Abstract: The invention relates to a bar-type supporting structure for forming a frame, comprising a plurality of nodes and bars connecting the nodes, wherein each bar comprises at least one recess extending in the longitudinal direction of the bar, wherein the respective recess continues right into the node.

Abstract: The present invention is directed to a heterodyne interferometer arrangement with tunable laser light sources for absolute distance measurement. The phase angle changes which occur in the synthetic interference signals when varying the laser frequencies are recorded and evaluated. The arrangement also enables error-free distance measurement in the event of a change in the mathematical sign of the phase changes due to frequency jitter.

Abstract: An interferometer for absolute distance measurement with two lasers, one of which is tunable with respect to frequency. A device for collinear superposition of the laser beams is arranged downstream of the lasers. Further, interferometer units are provided whose optical path lengths differ from one another. An individual acousto-optical modulator (AOM) is arranged downstream of the device for superposing the beams. Light-conducting elements for guiding the beams are arranged between the AOM, between the AOM and at least one first beam splitter arranged downstream of the AOM, and between the light outputs of the first beam splitter and the light inputs of one or more interferometer units arranged downstream and/or within these interferometer units.