Patent ID: 8238215

Claim:
A recording and reproducing apparatus for recording and reproducing information on and from a recording medium, the recording medium including at least one recording layer on which information is recorded by multi-photon absorption, and a servo layer disposed in a laminated direction with respect to the recording layer and having a track for guiding a beam spot of laser light having a first wavelength for reproducing and a beam spot of laser light having a second wavelength for recording along a scanning trajectory, the servo layer and the at least one recording layer constituting a set of layers, and a plurality of sets of layers being formed in the laminated direction, the recording and reproducing apparatus comprising: an optical pickup device; and a servo circuit for controlling the optical pickup device, wherein the optical pickup device includes: an optical system for irradiating the laser light having the first wavelength, the laser light having the second wavelength, and laser light having a third wavelength for scanning the servo layer on the recording medium and guiding reflection light of the laser light having the first wavelength reflected from the recording medium, and the reflection light of the laser light having the third wavelength reflected from the recording medium, to a corresponding photodetector; and an actuator for causing the laser light having the first wavelength and the laser light having the second wavelength to follow the recording layer, and causing the laser light having the third wavelength to follow the servo layer, wherein when recording information on the recording layer, the servo circuit is operable to position the laser light having the third wavelength on the track on the servo layer, based on a detection signal from the photodetector for receiving the laser light having the third wavelength, and to generate a servo signal for causing the laser light having the first wavelength and the laser light having the second wavelength to scan along the scanning trajectory on the recording layer to be recorded so as to supply the servo signal to the actuator, and the optical system includes; a integrating element for integrating only the laser light having the first wavelength and the laser light having the second wavelength to guide the laser light having the first wavelength and the laser light having the second wavelength to the same position of the recording medium, and a separating element for separating only the reflection light of the laser light having the first wavelength reflected from the recording medium, and the reflection light of the laser light having the second wavelength reflected from the recording medium, and guiding the separated light of the laser light having the first wavelength to the photodetector for reproducing.