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13.
Dispersing Elements and Systems
In first order,
Xj^
—
2>l^ and l_ =
2>l^/3.
The asymmetry in these wavelengths
about the peak is expected because the blaze fiinction is broader for the longer
wavelength.
The overall blaze fiinction ft)r wavelengths fi-om k_ to k^^ in first order is
shown in Fig. 13.10. The values of
v
used to calculate BF at other wavelengths are
given by
V
= w7r(A^ -
X)/)L
At the wavelengths
XJ^
given by Eq. (13.4.8), the
reader can verify that v = ±7r/2, as expected. Published efficiency curves of first-
order gratings with a greater than a few wavelengths are similar to the curve in
Fig. 13.10, though there is a differenc ...