Refractive index measurement of the glass substrate of holographic plates using reflectivity data

A simple method to measure the refractive index of plane parallel glass pla tes using reflectivity data is presented. The method is based on the analys is of Fresnel reflections which take place on the air-glass surfaces of the plate. One of these reflections is eliminated by using a black self-adhesi ve PVC masking tape on the back of the plate. The excellent agreement betwe en calculated and measured data confirms the applicability of the method.