摘要:
A variable refractive index unit (140) includes an optical axis and a first layer (144a, 146a, 146a′ of controllably variable refractive index extending in a first predetermined configuration in a first plane transverse the optical axis. A second, different layer (144b, 146b, 146b′ of controllably variable refractive index extends in a second predetermined configuration in a second, different plane transverse the optical axis. The second layer (144b, 146b, 146b′) overlaps the first layer (144a, 146a, 146a′).
摘要:
The invention relates to an optical recording and reproducing device. This device comprises means for receiving a recording medium (204), a radiation source (200) for producing a radiation beam, means (206) for detecting light corresponding to a holographic signal recorded in the recording medium, means (202) for directing the radiation beam towards the receiving means, and a reflective spatial light modulator (205) placed on the other side of the receiving means with respect to the detecting means.
摘要:
An optical device comprises a light source (301) for generating a radiation beam, a reflective diffractive structure (304) for reflecting and diffracting said radiation beam along an optical path (PP), imaging means (305) for imaging the radiation beam after it has been reflected and diffracted by said reflective diffractive structure, and a holographic beam splitter (303) between said reflective diffractive structure and said imaging means along said optical path. Such an optical device can be used for recording data into a holographic medium.
摘要:
An apparatus for enhanced transmission of radiation, comprising at least one radiation source (12), a metal plate (18) with a first (20) and a second (22) surface and at least one aperture (24) provided in the metal plate (18) and extending from the first (20) to the second (22) surface, the metal plate (18) having a periodic surface topography (26) provided on at least one of the first (20) and the second (22) surfaces, and radiation (13) coming from the radiation source (12) and being incident on one of the surfaces (20,22) of the metal plate (18) interacts with a surface plasmon mode on at least one of the surfaces of the metal plate (18), thereby enhancing transmission of radiation through the at least one aperture (24) of the metal plate (18). The apparatus for enhanced optical transmission comprises means (15) for generating radially polarized radiation (16), which is incident on one of the surfaces (20,22) of the metal plate (18) with a surface topography (26), resulting in a more efficient coupling of the radiation to the plasmons and thereby in a further enhancement of the optical transmission.
摘要:
An optical data storage system for recording and/or reading, using a radiation beam, having a wavelength λ, focused onto a data storage layer of an optical data storage medium is described. The system comprises the medium having a cover layer that is transparent to the focused radiation beam, an optical head, including an objective having a numerical aperture NA, said objective including a solid immersion lens that is adapted for being present at a free working distance of smaller than λ/10 from an outermost surface of said medium. The optical head comprises a first adjustable optical element corresponding to the solid immersion lens, means for axially moving the first optical element and dynamically keeping constant the distance between cover layer and solid immersion tens, a second adjustable optical element, means for dynamically adjusting the second optical element for changing the focal position of the focal point of the focused radiation beam relative to an exit surface of the solid immersion lens. This achieves reliable read-out and writing during cover layer thickness variations. Further a method is described for controlling such a system.