Compagnie Generale D'electricite

Compagnie Industrielle Des Lasers Cilas Alcatel

Agence Nationale De Valorisation De La Recherche (anvar)

Olivier De Witte

Bernard Lacour

Chantal Vannier

Marc Maillet

Pierre Dezauzier

Armand Eranian

Claude Jourdain

Philippe Rovati

An X-ray generator 7 directly connected to the electrode 8 internally of a hollow cathode 3 emits electrons under a field effect to generate X-rays, the generator 7 supplying 50 to 100 Kv with a rise time of less than 10 nanoseconds. X-rays rapidly created, in turn, rapidly create electrons in the active medium 1 between anode 2 and cathode 3 to trigger a discharge therebetween, across which anode and cathode the voltage of a laser capacitor is pre-applied at a level below the breakdown voltage of the active medium.

Gas laser excited by a transverse electrical discharge triggered by

Apparatus for the detection of an enemy infrared camera. This apparatus includes a continuous infrared laser 1 directed towards camera 25, a receiver 10 of the infrared signals sent by the camera, a processing circuit 23 of these signals, able to determine a delay time, a delay circuit 22 supplying electrical signals delayed by the said delay time in relation to the reception of infrared signals, and a pulsed laser 16 sending to camera 25 laser pulses respectively on reception of the delayed signals. The apparatus causes a very bright spot to be created on the camera screen which represents a picture of a dummy object displaced by a predetermined distance from the apparatus. This spot overshadows the spot on the screen corresponding to the true location of the apparatus. Application is for detection of an enemy infrared camera placed on a tank.

Apparatus for detection of an enemy's infrared camera

The laser comprises a gas-filled channel (51) extending between a pair of metal plates (2 and 3). The laser is excited by a spark discharge through the gas from one plate to the other. The energy for the spark comes form a pair of built-in capacitors extending between the plates on either side of the channel. The plates constitute the plates of the capacitors, and apart from a plastic retaining wall (37, 39) round each capacitor, the capacitor dielectric is water. The water is advantageously pumped (47) round a cooling circuit (48), and it is not permanently damaged if an accidental discharge takes place through the water. The invention is particularly applicable to nitrogen and to excimer lasers.

Capacitor discharge excited gas laser

A gas laser in which the gas is excited by laser discharge, said laser including two capacitors formed by two parallel metal plates (2, 3) between which two dielectric parts (4,5) are spaced apart to form a passage (6) which contains the laser gas. It further includes a transformer (13) whose secondary winding (12) is connected to the plates and whose primary winding (14) is connected in series with a capacitor (15), means (17) for charging and capacitor and a thyristor (16) for discharging the capacitor in the primary winding. Application to exciting gas lasers in which the gas contains a dye stuff.

Gas laser in which the gas is excited by capacitor discharge

A plurality of electrodes (7, 10) are arranged along two rows facing each other in pairs, leaving a spark gap in between the rows of electrodes. Each row comprises a plurality of electrodes connected in parallel. The electrodes are in a gas. The problem is to trigger simultaneous arcs between each pair of electrodes. This is achieved by extending an insulated conductor (15) parallel to the rows and then in applying pulses to the insulated conductor to obtain a corona discharge around it. The resulting ions suddenly reduce the striking potential across the spark gap. A potential difference is applied across the gap by a generator (12). The potential is below the nonionized striking potential and above the ionized striking potential. The sudden drop in striking potential ensures that all pairs of electrodes strike substantially simultaneously. The apparatus can be used to excite a high repetition rate gas laser generators.

Spark gap apparatus comprising a plurality of pairs of electrodes in

The laser comprises an amplifying medium which sustains the oscillation within two resonators, one resonator being formed by the mirrors M.sub.1 and M'.sub.1 and the other being formed by the mirrors M.sub.2 and M'.sub.2. The quality factor of the second resonator is higher than that of the first resonator. The time-duration of the pulse extracted from the first resonator is adjusted by modifying the quality factor of the second resonator. The double-resonator laser serves to generate pulses of very small width, especially in dye lasers, and to adjust pulse-widths in such applications as telemetry.

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Gif sur Yvette, France

Olivier De Witte