Geodetic apparatus with laser source

Geodetic unit (1), especially a total station or distance meter, has a laser light source with at least a radiation producing laser diode (2b). The latter has an external cavity with at least a mono-selective component (2d) for selection of a single mode characteristic or monochromatic laser radiation. The selective component can be a linear emitter or a vertical semiconductor emitter driven by an external cavity in which there is a mono-selective component, e.g. a monomode fiber or resonating mirror that results in a mono-selective resonance effect. To compensate the longer pulse duration caused by the elongated cavity, components with negative dispersion can be used for pulse compression.