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24 September 1998 Interferometric translation-rotation encoder using diffraction gratings
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A new type of translation-rotation encoder using diffraction gratings is proposed and its advantages upon previously developed ones are pointed out. It makes use of two transparent dielectric gratings with the same groove spacing, each of them being joint to each of the moving parts whose relative displacement has to be detected and measured. The first grating is lighted under -1 order Littrow incidence, and the wavelength-to-groove spacing ratio is chosen in such a way that only 2 diffracted orders propagate both in reflection and transmission. The two transmitted orders fall on the second grating, and it is shown that they produce interference fringes with highest possible visibility in a large range of groove profile parameters and other experimental conditions. Thus this mounting allows producing high accuracy encoders by using cheap photoresist or plastic gratings, which opens the way to industrial applications in high-precision mechanics, information processing, etc.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michel Neviere, Evgueni K. Popov, B. Bojhkov, Lyubomir V. Tsonev, and Svetlen H. Tonchev "Interferometric translation-rotation encoder using diffraction gratings", Proc. SPIE 3450, Theory and Practice of Surface-Relief Diffraction Gratings: Synchrotron and Other Applications, (24 September 1998);

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