Optical Disk System Using a High-Numerical Aperture Single Objective Lens and a Blue LD

Abstract

An optical disk system using a blue laser diode and a single objective lens that has a numerical aperture of 0.7, is proposed. A sufficiently low jitter value was obtained with a read-only disk having 17-Gbyte capacity. The paper also includes discussion on the influence of the laser noise and RF modulation method on the playback signal.

Experimental Verification of Autoalignment for Focusing Unit of Near Field Recording System: Neural Network Approach

“…To increase the recording density, the use of shortwavelength light such as a blue laser has been proposed as a solution to recording density problems. 1,2) At the same time, current near-field recording (NFR) technology has been considered as a potential candidate for surpassing the farfield diffraction limit. [3][4][5] NFR requires the use of a solid immersion lens (SIL) 6) and there are serious issues that must be resolved, such as alignment or assembly problems between the objective lens and the SIL.…”

Evaluation and autoalignment method of the focusing unit for a near-field optical recording system

“…Thus, to increase the recording density, the use of short-wavelength light such as a blue laser has been proposed as a solution to solve the recording density issues. 1,2 At the same time, current near-field recording ͑NFR͒ technology has been considered as a strong candidate to surpass the far-field diffraction limit imposed by the nature of light in present optical data storage systems. [3][4][5][6] NFR uses a solid immersion lens 7 ͑SIL͒, which has a high refractive index ͑Ͼ1.0͒ to make the numerical aperture ͑NA͒ larger than 1.…”