Bell Telephone Laboratories

Harold G Craighead

Richard E Howard

Donald M Tennant

Gerardo Beni

Susan Hackwood

A process employing bodies that are fabricated to have a specific configuration are useful for the storage of information such as digital data. In one embodiment a material, such as germanium, is etched to produce a structure having a multiplicity of columnar or conical features. By providing a sufficient number of these features per unit area, it is possible to store at a relatively high density a variety of information. This information storage is accomplished by melting the columns or cones in a localized area. If these structures are of the appropriate size and spacing, they appear optically absorbing before melting and a reflective region appears in the treated area. In this manner archival storage of densely packed information is possible.

Optical information storage and retrieval

A display cell having at least two states of different opacity, comprises a first material having a first index of refraction, a second material dispersed within the first material and having a second index of refraction, the difference between the first and the second indices of refraction being variable over a range of values, and means for varying the difference in index of refraction over a portion of the range. When the indices of refraction of the first and second material are substantially the same, the display is substantially transparent. Otherwise it is opaque or substantially less transparent.

Refractive index switchable display cell

Bodies having conical structures with dimensions on the order of the wavelength of visible light are prepared by a specific process. This process involves the formation of a mask by depositing a material that forms the mask onto the body to be etched and choosing the mask material so that it does not substantially wet the surface of the body. The mask thus fabricated has hill-type formations where the spacings between these formations are of the order of the wavelength of visible light. An etchant that etches the mask at a specific rate relative to the underlying body is then used to perform the etching procedure. Exemplary bodies produced by the procedure include tungsten textured bodies that exhibit light emissivities significantly higher than those possessed by the corresponding untreated tungsten material.

Selectively etched bodies

Materials have been made that exhibit high absorption in the visible, near ultraviolet, and near infrared spectral region while simultaneously exhibiting low absorptivity in the thermal infrared. Exemplary of such materials is silicon which is etched in a reactive sputtering process in the presence of a sputterable material. Other materials exhibiting useful properties are produced by this method.

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Fair Haven, NJ, United States of America

Harold G Craighead