There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

An optical pickup device includes a semiconductor laser that emits a laser beam, and an object lens that concentrates the laser beam emitted from the semiconductor laser on an optical disc. In this optical pickup device, an optical axis of the object lens is inclined with respect to an optical axis of the laser beam that is incident on the object lens so as to generate flares caused by coma aberration on an entrance side in a forward direction of pits of the optical disc.

An optical disk drive with multiple optical pick-up heads is provided. The optical disk drive includes an upper cover, a base, a first carrier member, a second carrier member, a first limiting member, and a second limiting member. The base is disposed under the upper cover. The first carrier member disposed on the base and has a first optical pick-up head. The second carrier member is disposed on the upper cover and has a second optical pick-up head. The first limiting member is used for disposing the first end of the second carrier member on the upper cover. The second limiting member is used for disposing the second end of the second carrier member on the upper cover. The length of the first limiting member is larger than that of the second limiting member.

Devices having at least one nanostructured layer derived from a binary sequence written onto an optical medium and methods of preparing the nanostructured layers.

Devices having at least one nanostructured layer derived from a binary sequence written onto an optical medium and methods of preparing the nanostructured layers.