254
T. Okura
When the wavelength interval λ =
ω
n
(Fig. 10.23a, c), the spectral components
will not be measured evenly (Fig. 10.24). However, a large n in Eq. 10.23 will result
in a smaller error.
(b-2) Linear Array Grating Spectrometer
The entrance slit wavelength width ω in is always larger than the pixel width ω pix−w .
The slit function of the signal from a pixel of the linear array in a spectrometer cannot
be triangular. This is shown in Fig. 10.25, which is the same as Fig. 10.23b, where
the exit slit wavelength width ω exit is replaced by the pixel width wavelength ω pix−w .
This slit function is lined-up with the interval of the pixel interval wavelength
width ω pix−i . When the entrance slit wavelength width ω in is n times the pixel
interval wavelength width ω pix−i (Eq. 10.24), all the spectral components are evaluated evenly. The relationship between the mechanical size of the entrance slit W in
and pixel interval W pix−i is also described in Eq. 10.24.
Fig. 10.24 Wavelength interval and wavelength resolution
Fig. 10.25 Slit function of a
pixel