• Photoelastic constants of diamond

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/seca/025/02/0208-0219

    • Keywords

       

      Path Difference; Sylvine; Vibration Direction; Biaxial Crystal; Relative Retardation

    • Abstract

       

      All the photoelastic constants of diamond have been determined for the first time. The three stress-optic coefficients areq11=4·2×10−11,q12=−3·6×10−11,q44=2·6×10−11, from which the elasto-optic coefficients have been deduced to bep11=0·125,p12=−0·325,p44=0·11. It is found thatq11q12 andq44 are both positive and also that the refractive index of the crystal should decrease when subjected to a hydrostatic pressure, both of which are unique for diamond among the cubic crystals studied so far. In the course of the investigation, a new technique has been developed for determining the absolute path retardation, based on the production of localised interference fringes by the light coming from the two surfaces of the crystal.

    • Author Affiliations

       

      G N Ramachandran1

      1. Department of Physics, Indian Institute of Science, Bangalore
    • Dates

       
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