Spectrometer echelle grating

Figure I. Schematic layout of an echelle grating waveguide spectrometer.

Felkel, H. L., Jr., "Evaluation of imaging detector coupled to an echelle grating spectrometer for atomic spectroscopy", Ph.D. Thesis, Purdue University, 1978. 

However, any spectrometer that uses CS and a double monochromator with an echelle grating makes it possible to reach any line within an extremely short period of time of much less than 1 s, as both the grating and the prism are stepper-motor controlled. This feature allows a fast sequential multi-element determination to be performed with the great advantage that flame conditions and burner... 

In addition, Echelle spectrometers are often used [50], By combination of an order-sorter and an Echelle grating either in parallel or in crossed-dispersion mode, high practical resolution (up to 300 000) can be realized with an instrument of fairly low focal length (down to 0.5 m) (Fig. 94). Therefore, the stability as well as the luminosity are high. By using an exit slit mask with a high number of preadjusted slits, highly flexible and rapid multielement determinations are possible. 

Keliher P. N. and Wohlers C. C. (1976) Echelle grating spectrometers in analytical spectrometry, Anal Chem 48 333A-340A. 

The spectrometer used is a modified Spectrametrics Spectraspan III echelle grating spectrometer with a quartz prism cross disperser. An echelle spectrometer was chosen because of its two dimensional format display. This format allows efficient simultaneous examination of a much wider spectral range than with a linear dispersion spectrometer when a two dimensional television camera type detector is used. 

The linear dispersion of an echelle grating dl/dX) is the focal length of the spectrometer (/) multiplied by the angular dispersion ... 

Figure 121 illustrates a sequential echelle spectrometer. Light from the entrance slit is directed by the collimating mirror to the echelle grating, and the diffracted beam is then reflected to the prism lense (order-sorter) and focusing lense. A two-dimensional spectrum is formed in the focal plane of the system. An aperture plate, which contains preset apertures, is mounted at the focal plane. Slits and mirrors are placed at appropriate positions on a... 

Table 31 Dispersion and bandpass values of a commercial instrument using an echelle grating with 79 groovesmm, with a blaze angle of 6T 26, and having the parent line at the 42nd order. Effective aperture of the spectrometer is f/8. The width of the entrance slit is 80 ptm, and the width of the exit slit is 40 fJm. (Unicam Analytical Systems Ltd.)...

FIGURE 3-17. Reflection echelle grating. [From G. J. Matz, Recent Advances in Echelle Spectrometer Analysis, American Laboratory, 4 (3), 75, (1973). Used by permission of International Scientific Communications, Inc.]... 

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