Andor Technology Mechelle - Echelle Grating Efficiency

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Version 4.2 rev 06 Oct 2020
8.2 x 8.2 mm / 512 x 512 sensor
Lowest Noise Imaging EMCCD
Mechelle
4.8 ecHelle gRating eFFiciency
Echelle gratings produce a series of different orders over the entire spectral range of interest (e.g. the ME5000 model
produce around 80 orders). When the grating is used in the Littrow angle, the grating efciency at its maximum in the
middle of each order. However the efciency drops to about half of this value at the extremities of each order. An Echelle
grating is blazed for all wavelengths in a spectral range for a given diffraction order.
Figure 22: An Illustration of Echelle Grating Efciency
The effect of the grating efciency can be clearly observed when a Continuous Wave (CW) light source is used. Figure
23 below shows a typical spectrum of deuterium CW light source. Echelle grating efciency can be corrected with the
aid of Standard lamps (also known as “black body” lamps) and software logarithm.
Figure 23: Deuterium CW Light Source Spectrum