Near-Field Optical Flying Head with A Triangular Aperture

Heat assisted magnetic recording head needs near-field element as a micro heat generator and light guide structure. We have proposed a triangular aperture as a near-filed element. Computer simulation using finite difference time domain (FDTD) method shows that the triangular aperture has a near-field peak on the edge perpendicular to the polarization of the incident light. Therefore it achieves a near-field spot less than 20 nm (FWHM) in the direction of the polarization, which is not limited by the aperture size. SNOM and contact slider experiments in the previous study also show that the triangular aperture is effective. We have also proposed a compact light guide structure with an optical fiber. Using light guide structure with a polarization maintaining fiber and micro optics can achieve a thin and small (1.6x1.6x0.7 mm) near-field flying head. The head was fabricated. Signal readout was demonstrated in flying operation. It could read 300 nm L&S patterns.