Abstract: Disclosed herein is a particular type of fiber-optic, high-speed, balanced detector array designed to have very low artifacts, compact design, and low cost. The design is easily expandable to multiple channels of individual or detector pairs and the addition of transimpedance amplifiers to amplify the detected optical signals. The bandwidth of these devices is currently in the range up to 10 GHz with higher speeds being conceivable.

Abstract: A semiconductor p-i-n photodiode having a substrate, an n layer coupled to the surface of said substrate, an i layer coupled to the surface of said n layer, and a carbon doped p layer coupled to the surface of said i layer.

Abstract: An image of an object embedded in a diffusing medium is formed by propagating a coherent or equivalent light pulse through the diffusing medium and applying a reference pulse so as to gate precisely the first emerging light transmitted through the diffusing medium. An ultra-short pulse, having a duration on the order of 150 fs, insures that only the first emerging light is used to form a hologram. Instability in the diffusing medium, which may be inherent therein, as is the case with living tissue, or artificially induced therein, such as by vibrating the specimen, ensures that a subsequent hologram has a different background noise and speckle pattern. Integration of such holograms causes the background noise to average out, but time-invariant features, such as the object being imaged, become increasingly more visible as more holograms are integrated.

Abstract: The longitudinal electro-optic effect is used with an external probe to make voltage measurements on electrical conductors.

Abstract: Electrical signals are measured (analyzed and displayed) with subpicosecond resolution by electro-optic sampling of the signal in an electro-optic crystal, the index of which changes in response to the electric field produced by the signal, in accordance with the Pockels effect. The crystal is disposed adjacent to and in the fringe field of a line on a substrate, which may be part of an integrated circuit, for measuring signals propagating along the line during the operation of the circuit. A beam of short optical (laser) sampling pulses in the picosecond range is focused preferably close to the surface of the crystal and perpendicular to the optical axis of the crystal. The optical pulses transmitted through the crystal are processed to provide a display affording a measurement of the electrical signal.

Abstract: Electrical signals are measured (analyzed and displayed) with picosecond resolution by the electrooptic sampling of the signal being analyzed in a traveling wave Pockels cell. Sampling pulses, from an optical pulse generator such as a colliding pulse mode-locked laser, of subpicosecond duration are transmitted through the cell as polarized light and translated into a difference output corresponding to the difference in amplitude between the transmitted and rejected components of the polarized light. The signals, synchronous with the optical sampling pulses, are generated to propagate along the cell in a direction transverse to the transmission of the optical sampling pulses and in variably delayed relationship therewith. A separate beam of the optical pulses is desirably chopped and used to activate a photoconductive device which produces the signals.

Abstract: Electrical signals are measured (analyzed and displayed) with picosecond resolution and sensitivity in the microvolt (less than 100 microvolts) range by electron-optically sampling the signal. Sampling electron bursts are produced in response to a train of subpicosecond optical pulses. A beam of these electron bursts samples successive portions of the signal as it is transmitted as a travelling wave along deflection plates which act as a transmission line. The bursts are deflected in accordance with the amplitude of the successive portions of the signal and translated into spots of light, as on a phosphor screen. The deflection is significantly less than the diameter of the spot. The deviation of the spot with respect to the position thereof in the absence of the signal on the deflection plates is translated into a difference output. The signal to be analyzed is generated, synchronously with the optical pulses, to propagate along the deflection plates in variably delayed relationship therewith.