Carl-zeiss-stiftung

Alexander Hinz

Franz Krug

Harald Volkenandt

Wolfgang Rupp

A gas laser 1 such as a .sup.13 CO.sub.2 -laser emits at two different wavelengths (.lambda..sub.1, .lambda..sub.2) with a sine-shaped adjustment of a resonator mirror or a grating 13 such as a Littrow grating. The gas laser emits radiation at the two desired wavelengths (.lambda..sub.1, .lambda..sub.2) in two mutually adjacent intervals of the resonator length L because of a suitable dimensioning of the grating 13 with respect to grating structure and angle position, the outcoupling factor of the outcoupling mirror 12, the resonator length L and the composition of the gas of the laser. The laser emission is inhibited at the crossover between the two intervals and the sine-shaped modulation (for example with a piezo element) of the resonator length L is essentially symmetrical about this crossover. The invention is also directed to an arrangement for detecting a substance such as NH.sub.3 in a flue gas. This arrangement includes a two wavelengths laser light source 1, a modulation unit 14 and a reference detection unit D1; a transmission optic 2; a measuring path 3 which contains the substance to be detected; a receiving optic 4 and a measuring detector D2. An evaluation apparatus 5 is also provided which determines the ratio of the light absorption in the measuring path 3 at the two wavelengths (.lambda..sub.1, .lambda..sub.2) and determines therefrom the concentration of the substance to be detected in the measuring path 3.

Gas laser for emitting light modulated at two different wavelengths and

The invention is directed to a laser radar method for measuring velocity of moving objects wherein the laser light reflected from the measured object is coupled back into the laser resonator and then conducted to a heterodyne receiver. An amplification effect is produced by the interaction of the reflected signal with the laser active medium and the resonator and this amplification effect produces an improved signal/noise-ratio and makes possible a simpler configuration of the measuring arrangement.

Laser radar system

The invention is directed to a highly stable CO.sub.2 waveguide laser wherein a resonator block is used which is made of a material having a low thermal expansion coefficient. The resonator block includes a window which is transparent for the wavelength of the laser. Laser reflectors are provided which are mounted by wringing to the resonator body and define a vacuum-tight seal of the resonator body. In this way, the resonator block has a permanently defined adjustment.

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Konigsbronn, Germany

Alexander Hinz