Abstract: A method for brazing together two parts at least one of which comprises a titanium aluminide material is described wherein a metallic layer of foil or powder is inserted between the parts in laminar contact with respective confronting surfaces thereof to be joined, the metallic layer comprising a metal which forms with titanium a eutectic composition having a characteristic fusion temperature lower than the fusion temperature of the metal, and the metallic layer and confronting surfaces of the parts are heated to a temperature of about the characteristic fusion temperature of the eutectic composition.

Abstract: High total transmission, tunable comb filter structures are described which comprise moderately thick layers of optical material having periodic or multiply periodic refractive index modulation features comprising a multiplicity of coherently-coupled, weakly-resonant optical cavities, resulting in and characterized by spectra of high order (5 or higher) relative to a fundamental (lowest order) cavity resonance, consisting of narrow, moderate to high density reflection lines occurring in one or more sets, each set being characterized by lines equally spaced by wave number if optical dispersion is neglected. Filters of the inversion can be structured to be tuned, electro-optiRIGHTS OF THE GOVERNMENTThe invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.

Abstract: A single crystal bender actuator for selectively positioning a movable precision optical or acoustical component is described which comprises a single crystal of barium titanate, barium strontium titanate, barium lead titanate, potassium niobate tantalate, lead titanate-lead magnesium niobate or other material in which a special domain structure can be induced to produce a very high strain bimorph configuration, the single crystal operatively interconnecting support structure and the movable component, and means for selectively applying an electric field of controllable field strength to the crystal.