The invention is directed to an arrangement for an optical system for polarization-dependent, time-resolved optical spectroscopy, in particular a spectrometer that includes a polarization device which has a crystal polarizer and includes a light entry area which is arranged upstream of the polarization device and which is formed in such a way as to enclose a spatial acceptance angle of the crystal polarizer, and also that includes a light exit area which is arranged downstream of the polarization device, wherein an intermediate area which connects the light entry area and the light exit area is formed in the polarization device with a path length of at most approximately 4 mm which is traversed in the crystal polarizer by light impinging within the spatial acceptance angle.