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Title: Diffraction encoded position measuring apparatus

When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.
  1. (Thousand Oaks, CA)
Publication Date:
OSTI Identifier:
Report Number(s):
US 5050993
DOE Contract Number:
Resource Type:
Research Org:
Rockwell International Corp
Country of Publication:
United States
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