Vandrevala Farah, Einarsson Erik
Opt Express. 2018 Jan 22;26(2):1697-1702. doi: 10.1364/OE.26.001697.
Terahertz time-domain spectroscopy (THz-TDS) relies heavily on knowing precisely the thickness or refractive index of a material. In practice, one of these values is assumed to be known, or their product is numerically optimized to converge on suitable values. Both approaches are prone to errors and may mask some real features or properties of the material being studied. To eliminate these errors, we use THz-TDS in reflection geometry to accurately and independently determine both thickness and refractive index by illuminating the step-edge of a substrate atop a metal stage. This method relies solely on the relative time delay among three reflected pulses, and therefore forgoes the need for optimization or assumption of substrate parameters.
太赫兹时域光谱（THz-TDS）在很大程度上依赖于精确知晓材料的厚度或折射率。在实际操作中，通常假定其中一个值是已知的，或者对它们的乘积进行数值优化以收敛到合适的值。这两种方法都容易出错，并且可能掩盖所研究材料的一些真实特征或特性。为了消除这些误差，我们在反射几何结构中使用太赫兹时域光谱，通过照射金属平台上衬底的台阶边缘来准确且独立地确定厚度和折射率。该方法仅依赖于三个反射脉冲之间的相对时间延迟，因此无需对衬底参数进行优化或假设。
