Abstract: A folded slab waveguide laser having a hybrid waveguide-unstable resonator cavity. Multiple slab waveguides of thickness ‘t’ supporting vertical waveguide modes are physically arranged above one another in a stack and optically arranged in series through one or more cavity folding assemblies with curved mirrors. A gain medium such as a gas is arranged in each slab. Each cavity folding assembly is designed to redirect the radiation beam emitted from one slab waveguide into the next waveguide and also at the same time to provide a focus for the radiation beam so that a selected vertical waveguide mode (or modes) is (or are) coupled efficiently into the next slab.

Abstract: An impact-reinforced piezocomposite transducer array comprises a load supporting structure having a plurality of cells, each of said cells comprises a piezocomposite transducer element. The load supporting structure comprises a honeycomb structure having a plurality of multi-sided cells or the structure comprises a plurality of cylindrical cells. The piezocomposite element includes a plurality of piezoceramic rods encapsulated in a polymeric matrix to form a 1-3 composite body. The transducer array may be used as a hydrophone or a transmitter in a rugged environment such as on the hull of an icebreaker ship.

Abstract: A roller transducer assembly comprises at least one core section and each core section comprises a transducer. Oil is retained within the roller transducer assembly and in particular an oil kerf isolates each core section from an outer portion of the roller transducer assembly having a nylon roller tube which is surrounded by a urethane tire outer covering. The outer portion of the roller transducer assembly rotates about each stationary core section. A pair of the ultrasonic roller transducer assemblies are arranged to provide signals for generating an ultrasonic image of an article such as a board or a log passing between the pair of ultrasonic roller transducer assemblies.

Abstract: A piezoelectric acoustic sensor including stress-transferring arches to protect the elements at the lateral side surfaces. An array of parallel rod-like or blade-shaped elements is formed from a dense, poled, strongly piezoelectric or electrostrictive ceramic material. The array is encapsulated in a matrix, e.g., a polymeric matrix, to form a two-phase ceramic/polymer composite body exhibiting 1-3 or 2-2 connectivity. The upper and lower ends of the elements are exposed at upper and lower planar surfaces of the composite body to electrically contact upper and lower electrodes. A stiff portion, e.g., a face plate, extends across each of the upper and lower electroded surfaces, each extending to the edge surfaces of the composite body. A convex-shaped, stress-transferring arch is rigidly anchored to at least one edge of each stiff portion. Hinge portions of each arch at the edges of the stiff portions has a thickness of 0-10 mm.