10 Hardware of Near-Infrared Spectroscopy
247
Fig. 10.17 Czerny-Turner
linear array spectrometer
λ max =
10
6
N
· (sin(θ − γ ) + sin β 2 )
(10.9)
All configurations of the spectrometer can be determined based on the above
calculations.
(b) Concave Grating with Constant Interval Grooves
When a concave grating with constant interval grooves is used, the incident light
through an entrance slit on the Rowland circle [6] is diffracted and focused back
onto the same Rowland circle (Fig. 10.18). The Rowland circle has a diameter R,
which is the radius of curvature of the concave grating and is in contact with its
surface.
Fig. 10.18 A concave
grating mount for a linear
array spectrometer