An optical scanning device for scanning a recordable optical disk (
) with a laser beam having a linear polarisation. A quarter wave plate (
) is used to alter the polarisation of the beam on reflection from the disk. A partially polarising beam splitter (
) is used and arranged such that a proportion of intensity of the incident beam passed is greater than a proportion of intensity of the reflected beam. A relatively high optical signal power at the disk (
) can be achieved for recording purposes whilst allowing the beam splitter (
) to be manufactured in a relatively efficient manner.