Transmission range, of optical materials

Transmission Range of Optical Materials Transparency of Polymers Refractive Index of Polymers Dispersion of Optical Materials... 

Selecting Transmission Range of Optical Materials Selecting Transparency of Polymers Selecting Refractive Indices of Glasses Selecting Refractive Indices of Polymers... 

The term solid-state laser refers to lasers that use solids as their active medium. However, two kinds of materials are required a host crystal and an impurity dopant. The dopant is selected for its ability to form a population inversion. The Nd YAG laser, for example, uses a small number of neodymium ions as a dopant in the solid YAG (yttrium-aluminum-gar-net) crystal. Solid-state lasers are pumped with an outside source such as a flash lamp, arc lamp, or another laser. This energy is then absorbed by the dopant, raising the atoms to an excited state. Solid-state lasers are sought after because the active medium is relatively easy to handle and store. Also, because the wavelength they produce is within the transmission range of glass, they can be used with fiber optics. 

A thicker cell is possible if reticulated vitreous carbon (RVC) is used. For example, transmission of 13—45% for 100 p.p.i. (pores per inch) is possible for a 1.2-0.5 mm thick RVC plate. LIGAs are Llthogra-phic-GAlvanic structures that present some advantages over indium tin oxide (ITO) and metal meshes, namely improved stability, faster response times, and a greater range of electrode materials that can be used in the same cell. The electrodes are sandwiched between quartz rods coupled to the spectrometer using fiber optics. 

Transmission, or the conduction of radiant energy through a medium, is characterized by transmittance, which is the ratio of radiant power transmitted by a material to the incident radiant power. Transmittance over a wide range of optical wavelengths is one of the optical characteristics of diamond. 

There is a large range of optical cells available for spectroscopy measurements and they vary in materials, size, shape, and spectral transmission characteristics. The most commonly used sample holder in fluorescence spectroscopy is a 10 mm x 10 mm x 45 mm volume cuvette made from fused silica (for UV to near-lR operation), glass (visible), or a plastic that is often polycarbonate and disposable. Of course, it is essential that the cuvette chosen is suitable for the application and experiment and that it is clean, and handled with maximum care. 

For the purpose of a detailed materials characterization, the optical microscope has been supplanted by two more potent instruments the Transmission Electron Microscope (TEM) and the Scanning Electron Microscope (SEM). Because of its reasonable cost and the wide range of information that it provides in a timely manner, the SEM often replaces the optical microscope as the preferred starting tool for materials studies. 

The deposition in Ref 11, from an alkaline thiosulphate bath, was reported in the context of a general description of deposition of various materials by CD, and only a little characterization was reported. X-ray diffraction showed some Ag2S peaks. Optical spectroscopy showed a gradual decrease in transmission over a wide spectral range, and it would be difficult to extract a reliable value for the bandgap from the spectrum. 

KBr) substrate which has a natural transmission cut-off just below 400 cm-1. An understanding of this spectral range is important because it dictates the type of optics, optical materials and optical functional components, such as sources and detectors, that have to be used. 

In practice, a convenient range of solid crystalline materials, which can be polished to optical flatness over manageable areas, exists and includes silicon, quartz, and sapphire. The equivalent transmission through a block of amorphous quartz or silicon is 10—15%. This has so far precluded them from use, and limited the application to crystalline substrates. In aqueous solution, the most commonly use contrasts are D20, H20, and water (H20/D20 mixture) index matched to the solid phase. In D20, the refractive index (or scattering length density) difference between that and the solid phase is significantly different for silicon, quartz, and sapphire (see Table 1). 

Because of the optical quality and chemical stability of crystals, the low probability of non radiative processes and the wide transmission range, fluorides are the most appropriate materials for solid state lasers with specific wavelengths. Thus the 4f - 4f line emissions of lanthanide ions have been used in order to obtain infrared laser radiation up to 4.34 fxm and blue or green radiation by up-conversion pumping. Tunable laser operation in the ultraviolet has been demonstrated using the broad 5d 4f emission of Ce3+. Tunable lasers in the UV or IR ranges have also been experimented using Ag+, Pb+, 3d ions. 

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