Abstract: An installation and method for etching at least one wafer coated with an etch-ready, blank photosensitive layer is disclosed. In accordance with an embodiment, the wafer has thickness irregularities, wherein the wafer is arranged to be able to be submitted to irradiation-beam scanning, a sheet transparent to the radiation to which the photosensitive layer is sensitive covers the wafer, and a probe beam intended to reflect on the upper portion of the sheet perpendicularly to the irradiation beam spot on the photosensitive layer is provided.

Abstract: The invention relates to the field of the optical recording of information on a medium, such as an optical disc. To read an optical disc in super-resolution mode, a procedure for optimizing the power of the read laser beam is implemented. This optimization is based on the observation that a correlation exists between the power allowing the disc to be read without risk in super-resolution mode and the reflectivity of the sensitive layer containing the information. The reflectivity of the optical disc is measured for several power levels of the read laser, a critical power is determined on the basis of the reflectivity measurements made, and a read power sufficiently above the critical power, so as to be well outside a range of power levels entailing risks, is selected according to the critical power.

Abstract: The invention relates to the writing and optical reading of high-density information. The higher energy density at the center of the reading laser beam is used for modifying the energy structure of an active layer in such a way as to make it capable of bearing surface plasmons. The coupling of the laser beam and the active layer thus modified can then excite surface plasmons in an interface between a dielectric layer and the active layer. These surface plasmons are disturbed by physical marks having very small dimensions and written in the optical storage medium; these disturbances generate a remote-field optical response which can be detected by a detector. The operation is carried out in super-resolution, the surface plasmons being generated only at the center of the laser beam and not at the periphery. It is therefore possible to write and to read again marks having dimensions of size smaller than the theoretical resolution of the optical reading system.

Abstract: The invention relates to the field of the optical recording of information on a medium, such as an optical disc. To read an optical disc in super-resolution mode, a procedure for optimizing the power of the read laser beam is implemented. This optimization is based on the observation that a correlation exists between the power allowing the disc to be read without risk in super-resolution mode and the amplitude of the read signal which results from the reading of marks having the smallest possible dimension (marks 2 T). The amplitude of the optical disc is measured for several powers of decreasing values of the read laser, the reduction in amplitude is observed. A read power is selected as a function of the power for which a decrease (for example 5%) is noted in the amplitude measured at the start.

Abstract: The invention relates to the field of the optical recording of information on a medium, such as an optical disc. To read an optical disc in super-resolution mode, a procedure for optimizing the power of the read laser beam is implemented. This optimization is based on the observation that a correlation exists between the power allowing the disc to be read without risk in super-resolution mode and the reflectivity of the sensitive layer containing the information. The reflectivity of the optical disc is measured for several power levels of the read laser, a critical power is determined on the basis of the reflectivity measurements made, and a read power sufficiently above the critical power, so as to be well outside a range of power levels entailing risks, is selected according to the critical power.

Abstract: The invention relates to the writing and optical reading of high-density information. The higher energy density at the center of the reading laser beam is used for modifying the energy structure of an active layer in such a way as to make it capable of bearing surface plasmons. The coupling of the laser beam and the active layer thus modified can then excite surface plasmons in an interface between a dielectric layer and the active layer. These surface plasmons are disturbed by physical marks having very small dimensions and written in the optical storage medium; these disturbances generate a remote-field optical response which can be detected by a detector. The operation is carried out in super-resolution, the surface plasmons being generated only at the center of the laser beam and not at the periphery. It is therefore possible to write and to read again marks having dimensions of size smaller than the theoretical resolution of the optical reading system.

Abstract: The subject matter is a test device for characterizing a material used in an optical storage medium (10). It comprises a laser source (20) intended to direct an incident laser beam (21) towards the optical storage medium (10), the incident laser beam (21) passing through a focusing objective (22) before reaching the optical storage medium (10) and before being reflected thereat as a reflected laser beam (25). It furthermore comprises a diaphragm (23) for reducing the numerical aperture of the incident laser beam (21) below that of the focusing objective (22), this diaphragm (23) being situated between the laser source (20) and the focusing objective (22) and an interception device (26) for intercepting a cross section of the reflected laser beam (25) after it traverses the focusing objective (22) but before it reaches the diaphragm (23).

Abstract: An irreversible optical recording medium comprises at least a substrate whereon is arranged at least a photosensitive layer comprising a structured front face destined to receive an optical radiation during data recording and/or reading operations. The medium also comprises a track comprising raised zones, having: a height comprised between about 25 nm and about 35 nm for widths of raised zones comprised between 250 nm and 370 nm, and a height comprised between a minimum value varying substantially linearly, in decreasing manner, from 25 nm to 32 nm, and a maximum value substantially of 35 nm, for widths of raised zones comprised between 200 nm and 250 nm.