Abstract: A method is provided for fabricating thin membrane structures in localized surface regions of a single crystal substrate. In the method, ion implantation masks are patterned on the surface of the single crystal substrate with openings that define the localized surface regions. Foreign ions are implanted through the openings into the single crystal substrate to modify the chemical and/or structural properties of subsurface layers at predetermined depths underneath super layers of material. These subsurface layers are removed by selective etching. The removal of the subsurface layers leaves the super layers of material intact as membrane structures on top of openings or channels corresponding to the space of the removed subsurface layers. At least one portion or end of a membrane structure remains attached to the single crystal substrate.

Abstract: The Multimode Interference coupler according to the invention has smoothly continuous inwardly tapered sidewalls (301) which define the width of the multimode region (W1) along the propagation axis of the device. The inward taper causes the average width of the device to be reduced in comparison to known couplers having straight sidewalls (202). Further, invention allows the access waveguides (303, 309) to remain sufficiently spaced, while reducing the overall length of the device, to avoid lithographic gap fill-in and unwanted optical coupling between the waveguides.

Abstract: A method for fabricating ultra-thin single-crystal metal oxide wave retarder plates, such as a zeroth-order X-cut single-crystal LiNbO3 half-wave plate, comprises ion implanting a bulk birefringent metal oxide crystal at normal incidence through a planar major surface thereof to form a damage layer at a predetermined distance d below the planar major surface, and detaching a single-crystal wave retarder plate from the bulk crystal by either chemically etching away the damage layer or by subjecting the bulk crystal having the damage layer to a rapid temperature increase to effect thermally induced snap-off detachment of the wave retarder plate. The detached wave retarder plate has a predetermined thickness d dependent on the ion implantation energy.

Abstract: A method is provided for detaching a single-crystal film from an epilayer/substrate or bulk crystal structure. The method includes the steps of implanting ions into the crystal structure to form a damage layer within the crystal structure at an implantation depth below a top surface of the crystal structure, and chemically etching the damage layer to effect detachment the single-crystal film from the crystal structure. The thin film may be detached by subjecting the crystal structure with the ion implanted damage layer to a rapid temperature increase without chemical etching. The method of the present invention is especially useful for detaching single-crystal metal oxide films from metal oxide crystal structures. Methods for enhancing the crystal slicing etch-rate are also disclosed.

Abstract: A method is provided for detaching a single-crystal film from an epilayer/substrate or bulk crystal structure. The method includes the steps of implanting ions into the crystal structure to form a damage layer within the crystal structure at an implantation depth below a top surface of the crystal structure, and chemically etching the damage layer to effect detachment the single-crystal film from the crystal structure. The thin film may be detached by subjecting the crystal structure with the ion implanted damage layer to a rapid temperature increase without chemical etching. The method of the present invention is especially useful for detaching single-crystal metal oxide films from metal oxide crystal structures. Methods for enhancing the crystal slicing etch-rate are also disclosed.

Abstract: A method is provided for detaching a single-crystal film from an epilayer/substrate or bulk crystal structure. The method includes the steps of implanting ions into the crystal structure to form a damage layer within the crystal structure at an implantation depth below a top surface of the crystal structure, and chemically etching the damage layer to effect detachment the single-crystal film from the crystal structure. The method of the present invention is especially useful for detaching single-crystal metal oxide films from metal oxide crystal structures.

Abstract: The sensitivity of localized photochemical etching to the optical and electrical properties of multilayered semiconductor materials is utilized for selectively etching a laterally extending undercut in a buried layer. The semiconductor body is immersed in a suitable etching solution and a beam of light of appropriate wavelength and intensity is directed onto the semiconductor solution interface. The buried layer has a longer diffusion length for photogenerated carriers than the layers adjacent thereto, casuing carriers to diffuse away from the illuminated region within the buried layer and thereby etch the buried layer laterally, undercutting the adjacent layers.

Abstract: An integrated fiber optic coupler useful for the optical transmission of data from a light source to a detector located on a semiconductor chip which comprises a semiconductor wafer with a cavity etched into a surface, means wthin the cavity for converting light into an electrical signal, an electroconductive metal deposited on the surface of the semiconductor wafer around the opening of the cavity forming an electrical connection between the means for converting light into an electrical signal and circuitry etched into the wafer and an optical fiber inserted into the cavity and affixed to the semiconductor wafer.

Abstract: Isotopes are separated from an isotopically mixed molecular dopant dissolved in a cryogenic liquid. The solution is exposed to infrared laser light in order to selectively vibrationally excite a particular molecular species which contains the isotope or isotopes that are to be separated. The excited species then is reacted or dissociated to form recoverable reaction products rich in the isotope desired.