Is the CLARIOstar a monochromator or filter based microplate reader?
The CLARIOstar has the ability to measure fluorescence intensity and luminescence assays using optical filters, Advanced Monochromators or both in combination and an inline optical system automatically switches between monochromator and filters in both excitation and emission. The Linear Variable Filter Monochromators provide flexibility in wavelength and bandwidth selection while the filters are more sensitive since they have a higher percentage of light transmission than the monochromator.
Using a combination of filters for excitation and the monochromator for emission provides you with greater light transmission for excitation and with flexibility in emission wavelength and bandpass selection. Take the example of Alexa Fluor 350. For this you could select your 340 nm filter for excitation and then adjust the monochromator to the peak in emission (443 nm) and use a broad bandwidth of your choosing. In this way you would have intense excitation light AND collect data throughout the emission peak.
Get more information about LVF monochromators here.