Lasers crystals

Loncar, M. Scherer, A. Qiu, Y., Photonic crystal laser sources for chemical detection, Appl. Phys. Lett. 2003, 82, 4648... 

Compact and stable devices are available that take advantage of the improved quality of the crystal lasers, as well as increased pump efficiencies. Hundreds of different models of Nd + based lasers have demonstrated laser action (Kaminskii, 1981). It is possible to operate these Nd + solid state lasers in the continuous regime, with output powers ranging from 1 W to 1000 W. Pulsed operation is also possible, with a pulse length from the picosecond range, via mode-locking, to tens of nanoseconds by Q-switch operation. 

Cao, J.R., Kuang, W., Choi, S.-J., Lee, P.-T., O Brien, J.D., Dapkus, P.D., 2003, Threshold dependence on the spectral alignment between the quantum-well gain peak and the cavity resonance in InGaAsP photonic crystal lasers, Appl. Phys. Lett. 83(20) 4107-4109. 

In order to overcome these problems, interest was focussed on that portion of the organic matter trapped in mineral precipitates which formed synchronously with sedimentation. In these cases, the material is hermetically sealed in the crystalline matter and may survive with relatively little subsequent alteration. Such preservation is common in cherts which are chemical precipitates of silica and now comist of fine grained quartz. These rocks offer the best chance for successful preservation of truely Precambrian molecular fossils. Modem microprobes and spectrophotometer microscopes allow the non-destructive analysis of organic matter enclosed in mineral crystals. Laser bombardment of microscopic... 

The literature on mineral luminescence is somewhat bimodal in character. On one hand those mineral structures that have proved useful as phosphors or as crystal lasers have been studied in great detail and the physics of the energy transfer processes are often well known. The luminescence characteristics of many other minerals... 

Energy transfer in crystal lasers allows lasing at room temperature. 

The development of up-conversion fiber lasers, especially in the visible, is assisted by the availability of intense semiconductor lasers and mini-crystal lasers for pump sources. The various energy levels involved in pumping and lasing transitions are detailed in Sec. 8.4 and in related energy level diagrams. 

Figure 3. Number of different ion-crystal laser combinations grouped by lasing...

Possible sensitizers for lanthanide and actinide ions include other lanthanide and actinide ions, other transition group ions, and molecular complexes. These may be present either as added impurities or as a component of the host. Of the many sensitization schemes reported, some offer only marginal improvement. The most efficient crystal laser is "alphabet" holmium Ho3+ sensitized by Er +, Tm3+, and Yb +... 

Kaminskii,A. A. "Crystal Lasers" Springer-Verlag Berlin, Heidelberg, New York, 1979. 

Figure 13. Raman spectrum of anatase natural crystal. Laser power was A50 mW at A880 A. Spectral slit width was 4 cm l. Reproduced with permission from Ref. 153. Copyright 1972 Appl. Spectrosc.

However, a major part of this power improvement was also due to massive gains in diode laser efficiency. Diverse commercial lasers, based upon single crystals, are typically no more than 10% to 20% in efiiciency, but usualty much less. It is typical for a crystal laser to have a "slope" efficiency of 2-5% with outputs less than 10 milliwatts. InGaAsP diode lasers are efficient by these standards with efficiencies greater than 20%. Strained layer quantum-weU structures have been measured with efficiencies in excess of 85% at 1500 nm. wavelength. Typical threshold currents for... 

Dong J, Ueda K, Yagl H, Kaminskii AA, Cai Z (2009) Comparative study the effect of Yb concentrations on laser characteristics of Yb YAG ceramics and crystals. Laser Phys Lett 6 282-289... 

Meng JY, Wang HX (2011) Single diode-pumped, 1.7 ns microchip laser by Nd YAG/Cr YAG composite crystal. Laser Phys 21 79-81... 

Yin L, Li GQ, Zhao SZ, Li X, Cheng K, Zhang G (2011) Continuous wave and passively Q-switched laser performanee of a composite crystal bonded with three Nd YV04 single crystals. Laser Phys 21 1151-1154... 

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