Abstract: A device for expanding a laser beam into an extremely wide diffraction arc is described. The expander consists of an array of multiple optically transparent fibers of a first diameter alternating with fibers of one or more diameters different from said first diameter arranged in parallel and in a single plane. A laser beam incident on the array is transmitted therethrough and expanded into an extremely wide diffraction arc of almost 180 degrees. Also disclosed is a laser beam profile converter capable of transforming a laser beam having a Gaussian profile into a beam with a substantially uniform intensity distribution, or a predetermined intensity distribution, along the entire length of diffraction arc. The converter comprises multiple optically transparent fibers of the same diameter arranged in a single array, or a rectangular array. At the input end of the converter, the fibers are arranged in one or more uniform layers.

Abstract: A liquid level gauge for tanks and other liquid holding receptacles, having a pressure sensing chamber which is partially enclosed by a flexible diaphragm and which is communicated with a pressurized medium. Pressure control means cooperative with said chamber, is communicated therewith together with a switching means to neutralize the deflection of the diaphragm which is normally caused by liquid in the tank.