A device for acquiring information contained in a phosphor layer comprises a light source (2) for irradiating the phosphor layer (1) with excitation light (3) that is suitable for exciting emission light (4) in the phosphor layer (1), a detector (6) for detecting the emission light (4) that has been excited in the phosphor layer (1), and a filter device (8), arranged between the phosphor layer (1) and the detector (6), that is substantially transparent in a first wavelength range (W1) of the emission light (4) and substantially non-transparent in a second wavelength range (W2) of the excitation light (3). To increase the reliability during the acquisition of the emission light, the filter device (8) is made substantially non-transparent in at least a third wavelength range (W3) having longer wavelengths than the second wavelength range (W2) of the excitation light (3).