Abstract: A radar ranging system uses a laser transmitter and a single detector for producing the start and stop signals for the time interval measurement. Two reference signals are produced by passing two light portions, decoupled from the laser light to be transmitted to a target, through two different delay lines to the detector. The time difference between the first reference signal and a target signal is a measure for the range to be measured. The time difference between the two reference signals is used as a calibration measure for repeatedly calibrating the system. The true range is calculated by forming the ratio of the two time intervals.

Abstract: A laser such as a wave-guide laser with its housing is encased in a second housing which is also filled with laser gas. The second housing is sealed in a gas tight manner and includes a cylindrical portion, which may be made of metal, and a cap made at least partially of glass or ceramic. The cap is provided with a neck around the laser beam passage. The neck has a rated or predetermined break strength to make sure that a portion of the cap will break off at the neck when the laser is operated. The cap is provided with a device for monitoring or checking the operation status of the laser. The checking device includes a bellows, the interior of which is connected to sense the pressure inside the second housing. Further indicators showing whether the laser is operating are also provided in the cap which breaks off automatically with the aid of the bellows when the latter expands in response to a perforation of the cap by the initial laser operation.

Abstract: A CO.sub.2 laser wave guide, which is excitable by a high frequency signal, as two boron nitride bodies (11a, 11b; 111a, 111b) which are held in position in a housing (10) by a specially shaped spring (14, 114) which presses the boron nitride bodies against the inner surface (10a) of the housing for good heat transfer and dissipation. A spacer (18) holds the boron nitride bodies apart to provide a gap (15) in which one electrode is held. The specially shaped spring operates, in addition to holding the boron nitride bodies in place, as the opposite electrode. This structure requires few parts and these parts do not have to meet high tolerance requirements, nor is it necessary to provide a high surface finish for the individual components.