13
1
5
3
7
2
6
4
8
SPECTRAL BANDWIDTH CALCULATION
FORMULA & GRATINGS LIST
SPECTRAL BANDWIDTH CALCULATION FORMULA
Spectral bandwidth = slit width X Reciprocal Dispersion
NOTE1, This formula only for slit width
＞
100
µ
m.
NOTE2
, The real measurement bandwidth value slightly more calculation value.
NOTE3, The Reciprocal Dispersion of different spectrograph are shown in the
SPECIFICATION table,and the Reciprocal Dispersion value only for
1200g/mm gratings. So
you need the below formula to calculate other groove density gratings:
Real Reciprocal Dispersion = Reciprocal Dispersion value in the SPECIFICATION table X
1200/ real grating groove density
e.g.1
: For Omni-
λ
300 monochromator with 600g/mm gratings
Real Reciprocal Dispersion = 2.7
X
1200/600 = 5.4nm/mm
When the slitwidth is 2mm, the spectral width =5.4
X
2=10.8nm
Also, according to above formula to calculate the slit width of fixed spectral width
e.g.2
: For Omni-
λ
300 monochromator with 600g/mm gratings
Real Reciprocal Dispersion = 2.7
X
1200/600 = 5.4nm/mm
The slit width(@
5.4nm spectral width) = 5.4/5.4=1mm
