Organic materials, lasers

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. 

Heat dissipation occurs primarily by conduction, therefore organic materials having low thermal conductivities typically need less laser power for recording than other materials. Indeed, it has been found that a writing energy of just 0.1 nanojoule per square micron can give rise to a temperature rise sufficient to melt many plastics and dyes.196... 

Besides the well-established chromatographic/mass spectrometric or spectroscopic methods there is always a need for complementary methods for the study of organic materials from art objects. The application of laser desorption/ionisation mass spectrometry (LDI-MS) methods to such materials has been reported only sporadically [12, 45 48] however, it is apparently increasing in importance. After GALDI-MS had been applied to triterpenoid resins, as described in Section 5.2, this relatively simple method was evaluated for a wider range of binders and other organic substances used for the production or conservation of artwork. Reference substances as well as original samples from works of art were analysed. 

Baudelet M., Boueri M., Yu J., Mao S., Piscitelli V., Mao X., Russo R. 2007. Time-resolved ultraviolet laser-induced breakdown spectroscopy for organic material analysis. Spectrochimica Acta Part B Atomic Spectroscopy, 20,1329-1334. 

In addition to display applications, researchers are also exploring the use of vapor-deposited organic materials in devices such as photovoltaics [11], organic lasers [12], and organic thin-film transistors (TFTs) [13]. 

CO2 is the gas generally used for mass-spectrometric analysis. More recently CO and O2 have also been used in high temperature conversion of organic material and in laser probe preparation techniques. A wide variety of methods have been described to liberate oxygen from the various oxygen-containing compounds. 

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