When chiral compounds are excited with unpolarized light, the difference in emission intensities of left- and right-handed circularly polarized light can be measured. This phenomenon is called circularly polarized luminescence (CPL). While circular dichroism provides information about the ground state of chiral molecules, CPL spectroscopy probes the excited states of chiral molecules.
By combining CPL with ECD, more structural information regarding chiral molecules can be obtained. To measure sharp CPL peaks at a high resolution, the CPL spectrometer uses two prism monochromators. Both the emission and excitation monochromators are equipped with continuously variable slit drives, which allow for an appropriate wavelength and band width selection.