Abstract: A laser source provides a pulse that is subdivided and replicated into subpulses by a delay structure having a plurality of steps. Each of the subpulses is delayed by one of the plurality of steps and the amount that each subpulse is delayed is different than the others with respect to the pulse. The amount of each delay, and the consequent time delay produced, is greater than the duration of the pulse, which minimizes overlap between adjacent subpulses. The pulse may be transmitted through the delay structure or it may be reflected from the delay structure. Repetition rates of up to hundreds of THz or greater are achieved, and the system and method may be used in Time Division Multiplexing Systems. Information may be transmitted and carried by the subpulses by appropriate modulation techniques.

Abstract: A laser source provides a pulse that is subdivided and replicated into subpulses by a delay structure having a plurality of steps. Each of the subpulses is delayed by one of the plurality of steps and the amount that each subpulse is delayed is different than the others with respect to the pulse. The amount of each delay, and the consequent time delay produced, is greater than the duration of the pulse, which minimizes overlap between adjacent subpulses. The pulse may be transmitted through the delay structure or it may be reflected from the delay structure. Repetition rates of up to hundreds of THz or greater are achieved, and the system and method may be used in Time Division Multiplexing Systems. Information may be transmitted and carried by the subpulses by appropriate modulation techniques.

Abstract: A passive ranging system measured spectra of solar radiation off an adjacent spot and a distal target. Reflected solar radiation and differential attenuation are used to estimate target range. A comparison of absorption spectra from the solar illuminated distal target compared to the adjacent location is performed. Since the sun's position is always known, the increased absorption due to a distant target is derived from the differential between the adjacent spot and the distal target.

Abstract: A passive ranging optical system is coupled to an active radar system. The passive ranging optical system provides range and rate information to the active radar system. After receiving the range and rate information, the active radar system uses fewer transmission pulses but achieves higher resolution of the range of the target because of improved range gate information.

Abstract: A system and method of passive ranging for a luminous target which employs a prior knowledge of atmospheric attenuation of spectral frequencies to determine range by comparing the intensities of a frequency component, that is attenuated by propagation through the atmosphere, with a frequency component that is not.

Abstract: Multiple independent spectral measurements of light reflected from a target are produced concurrently by illuminating the target with a train of laser pulses wherein the train of pulses produces a line spectrum within the illuminating signal. A characteristic dimension of the receiving aperture is established based on illuminating wavelength, a cross-sectional dimension of illuminated region of a target, and the range between a target and the receiving aperture or image plane. The characteristic dimension corresponds to the spacing of peaks in a speckle pattern of an image plane. The use of multiple receiving telescopes having the characteristic dimension allows for independent measurements concurrently by each of the receiving telescopes. The train of illuminating pulses is generated by mode-locked operation of the laser for synchronization of sinusoidal components at line frequencies of the pulse train spectrum, and wherein the spacing of the spectral lines is at least a decorrelation frequency.

Abstract: A system and method of passive ranging for a luminous target employs a prior knowledge and a present measurement of its electromagnetic spectrum during a target acquisition procedure and, subsequently, during analysis of the spectrum to determine the effects of atmospheric attenuation on various parts of the spectrum. Relative attenuation of various spectral components by the atmosphere is indicative of target range.

Abstract: A system and method of passive detection of a luminous target employs a prior knowledge and a present measurement of its electromagnetic spectrum during a target acquisition procedure and, subsequently, during analysis of the spectrum to determine the presence of Doppler shift and broadening of lines of the spectrum. The prior known reference spectrum is adjusted for the Doppler shift so as to enable identification of the corresponding spectral lines of the received target spectrum. A history of the spectral data enables an identification of the type of target, as in the case of a rocket, and a determination of characteristics of a flight of the rocket.

Abstract: A high pressure self-sustained gas laser operating at a high specific energy loading and long pulselength. The laser comprises an endless duct for circulating a laser generating gaseous medium and two discharge electrodes for exciting the molecules of the gaseous medium. Behind the discharge cathode electrode is an electron-beam transmitter for transmitting a beam of preionizing electrons into the gaseous medium to preionize the region near the cathode discharge electrode. The region unpreionized by the electron beam is ionized by drifting electrons from the cathode region and avalanche ionization. The applied discharge voltage never exceeds the glow voltage allowing low discharge flush factors under repetitive operation with flowing laser gas.

Abstract: This invention provides a laser or high voltage switch which has two spaced apart main discharge electrodes which define between them a main discharge gap, a discharge inducing member that is of an insulating material and which provides a planar or curved trigger discharge surface adjacent the electrodes and partially or completely bridging the main discharge gap, and an auxiliary conductor on the other side of the discharge inducing member to the main discharge electrodes and capacitively coupled to one of them by a distributed stray capacitance, such that when an excitation pulse is applied across the main discharge electrodes an initial capacitively initiated low order trigger discharge occurs onto the trigger discharge surface, and preferably across the surface from one main discharge electrode to the other. This trigger discharge photo-ionises a gas in the main discharge gap to cause a glow discharge between the main electrodes.

Abstract: This invention provides a transversely excited travelling-wave gas laser in which the excitation pulse is shaped by a pair of elongate electrodes, the separation of which varies along their length. The separation is ideally determined empirically. Preferably, the laser has a pair of main discharge electrodes having a constant separation between which the lasing discharge occurs, and a pair of timing electrodes electrically in series with the main discharge electrodes, the separation of which varies such that the discharge between the timing electrodes provides a sharpened pulse that arrives along the main electrodes in such a manner as to obtain a travelling wave laser discharge. The main and timing electrodes are preferably segmented. The separation of the electrodes is determined empirically by bringing successive portions of the main discharge electrodes into alignment and varying the separation of corresponding portions of the timing electrodes to obtain the required timing characteristics.