Silica optical

C. E. Arthur and J. Pawliszyn, Solid phase mia oextr action with thermal desorption using fused silica optical fibers . Awn/. Chem. 62 2145 - 2148 (1990). 

In Raman measurements [57], the 514-nm line of an Ar+ laser, the 325-nm line of a He-Cd laser, and the 244-nm line of an intracavity frequency-doubled Ar+ laser were employed. The incident laser beam was directed onto the sample surface under the back-scattering geometry, and the samples were kept at room temperature. In the 514-nm excitation, the scattered light was collected and dispersed in a SPEX 1403 double monochromator and detected with a photomultiplier. The laser output power was 300 mW. In the 325- and 244-nm excitations, the scattered light was collected with fused silica optics and was analyzed with a UV-enhanced CCD camera, using a Renishaw micro-Raman system 1000 spectrometer modified for use at 325 and 244 nm, respectively. A laser output of 10 mW was used, which resulted in an incident power at the sample of approximately 1.5 mW. The spectral resolution was approximately 2 cm k That no photoalteration of the samples occurred during the UV laser irradiation was ensured by confirming that the visible Raman spectra were unaltered after the UV Raman measurements. 

The construction of the optoelectronic interface can be based on a silicon photodiode since analytical and reference wavelengths are from the visible and the IR regions, respectively. The signals can be filtered out by optical filters (then two photodiodes are required) or one photodiode can be synchronised with modulation waves of the LEDs used. Finally, silica optical fibres can be used as light waveguides. The choice between single fibre or bundle is determined by the application of the sensor. 

To monitor the brain tissue, the fiber optic sensor based on the immobilization of a pH-sensitive dye, seminaphthorhodamine-1 carboxylate (SNARF-1C), was designed66. The dye-doped sol-gel was deposited onto the end of a 12 pm-diameter silica optical fiber and in vivo studies were performed. 

Carbon dioxide gas (CO2) exhibits a set of relatively strong absorption bands at approximately 2 pm, which coincides with the infra-red edge of the transmission band of silica optical fibres (see Figure 6). These absorption... 

Gel-derived glasses, 23 73-74 Gel-derived silica optical components, physical properties of, 23 75-76 Gel dyeing, 9 194 Gel effect, 16 281-282... 

The core of silica optical fibres contains some B2O3, Ge02, and P2O5. How do these impurities increase the refractive index ... 

Fig. 4. Arrangement for calibrating fluorescence spectrometer.17 L, xenon arc lamp Mi, excitation monochromator B, silica plate beam splitter. F, 0.5 mm. silica optical cell containing fluorescent screen solution Pi, monitoring multiplier phototube S, screen coated with MgO Mj, fluorescence monochromator Pa, fluorescence multiplier phototube.

The solution was contained in a cylindrical Pyrex or silica optical cell, 2.5 cm. in diameter and 2 cm. optical depth, fitted with a side arm of diameter about 1 cm. for connection to the vacuum line (see Fig. 10). Both phosphorescence and delayed fluorescence in fluid solution at room temperature are quenched by exceedingly low concentrations of molecular oxygen, and efficient deaeration is of the utmost importance. The following procedure was found to be satisfactory. The cell was first cooled in an acetone/C02 bath and pumped out. It was then isolated from the pump, refluxed to remove dissolved gas, cooled again in the... 

NOVA laser -vitreous silica optics for [SILICA - VITREOUS SILICA] (Vol 21)... 

In our earlier study, a pure fused silica optical fiber, SF-112UV (Sumitomo Co. Ltd., Japan), was chosen to serve as both delivery and collection fibers. The fiber has a core diameter of 114 pm, a total diameter of 125 pm, and an NA value of 0.20 [28]. Table 2.1 shows fibers with smaller i b values, and they would have been satisfactory, but we were also concerned about cost and continuing availability. There was no problem with using this fiber for both 720 and 785 nm excitation wavelengths. 

Author, C.L. and J. Pawliszyn (1990). Solid phase microextraction with thermal desorption fused silica optical fibers. Anal. Chem., 62(19) 2145-2148. 

Raman probes constructed from fused silica optical fibers have gained much attention recently. Typically, low-OH content fibers are utilized to reduce the fiber fluorescence. The probe design also includes filters at the distal end to suppress the fused silica Raman signal from the excitation fiber and suppress the elastically scattered fight entering the collection fibers.25 Commercial probes are now available and they offer ruggedness and easy access to samples with various special or geometrical constraints. 

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