Rotation method for the measurement of thickness of $Z$-cut uniaxial crystals

An original polarization method for the measurement of thickness of $Z$-cut uniaxial crystals employs the transmittance measurement of the polarizer–crystal–analyzer system at different rotation angles of the crystal. The mathematical analysis of the method is based on the optics of uniaxial crystals and Jones matrices. A measurement error of no greater than $\pm$ 0.6 $\mu$m is estimated using the formula of a vector sum. $Z$-cut crystals of congruent lithium niobate with rated thicknesses of 514 and 554 $\mu$m are used to experimentally test the method and propose practical recommendations for applications.