The optical property measurement of the mixture of methanol and ethanol based on laser interferometer

This study develops a high precision non destructive measurement technique based on a laser interferometer for determining the mixture of methanol and ethanol from its refractive index. The optical metrology system is employed to measure the refractive indexes of mixture sample with known methanol and ethanol. The ratio set of the mixture sample have seven sets. The refractive index of the ethanol solution with the methanol alcohol is reduced. When the mixture solution includes the methanol and ethanol, the refractive index of the mixture solution is between the refractive index of the ethanol and methanol. When the refractive index of the solution is very close the refractive index of the ethanol alcohol, the effect of the mixture solution in refractive index is very small. From this experimental result, the effect of the refractive index of the mixture solution in the refractive index of the ingredient liquid is very clear.