Abstract: A directionally solidified, optically conductive eutectic system and method of forming the same. A Type II eutectic which divides into fiber and matrix phases when directionally solidified consists of a fiber phase having a lesser molecular weight but higher refractive index than the matrix phase. The resulting fiber array is optically conductive, and may be used to advantage in applications such as CRT screens, waveguides, fiber optic image intensifiers, and lasers.

Abstract: A cathode device which employs regenerative ion feedback for sustained electron emission includes an enclosure filled with inert gas. A cathode, an electron multiplier region, and an ion interaction region are disposed in consecutive order within the enclosure with the interaction region being positioned at the output of the electron multiplier region. Means are provided for controlling the magnitude of ion feedback to the cathode whereby the feedback loop gain of the device can be caused to be either greater than, or less than, unity. The cathode device is useful in a cathodoluminescent cell which further includes an electron accelerating region and a cathodoluminescent screen. A plurality of these cathodoluminescent cells can be arranged so as to constitute an image display device. Disclosed also is a method of operating the cathode device and image display device.