Abstract: A real-time two-color laser speckle-shift strain-measurement system based on the technique of Yamaguchi is utilized to detect 1D strain in small diameter structural fibers. These measurements were performed using the dual-wavelength light output from an Argon Ion laser as the light source, coupled into two separate single-mode optical patchcords. The output of each optical patchcord is incident on the test specimen experiencing strain. This structural fiber is pulled in one direction while shifting speckle patterns reflected off the fiber are detected and strain is calculated in real-time (up to 150 frames/second). Two linear CCD arrays detect the speckle pattern with image processing performed by a hardware correlator. The strain resolution of this device is 20 $mu$epsilon@. Measurements were obtained at room temperature and attempts were made at elevated temperatures. This system is designed to be compact and robust and does not require surface preparation of the structural fibers. !13
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