| 摘要 |
PROBLEM TO BE SOLVED: To improve recording density by irradiating a substrate changed from an opaque state to a transparent state with temperature by the light beam wherein light from a light source is focused with a focusing lens. SOLUTION: When a near-field light generating part 13 is irradiated with a laser beam, the distribution of temperature according to the distribution of beam intensity is produced on the surface. At this time, the light beam is transmitted only by the periphery around the center of the optical axis becoming transparent and becoming a critical temperature using the thin film of the near-field light generating part 13 as a substance whose transmitivity is changed by the beam temperature. That is, the light beam transmits a thermal aperture part 17 becoming the critical temperature or more and becoming transparent, and a small spot for the near-field light 18 is obtained as the gap (g) wherein the interval between the near-field light generating part 13 and a disk 2 is smaller than an incident light beam wavelength. And since a phase transition thin film 22 for recording formed on the surface of a disk substrate 21 is irradiated with the near-field light 18 of the small spot, high density recording for one bit information 23 is allowed. |
