Agilent Technologies 1100 Series Reference Manual page 245

The geometry of the grooves is optimized to reflect almost all of the incident
light, in the 1
ultra-violet range. Most of the remaining 30% of the light is reflected at zero
order, with no dispersion.
the grating.
Figure 80
The grating is turned using a 3-phase brushless DC motor, the position of the
grating determining the wavelength or wavelength range of the light falling
onto the flow cell. The grating can be programmed to change its position and
therefore the wavelength during a run.
For spectra acquisition and multi-wavelength detection, the grating rotates at
4000 rpm.
The excitation and emission gratings are similar in design, but have different
blaze wavelengths. The excitation grating reflects most 1
ultra-violet range around 250 nm, whereas the emission grating reflects better
in the visible range around 400 nm.
1100 Series FD Reference Manual
st
order and disperse it with about 70% efficiency in the
Figure 80
Dispersion of Light by a Grating
Introduction to the Fluorescence Detector
illustrates the light path at the surface of
st
order light in the
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