Monochromators with diffraction grating

Fluorescence Instrumentation and Measurements. Fluorescence spectra of the FS samples were obtained on a steady state spectrofluorometer of modular construction with a 1000 W xenon arc lamp and tandem quarter meter excitation monochromator and quarter meter analysis monochromator. The diffraction gratings In the excitation monochromators have blaze angles that allow maximum light transmission at a wavelength of 240 nm. Uncorrected spectra were taken under front-face Illumination with exciting light at 260 nm. Monomer fluorescence was measured at 280 nm and exclmer fluorescence was measured at 330 nm, where there Is no overlap of exclmer and monomer bands. 

All sources of error can be divided into systematic and casual. The instrumental polarization (IP) of a telesc ope-polarimeter system is of the first type. It is stipulated, mainly, by that fact that the polarization degree of the light (both reflected and transmitted) varies with incident angle on the optical elements. In astronomical observations such surfaces are the telescopic mirrors, monochromator mirror, diffraction grating, filters, polarizers, SPSP etc. Therefore, even unpolarized light that falls on the main telescope mirror becomes partially elliptically polarized. The contribution of the polarization attributable to the instrument (see [2], for example) is Pj, (pj Qj, Uj and Vj. 

The construction of a typical monochromator is shown in Figure 10.12. Radiation from the source enters the monochromator through an entrance slit. The radiation is collected by a collimating mirror, which reflects a parallel beam of radiation to a diffraction grating. The diffraction grating is an optically reflecting surface with... 

Typical grating monochromator with inset showing the dispersion of the radiation by the diffraction grating. 

Figure 10. Experimental set-up for Raman spectroscopy with the evanescent wave. For excitation, an argon ion laser was used ( 488 nm, output power 1.5 W cw). The material of the reflection plate is fused silica or super dense flint glass. Monochromator Ebert mount Jarrell-Ash 30 cm focal length diffraction gratings 150 or 600 g/mm.

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