2 March 1984 A Synthetic Aperture Phase Measurement System Using A Metering Rod Bridge With Corner Cubes
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A wavefront control concept has been developed for piston phase matching of an array of subaperture telescopes such as might be used as a pointer for laser power transmission or for an astronomical telescope. Deep within the optical system, an absolute distance inter-ferometer injects a diagnostic beam into the main beam train. The diagnostic beam is divided into smaller beams which propagate through the subaperture beam trains and exit out of the subaperture telescopes. A metering rod is placed so as to bridge the outgoing diagnostic beams from adjacent subaperture telescopes. If a series of small retro-reflecting corner cubes are attached to the metering rod, these retro-reflectors will return these wavefront samples back through the beam train to the absolute distance interferometer where the samples from one subaperture are compared indirectly to those from the adjacent subaperture through a common reference beam. The absolute distance interferometer is a two wavelength digital heterodyne interferometer. The absolute distance interferometer measures absolute phase, thus establishing the absolute optical path length (OPL) between the inter-ferometer and corner cubes. Differences in beam path are then adjusted to any required zero or non-zero value by optical trombones and an adaptive mirror incorporated in the beam path. Testing for colinearity of the reference corner cubes on the metering rod eliminates errors due to metering rod misalignment.
© (1984) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
K Sun, K Sun, T Waite, T Waite, K Kissell, K Kissell, F White, F White, } "A Synthetic Aperture Phase Measurement System Using A Metering Rod Bridge With Corner Cubes", Proc. SPIE 0440, Synthetic Aperture Systems I, (2 March 1984); doi: 10.1117/12.937570; https://doi.org/10.1117/12.937570


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