Abstract: An active waveguide device is provided for doubling the frequency of an applied light wave. The device includes first and second optical waveguides which are coupled through a separating gap. The coupling can be precisely adjusted to maximize the doubling efficiency by adjusting the gap dimension. The device is particularly suitable for producing higher frequency blue radiation from lower frequency infrared radiation which is readily produced by semiconductor lasers.

Abstract: A method for providing a curved composite ultrasound transducer of a relatively large size. A blank of piezoceramic material has its rear side reticulated with a series of relatively coarse grooves. The front side of the material is reticulated with a series of relatively deep fine grooves to provide a matrix of upstanding piezoceramic rods. The spaces between the rods on the front side of the blank are therefore filled with a curable polymeric resin (epoxy). The resin filling the blank spaces on the front side is partially cured. After partial curing, the blank is placed into a spherical compression mold and molded so that its front side is formed concave and its rear side convex. The resin is cured while holding the molded blank under pressure in the mold until the resin has cured. After curing, the blank is removed from the mold and the back side is ground away to provide a spherically curved transducer having a multiplicity of individual piezoceramic rods disposed in a matrix of cured resin.

Abstract: A Soller slit and method of producing a Soller slit by forming a plurality of grooves in two identical ceramic blocks. The two blocks are then bound together with parallel blades of each block facing each other. The ceramic blocks can contain lead titanate.