A method includes detecting noise in a laser output of a heat assisted magnetic recording device. The noise is converted into an electrical signal including a numerical value. A least significant digit of the numerical value is selected. The least significant digit is concatenated with another least significant digit from another detecting of another noise in another laser output to form a number.

Provided is a reproducing apparatus including: a reproduction signal generating circuit that calculates a first difference signal which is a difference between a first light receiving signal obtained by the first light receiving element and a second light receiving signal obtained by the second light receiving element, and a second difference signal which is a difference between a third light receiving signal obtained by the third light receiving element and a fourth light receiving signal obtained by the fourth light receiving element, and uses the first difference signal, the second difference signal, a phase difference between a crosstalk component and an average phase of the signal light beam, and an optical path length difference between the signal light beam and the reference light beam to obtain a reproduction signal; and a phase extraction circuit that obtains a successive change amount and updates with a successive variation.

A lens holder includes a holder body and a winding wire wound around the holder body. The holder body includes a winding body, a first projection and a second projection each projecting from a surface of the holder body, and a winding terminal positioned between the first projection and the second projection, and provided on the surface of the holder body. A part of the winding wire is wound around the winding body to form a coil. An end of the winding wire is wound around the second projection and connected to the winding terminal.

A lens holder includes a holder body and a winding wire wound around the holder body. The holder body includes a winding body, a first projection and a second projection each projecting from a surface of the holder body, and a winding terminal positioned between the first projection and the second projection, and provided on the surface of the holder body. A part of the winding wire is wound around the winding body to form a coil. An end of the winding wire is wound around the second projection and connected to the winding terminal.

A reproducing device (100) includes (i) an optical pickup (6) for irradiating, with reproduction light, an optical disk (1) which is a super-resolution medium, (ii) an RF signal processing circuit (9) for converting, into a reproduction signal, light which reflected off optical disk (1), (iii) an i-MLSE detecting section (141) for evaluating quality of the reproduction signal, and (iv) a spherical aberration correcting section (142) for correcting a spherical aberration by using a result of evaluation of the quality of the reproduction signal.

A reproducing device (100) includes (i) an optical pickup (6) for irradiating, with reproduction light, an optical disk (1) which is a super-resolution medium, (ii) an RF signal processing circuit (9) for converting, into a reproduction signal, light which reflected off optical disk (1), (iii) an i-MLSE detecting section (141) for evaluating quality of the reproduction signal, and (iv) a spherical aberration correcting section (142) for correcting a spherical aberration by using a result of evaluation of the quality of the reproduction signal.

Provided is a reproducing apparatus including: a reproduction signal generating circuit that calculates a first difference signal which is a difference between a first light receiving signal obtained by the first light receiving element and a second light receiving signal obtained by the second light receiving element, and a second difference signal which is a difference between a third light receiving signal obtained by the third light receiving element and a fourth light receiving signal obtained by the fourth light receiving element, and uses the first difference signal, the second difference signal, a phase difference between a crosstalk component and an average phase of the signal light beam, and an optical path length difference between the signal light beam and the reference light beam to obtain a reproduction signal; and a phase extraction circuit that obtains a successive change amount and updates with a successive variation.

A reproducing device (100) includes (i) an optical pickup (6) for irradiating, with reproduction light, an optical disk (1) which is a super-resolution medium, (ii) an RF signal processing circuit (9) for converting, into a reproduction signal, light which reflected off optical disk (1), (iii) an i-MLSE detecting section (141) for evaluating quality of the reproduction signal, and (iv) a spherical aberration correcting section (142) for correcting a spherical aberration by using a result of evaluation of the quality of the reproduction signal.

A reproducing device (100) includes (i) an optical pickup (6) for irradiating, with reproduction light, an optical disk (1) which is a super-resolution medium, (ii) an RF signal processing circuit (9) for converting, into a reproduction signal, light which reflected off optical disk (1), (iii) an i-MLSE detecting section (141) for evaluating quality of the reproduction signal, and (iv) a spherical aberration correcting section (142) for correcting a spherical aberration by using a result of evaluation of the quality of the reproduction signal.

Methods and apparatus for recording and retrieval of optically readable data employ a recording medium (100) which comprises an optically active material (108) able to induce a change in properties of the medium in the presence of optical radiation having a first characteristic, such as a first optical frequency, and wherein the change in properties can be inhibited by optical radiation having a second characteristic, such as a second optical frequency. During recording, a region of the recording medium (100) is irradiated with a first beam (506) of optical radiation having the first characteristic, the beam having a sufficient intensity within a central portion of the irradiated region and being of sufficient duration to cause an optically induced change in properties of the recording medium. Simultaneously, the region of the recording medium (100) is irradiated with a second beam (508) of optical radiation having the second characteristic, the second beam having a local intensity minimum within the central portion of the irradiated region, and a local intensity maximum in at least one portion of the irradiated region adjacent to the central portion which is sufficient to inhibit the optically induced change in properties of the recording medium. A similar method is employed for retrieval, however the intensity of the first beam (506) is reduced to prevent changes in material properties within the recording medium (100).