https://doi.org/10.1351/goldbook.D01842
Double (spectral) beam spectrometers are used where two samples are to be excited by two different wavelengths. A double- (
synchronous
) beam spectrometer
is a luminescence spectrometer
in which both the excitation and emission monochromators scan the excitation and emission spectra simultaneously, usually with a fixed wavelength
difference between excitation and emission.