Simulations of heat generation and conduction on a land/groove disc
We applied the finite-difference time-domain (FDTD) method to an optical disc to estimate the energy absorption inside a multi-layered disc with land-and-groove structure. The FDTD method was developed to measure the electromagnetic fields generated by diffraction in a near-field. Afterwards we analyzed the heat conduction. We found that temperature transition depended not only on conductivity but on the initial distribution of the heat and on disc geometry.
Design of a Near-Field Probe for Optical Recording Using a 3-Dimensional Finite Difference Time Domain Method
Tapered dielectric near-field probes are designed for optical recording by means of a 3-Dimensional finite difference time domain (FDTD) method. Probe fabrication is attempted with a double-exposure holographic technique.
Feasibility Study of High Density Land/Groove Recording on Magnetooptical Disks
Land/groove recording on a magnetooptical disk with polyolefin and polycarbonate substrates was demonstrated. The laser wavelength, numerical aperture of the objective lens and focused beam spot size were 680 nm, 0.55 and 1.15 µm, respectively. With a groove pitch of 1.3 µm, a carrier-to-noise ratio (CNR) of more than 45 dB with 0.6 µm mark length and crosstalk of less than -30 dB with 2.4 µm mark length were obtained. The effect of crosstalk cancellation in the polymer substrates was confirmed. Decreasing the vertical birefringence of the substrate improved the jitter and the CNR. The crosserase margin was 0.8 mW. It was identified that the CNR declined with the CNR phase shift.