Polarization analyses of readout signals in phase change material incorporating a Solid Immersion Lens (SIL)

Comprehensive analyses based on rigorous vector diffraction theory have been presented to simulate the readout signal contrast using SIL in reading phase change recording disk. De-polarized reflected light (y-polarized from x-polarized incident beam) results in the reduction of total signal contrast, and becomes more obvious for high numerical aperture (NA) systems. Due to the signal degradation from de-polarized reflected light, filtering de-polarized light is applied to signal detection. The x-polarized contrast is a factor 1.0 to 1.35 higher than the conventional detection contrast (x+y polarized) at different gap widths, at a cost of 0 to 25 percent total intensity reduction.