Pupil replication with crossed gratings in an AR display is modelled and characterised. It is found that, compared to linear gratings, crossed gratings in a hexagonal lattice offer an additional degree of freedom to control the angular spread of pupils and can potentially improve the uniformity of the pupil map. In terms of characterisation, the model explains well the trend observed in experiments. Good quantitative agreement of the relative pupil intensity is obtained for a number of the measured waveguides.
Heat-assisted magnetic recording (HAMR) is a potential enabling technology for ultrahigh density data storage
systems. In HAMR, a near-field transducer (NFT) delivers a subdiffraction heat spot to record bits of data
on a high-anisotropy magnetic media. We developed an intuitive 1D Fourier model that expedites the analysis
and design of the NFT. Among other strengths, the simple model predicts rather surprisingly and in agreement
with 3D simulations, that for metallic nanoresonators the longitudinal component of the electric field dominates
the heat transfer to the media. The proposed Fourier model serves well as a platform to study electromagnetic
behavior such as field confinement and heat spot generation of 3D NFT designs.
A simplified analytic model is employed to demonstrate how surface plasmons propagating between the slits
in Young's interference experiment can modulate the spatial coherence of the light field radiated by the two
slits. The model is verified by comparison with results from rigorous numerical simulations. Our simulations
reveal that the coherence can indeed be enhanced or suppressed, depending on the distance between the slits.
Extending our analysis to a three-slit geometry, the effect on the degree of modulation when another slit is placed
between the two slits is investigated. It is found that, compared to the two-slit case, the center slit serves not
only as a barrier that can reduce the modulation, but can also act to enhance the amount of modulation. These
results are promising for the development of novel "coherence converting" devices with suitable metallic arrays
of subwavelength apertures.