Optical scattering cuvette

Figure 1. Schematic of optical scattering cuvette at distal end of shunt.

Optical Applications. Vitreous siUca is ideal for many optical appHcations because of its excellent ultraviolet transmission, resistance to radiation darkening, optical polishing properties, and physical and chemical stabiUty. It is used for prisms, lenses, cells, wiadows, and other optical components where ultraviolet transmission is critical. Cuvettes used ia scatter and spectrophotometer cells are manufactured from fused siUca and fused quart2 because of the transmissive properties and high purity (222). 

The experimental setup employed 785 nm excitation with a 90° collection geometry. Each spectrum was obtained with excitation power 300 mW and integration time equivalent to 2.5 min. Because filtered serum is nearly transparent at 785 nm, excitation of Raman scattering is effectively along the entire laser path, creating a line source in the cuvette. Thus, the authors surmise that better collection efficiency could be obtained with optics designed specifically for this type of source, as opposed to the standard spherical lens they employed. 

The molecular absorption phenomenon can only be accurately measured provided that the ratio of transmitted intensity, 7, of the UV radiation to that of the incident intensity, /q, is due to the presence of the dissolved solute and not to scattering of the incident beam. If the optical windows (see below) absorb UV radiation, then the absorbance which is related to the logarithm of the ratio ///q would cause an increase in sample absorbance hence, this would lead to an erroneous result. The student will encounter two types of optical window material. One consists of glass and is said to have a UV cutoff (UV wavelengths below this would absorb) of 300 nm (near UV) and the other consists of quartz with a UV cutoff of 190 nm. The rectangular cuvette is depicted as follows ... 

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