The present invention relates to an appliance for reading from and/or
writing to optical recording media 1 having a first laser diode LD1 for
producing a first scanning beam AS1 at a first wavelength .lamda..sub.1
and having a second laser diode LD2 for producing a second scanning beam
AS2 at a second wavelength .lamda..sub.2, with the scanning beams AS1,
AS2 running along a common optical axis 9, scanning an information layer
6 on the recording medium 1 and falling on a single photodetector 8 in
order to produce an information signal IS, with a beam combination
element being arranged at one point on the optical axis 9. According to
the invention, the beam combination element is a diffraction grating 12.