lasers... 

Gonzalez et al. 2008). Laser ablation is a direct sampling technique by which a high energy laser is focused on the surface of a material and atoms, ions, and particles are ejected. The particles, which are chemically representative of the bulk sample, are then transported into an ICPMS for analysis. In LIBS, a luminous, short-lived plasma is created on the sample surface by the focused laser beam and its emission spectra are analyzed to provide both qualitative and quantitative chemical compositional analysis (Cremers... 

A serious problem in LA-ICP-MS described in the literature on many occasions is the time-dependent elemental fraction (so-called ablation fractionation ) occurring during laser ablation and the transport process of ablated material, or during atomization and ionization processes in the inductively coupled plasma.20-22 Numerous papers focus on the study of fraction effects in LA-ICP-MS as a function of experimental parameters applied during laser ablation (such as laser energy, laser power density, laser pulse duration, wave length of laser beam, ablation spot size,... 

Methods to form image detectors by ion-implanting Hg ions into a CdTe substrate and thereafter annealing the substrate with a high-energy laser are disclosed in US-A-4242149. 

When the sample is irradiated by two high-energy laser beams with frequencies vi and V2 (vi > v2) in a collinear direction (Fig. 3-42), these two beams interact coherently to produce the strong scattered light of frequency 2vi — v2. If V2 is tuned to a resonance condition such that v2 = vi — vm where vM is a frequency of a Raman-active mode of the sample, then a strong... 

Ablation is a powerful technique that uses high-energy lasers to vaporize or ablate materials from the surface. The wavelength of the laser is tuned for the specific material to achieve maximum absorption of the energy, most often ultraviolet. The target is vaporized, creating a plume of neutral metal atoms. The plume is then cooled with a carrier gas to form clusters. It is possible to couple laser evaporation with laser pyrolysis to form alloys. 

Recently, several small scale applications have been developed such as removal of lead in flotation waste [2], in phosphate glasses [3], to obtain clean steel without deoxidation with aluminum [4], preparation of lanthanum [5], high purity CaF2 (99.99%) is used in thermal plasma for purification of silicon [6], in the manufacturing of optical compounds for high energy lasers and infrared transmission systems [7]. 

Matrix-assisted laser desorption/ionization (MALDI) On applying a high-energy laser beam to a biomolecule (co-crystallized in a matrix), it rapidly turns into a gas and ionizes. 

In MALDI, the sample is embedded in a non-volatile matrix such as nicotinic acid or 2,5-dihydroxybenzoic acid. The sample matrix is introduced into the mass spectrometer, charged to high-voltage and exposed to a high-energy laser beam. The matrix material is chosen to absorb the laser radiation and the radiation causes the matrix and sample molecules to vaporise or sputter into the gas phase. 

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