Measurement of thickness and refractive index using femtosecond and terahertz pulses

摘要

We report a simple method to measure the thickness and refractive index of parallel-plane samples simultaneously using femtosecond and terahertz pulses. The time-of-flight measurements of the pulses with and without a sample are exploited to determine the thickness and refractive index of the sample. The accuracy in thickness measurement using femtosecond pulses is 2-3 μm where refractive index can be measured with an accuracy up to three decimal points. The accuracy and lower limit of thickness measurement using terahertz pulses is also improved.