Wedge cells for refractometry: materials and parameters selection criteria

Abstract

This work presents the materials and parameters selection criteria of wedge cells for refractometry in the visible range. These cells consist of two right angle prisms facing each other, defining a wedge-shaped cavity where the sample is placed. The refractive index of the sample is determined from the deviation of a light beam that traverses the cell. This model for engineering purposes includes the cell geometry and the refractive indexes of the cell material and the sample. We perform the numerical calculation and ray tracing of the optical system. We also propose polinomial fitting functions in order to simplify the numerical treatment, and as a complement to the complete set of equations. These polynomials give the refractive index of the sample as an explicit function of the deviation angle. An analysis of the approximation errors is also given.

Keywords

• instrumentación óptica, refractometría, metrología