This page explains how to simulate localization of light at nanoscale ridge aperture as a near field transducer for HAMR.
In this page, we consider a layered structure shown below where a ridge aperture is formed in a silver layer. A focused beam (Scalar Gaussian beam is used here) with 800nm wavelength is illuminated onto the silver layer and strongly localized nanoscale light spot is formed around the aperture. The localized light spot heats a nanoscale region on the recording media, FePt, and this can be used as a heat source for HAMR.
The figures below show the optical absorption on the surface of the recording media, FePt and the transmission through aperture as a function of Ag thickness. The optical absorption data is recorded in a analysis group named "pabs_adv" and the transmission data is obtained from a parameter sweep named "thickness_sweep" set in the Optimization and Sweeps tab. Results are shown for two different sets of mesh sizes. Clearly the smaller mesh gives a more resolved answer, but the simulation time is substantially longer (minutes vs hours). Additional convergence testing will be required.
Absorption data in XY plane, roughly half way through FePt layer in vertical direction.
Power transmission as a function of transducer thickness
Script code used to adjust mesh override settings to reproduce these results:
# lower accuracy setnamed("data_layers_z","dz",3e-9); setnamed("all_layers_z","dz",10e-9); setnamed("aperture_xy","dx",20e-9); setnamed("aperture_xy","dy",20e-9); # higher accuracy setnamed("data_layers_z","dz",0.5e-9); setnamed("all_layers_z","dz",5e-9); setnamed("aperture_xy","dx",5e-9); setnamed("aperture_xy","dy",5e-9);
- N. Zhou, E. C. Kinzel, and X. Xu, "Nanoscale ridge aperture as near-field transducer for heat-assisted magnetic recording," APPLIED OPTICS Vol. 50, G42-46 (2011).