Application of superresolution technology in optical disks

Super resolution,which allows the readout of information beyond the optical cutoff frequency given by 2NA/λ,is an alternative way to increase the recording density without the need to reduce the spot size by increasing the numerical aperture of the objective lens and/or reducing the wavelength of the light source.Superresolution can be achieved either by modifying the optical system or by changing the disk structure,and is based on the nonlinear response of a recording media to readout laser light intensity.Since superresolution technology was first applied to magnetooptical disks.It has undergone rapid development,and is an effective way to increase the recording density of optical disks.