A method of measuring the refractive index of extraordinary ray in uniaxial crystal with optic axis at an arbitrary orientation

<正>A new equation to measure the refractive index of extraordinary ray in uniaxial crystal with the optic axis at an arbitrary orientation has been given in this letter,and the term in this equation makes the measurements to be relatively easy.The theoretical study shows that the accuracy achieved in the experiments attains to the order of magnitude in 10-3.