A thorium oxide-free B.sub.2 O.sub.3 --La.sub.2 O.sub.3 --Gd.sub.2 O.sub.3 --Ta.sub.2 O.sub.5 system optical glass is improved in stability to devitrification and in optical constants by introducing at least one of a divalent metal oxide such as ZnO, CdO, PbO, BaO, SrO, CaO, and MgO into the optical glass composition or replacing Ta.sub.2 O.sub.5 of the optical glass composition with a divalent metal oxide. If desired, the glass may be free of CdO.

An optical switch comprises a substrate having a first refractive index and upporting electro-optic material having a second higher refractive index and defining waveguides which diverge into at least two spatially separated paths. A pair of electrodes is positioned proximate each of the spatially separated paths and when a source of electrical energy is applied to a selected pair of electrodes, an electric field is created across the associated spatially separated path which substantially lower...

An optical pantograph for directing light beams and the like from a source to a receiver according to the movement of a pointer. The device can be used for, among other things, directing a laser beam and the like to a target for etching patterns on a target according to the movement of a pointer relative to a pattern trace.

Optical wedge filter comprising a coloured gelatine layer on a flexible transparent support and a flexible transparent covering foil bonded the gelatine layer wherein the thickness of the coloured gelatine layer increases stepwise or continuously.

A diffractometer of the type comprising a light source, an image transformation unit and an image reconstruction unit, in which the image transformation unit includes a condenser lens, is provided with an adjustable aperture stop in the focal plane of the condenser lens. A further adjustable aperture stop may be provided at the entrance pupil of a collimating lens of the image transformation unit. A television camera is positioned to receive light from the diffractometer and a further lens is us...

An optical metronome with a transparent continuous belt carrying vertical markings carried between rollers, supported between rigid transparent plates, and passing behind a translucent sheet of music through which the vertical markings are viewed. The lighting behind the belt is from horizontally extending tube type lamps and reflectors, or flat faced neon lamps which form one of said rigid transparent supporting plates with their flat faces.

In a preferred embodiment, a two-electrode discharge device, or "optical multipactor," for modulation of high-power radiation beams, especially adapted for switching or attenuating laser beams; the device providing an inter-electrode gap with electron cloud oscillating thereacross, operating as secondary electron emission in resonance mode with the passing beam. This device is capable of providing much faster beam switching, wider modulation bandwidths and extremely low capacitance, such that it...

A filter light source within a compound optical filter includes a flat sheet consisting of a plurality of fine particles of a phosphor in a transparent matrix having refractive index greater than thaat of air but less than that of the particles. To measure the absorbance of light by a fluid, light that has passed from a primary light source through the fluid is transmitted by an interference filter in the compound filter to the filter light source. The phosphor has a high excitation efficiency a...

A quick-disconnect coupler for a light-transmitting flowcell having in a sight path light-input and light-output windows, respectively, for interposition intermediate a light source and a light detector, respectively, at least in part through a pair of elongated light-transmitting elements, and a support member for the flowcell. There is provided a slip-on flowcell supported on the support member, and a quick-release clamp comprising a pair of jaw members having a pair of corresponding end porti...

An optical system in which a screened light pattern and a light image of an original document are projected onto a common region of a light receiving member forming a modulated light image thereon. Collimated light rays are employed in the formation of the screened light pattern.