Laser materials

Nd-doped YAl3(B03)4 is a self frequency doubling laser material that produces 0.53 jum laser output from 1.06 jum. (Lu et al, 1989). Accordingly, this material combines the functions of a conventional Nd-YAG laser and a SHG material like KTP. Another significant development in this field is the discovery of upconversion laser 

Abraham, F., Boivin, J. C., Mairesse, G. Nowogrocki, G. (1990) Solid State Ionics 40-41, 934. 

Chandra, S. (1981) Superionic Solids Principles and Applications, North-Holland, Amsterdam. 

Chemla, D. S. Zyss, J. (eds) (1987) Nonlinear Properties of Organic Molecules and Crystals, Academic Press, New York. 

Bouas-Laurent, H. (eds) (1990) Photochromism Molecules and Systems, Elsevier, Amsterdam. 

The core components of soUd-state lasers are laser materials that allow for the inversion of population and amplification of radiation through stimulated emission. The properties of the laser materials determine the ways to design pumping system and laser resonator of a soUd-state laser. Because the characteristics of laser active centers are determined by the physical processes related to the laser materials, while there are various possible interactions between the active centers and the electromagnetic radiations, the interrelationship among the composition, stmcture, properties, and functionality of laser materials is very complicated, leading the research in this field to be unlimited. 

Similar to most advanced engineering materials, transparent ceramic laser materials also have various requirements for practical appUcations. The fabrication and processing process should be reliable, consistent, feasible, reproducible, energy saving, cost-effective, and scalable. More importantly, the compositions, both the main components and the dopants, must be under good control. 

The materials should meet specific requirements in compositions at microscopic levels. The substitution sites of low symmetry should be specific and well-defined in monochromatic lasers, while inhomogeneous broadening of fines are preferred in 

Neodynium ultraphosphate, NdPjO (5.185), is an efficient and much-used laser material. The cyclic tetrametaphosphates MNdP40j2 (M = Li, Na, K), the ortho phosphates M3Nd(P04)2, M = Na, K, fluorapatite doped with Nd + or Ho + and Nd-doped metaphosphate glasses are also efficient laser materials. 

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Europium oxide is now widely used as a phospor activator and europium-activated yttrium vanadate is in commercial use as the red phosphor in color TV tubes. Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years. 

Organic Dye Lasers. Organic dye lasers represent the only weU-developed laser type in which the active medium is a Hquid (39,40). The laser materials are dyestuffs, of which a common example is rhodamine 6G [989-38-8]. The dye is dissolved in very low concentration in a solvent such as methyl alcohol [67-56-17, CH OH. Only small amounts of dye are needed to produce a considerable effect on the optical properties of the solution. 

S. S. Charschan, ed., UM Guide to Laser Materials Processing, Laser Institute of America, Orlando, Fla., 1993. 

F. Hide, M.A. Dtaz-Gatcia, B.J. Schwarts, M.R. Andersson, P Qibing, A.J. Hecger, Semiconducting polymers a new class of solid-state laser materials. Science 1996, 273, 1833. 

LED do not have sufficient power for single mode fiber applications which, because of the smaller cross-sections, require more powerful lasers. The CVD of LED and laser materials is described in Ch. 15. 

Reisfeld R, Jorgensen CK (1988) Excited States of Chromium(III) in Translucent Glass-Ceramics as Prospective Laser Materials. 69 63-96 Reisfeld R (1996) Laser Based on Sol-Gel Technology. 85 215-234... 

Among all semiconductor NPs, metal selenides have been the focus of great attention due to their importance in various applications such as thermoelectric cooling materials, optical filters and sensors, optical recording materials, solar cells, superionic materials, laser materials and biological labels. Many synthetic methods have been developed for the preparation of relatively monodispersed selenide nanopartides (Murray et al., 1993 Korgel... 

Neodymium-doped yttrium-aluminum garnet is among the most commonly applied laser material and has broad application (neodymium-YAG). 

Silver-colored, ductile metal that is attacked slowly by air and water. The element exhibits interesting magnetic properties. Found in television tubes. Laser material such as YAG (yttrium-aluminum garnet) doped with holmium (as well as chromium and thulium) can be applied in medicine, especially in sensitive eye operations. 

The fabrication of lasers based upon color centers adds a further dimension to the laser wavelengths available. Ordinary F centers do not exhibit laser action, but F centers that have a dopant cation next to the anion vacancy are satisfactory. These are typified by FLi centers, which consist of an F center with a lithium ion neighbor (Fig. 9.26a). Crystals of KC1 or RbCl doped with LiCl, containing FLi centers have been found to be good laser materials yielding emission lines with wavelengths between 2.45 and 3.45 p,m. A unique property of these crystals is that in the excited state an anion adjacent to the FLi center moves into an interstitial position... 

The latest advancement in femtosecond (fs)-based micromachining technology has opened a new window of opportunity for fabrication of microdevices. Direct exposure of most solid materials (including fused silica glass) to high power fs laser pulses may lead to the ablation of a thin layer of materials at the laser focal point13. Due to the multiphoton nature of the laser-material interaction, the ablation process can be conducted on the material surface as well as within its... 

The choice of sensor material determines range, sensitivity, and stability. By considering the latter factors, it is found that inorganic insulating compounds, such as most lamp phosphors and many solid state laser materials, are the most suitable materials for thermometric applications. Indeed, these materials are most commonly used in the existing commercial fluorescence thermometer schemes. 

The yttrium aluminum garnet crystal, Y3 AI5O12, doped withNd + ions, is a well-known solid state laser material (abbreviated to Nd YAG). If the fluorescence lifetime of the main laser emission is 230 /rs and the quantum efficiency of the corresponding emitting level is 0.9, determine (a) the radiative lifetime and... 

Due to the large variety of laser materials and pumping methods, it is almost impossible to catalog all the laser devices that have been demonstrated up to date. However, we can make a classification of the laser systems based on the different types of active media. We will briefly comment on the basis and properties of some specific types of laser systems, which are representative of different laser schemes. 

The experiments have demonstrated the importance of characterizing ESA in order to assess the ability of a system as a laser material. Eor example, if the ESA process takes place in the spectral region of the laser emission, the laser gain can be strongly affected, and laser action could even be prevented. On the other hand, if ESA occurs in the pumping region of the laser material, the pump efficiency could be reduced, and ESA could also be a source of thermal loading for the laser system. 

Cr + ions in aluminum oxide (the ruby laser) show a sharp emission (the so-called Ri emission line) at 694.3 nm. To a good approximation, the shape of this emission is Lorentzian, with Av = 330 GHz at room temperature, (a) Provided that the measured peak transition cross section is c = 2.5 x 10 ° cm and the refractive index is = 1.76, use the formula demonstrated in the previous exercise to estimate the radiative lifetime, (b) Since the measured room temperature fluorescence lifetime is 3 ms, determine the quantum efficiency for this laser material. 

EXAMPLE 6.4 Using the Sugano-Tanabe diagram of Figure 6.8, estimate the energy for the lowest energy transition in V MgF2 (AE —2500 cm ) and infer details about the emission of this laser material. The Racah parameters for the free ions are B = 755 cm and C = 3257 cm f... 

In the first topic, we will briefly describe a semi-empirical method that is commonly nsed to estimate the radiative transition probabilities from energy levels of (RE) + ions in crystals. This is certainly very nsefnl in order to determine the efficiency of a (RE) + based system as a luminescent or laser material. In the previous chapter (Section 5.7), we have described a method for determining the qnantnm efficiency of a Inminescent system. However, the application of that method is limited to certain... 

Powell, R. C., Physics of Solid-State Laser Materials, AIP Press/Springer, New York (1997). Riseberg, L. A., and Weber, M. J., in Progress in Optics 14, ed. E. Wolf, North-Holland, Amsterdam (1975). 

Polymer-salt complexes involving the tripositive lanthanides have been investigated from the standpoint of conductivity, which is observed to be very low. In addition, the neutral complex Nd(DMP)3 (DMP = 2,2,6,6-tetraethyl,-3,5-heptane dionate) will dissolve in PEO although not electrically conductive this polymer may have utility as a laser material. To... 

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