Model near field calculations for optical data storage readout

We investigate the near field distribution of light diffracted from deep grooves of sub-wavelength lateral dimensions, carved on a flat metallic surface. It is shown that, in spite of multiple interaction, the reflected field presents, for s polarization, peaks very localized on the groove positions, and whose amplitude increases with the groove depth. For p polarization, however, the near field does not follow the surface profile. This permits us to establish for s polarization a threshold in order to distinguish signals produced on reflection from grooves having different profiles. This is of guidance in diffractive modeling of readout systems of high density optical-disks. (C) 1996 American Institute of Physics.