Ruby, spectrum

In their early study of the ruby spectrum Sugano and Tanabe [44] attributed the zfs to the trigonal anisotropy of the spin-orbit coupling. In a simplified form the anisotropic s.o.c. hamiltonian may be written as ... 

Luminescence spectra of kyanite obtained at low spectral resolution often contain a narrow line peaking at 694.3 nm with a very long decay time (Fig. 5.29a). Such a line is typical for ruby luminescence, which was confirmed by the ruby spectrum obtained under the same experimental conditions as for kyanite (Fig. 5.29b). Spectra obtained at higher resolution reveal that there actually is a doublet at 694.3 and 692.8 nm, which corresponds to the ruby spectrum (Fig. 5.29c). Besides, the excitation spectrum of the line at 694.3 nm (Fig. 5.29d) reveals two maxima peaking at 410 and 550 nm which correspond well to the natural corundum excitation spectrum (Tarashchan 1978). Thus, we conclude that those lines do not belong to kyanite, but rather to ruby micro-inclusions inside the... 

Neodymium and YAG Lasers. The principle of neodymium and YAG lasers is very similar to that of the ruby laser. Neodymium ions (Nd +) are used in place of Cr + and are often distributed in glass rather than in alumina. The light from the neodymium laser has a wavelength of 1060 nm (1.06 xm) it emits in the infrared region of the electromagnetic spectrum. Yttrium (Y) ions in alumina (A) compose a form of the naturally occurring garnet (G), hence the name, YAG laser. Like the ruby laser, the Nd and YAG lasers operate from three- and four-level excited-state processes. 

The work of Horn and Gupta [76]-[77], as analyzed by Sharma and Gupta [78], on the optical spectrum of ruby under shock compression in both... 

P.D. Horn and Y.M. Gupta, Luminescence R-Line Spectrum of Ruby Crystals Shocked to 125 kbar along the Crystal c-Axis, Phys. Rev. B 39, 973-979 (1989). 

A surprising observation was made in the first experiments on the flash photolysis of CdS and CdS/ZnS co-colloids Immediately after the flash from, a frequency doubled ruby laser (X = 347.2 nm photon energy, = 3.57 eV) the absorption spectrum of the hydrated electron was recorded. This species disappeared within 5 to 10 microseconds. More recent studies showed that the quantum yield increased... 

Lasers produce spatially narrow and very intense beams of radiation, and lately have become very important sources for use in the UV/VIS and IR regions of the spectrum. Dye lasers (with a fluorescent organic dye as the active substance) can be tuned over a wavelength range of, for instance, 20-50 nm. Typical solid-state lasers are the ruby laser (0.05% Cr/Al203 694.3 nm) and the Nd YAG laser (Nd3+ in an yttrium aluminium garnet host 1.06 pm). 

A rather specialized emission source, which is applicable to the study of small samples or localized areas on a larger one, is the laser microprobe. A pulsed ruby laser beam is focused onto the surface of the sample to produce a signal from a localized area ca. 50 pm in diameter. The spectrum produced is similar to that produced by arc/spark sources and is processed by similar optical systems. 

Figure 1.8 Light absorption and emission in ruby (a) energy levels of Cr3+ ions and (b) absorption spectrum of ruby.

Figure 11.19. The absorption spectrum of ruby.(54) X = Incident light perpendicular to c-axis II = incident light parallel to c-axis.

Figure 14. (Upper panel) The ruby fluorescence spectrum measured in quasi-hydrostatic conditions at 7.7 GPa. (Lower panel) The empirical law describing ruby Ri line shift with pressure [96] is also reported.

Figure 11. Absorption spectrum of 3,5-dinitroanisole radical anion, produced from 3,5-dinitroanisole by. (a) irradiation in alkaline acetonitrile-water with a 20 ps discharge flash (b) irradiation in alkaline acetonitrile-water with a frequency doubled ruby laser pulse (347 nm, 6 ns) (c) electrolysis in acetonitrile in the presence of tetraethyl ammonium perchlorate.

Fig. 3 Ruby R-line spectrum at 21.9 GPa and 300 K, as measured from a pressure cell containing Pr metal [145]. The total wavelength shift at this pressure is some 8 nm...

Figure 6.93 Transmission spectrum for sapphire and ruby. From K. M. Ralls, T. H. Courtney, and J. Wulff, Introduction to Materials Science and Engineering. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission John Wiley Sons, Inc.

Very broadly speaking, two situations have to be considered in explaining devices such as those we have mentioned. In the first, which is relevant to the ruby laser and to phosphors for fluorescent lights, the light is emitted by an impurity ion in a host lattice. We are concerned here with what is essentially an atomic spectrum modified by the lattice. In the second case, which applies to LEDs and the gallium arsenide laser, the optical properties of the delocalised electrons in the bulk solid are important. 

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