Read-out enhancement of super-resolution near-field structures using the pit shape

The effect of the pit shape on the read-out signal of a super-resolution near-field structure optical memory was investigated with a view to improving the read-out characteristics. Finite difference time domain calculations were carried out in an effort to understand the effect of the pit shape on the optical near-field induced local heating and resulting signal enhancement. Calculations showed an increase in read-out signal intensity with increasing aspect ratio significantly larger than that which can be explained by area increase alone, in excellent agreement with experimental results.