Accurate determination of terahertz optical constants by vector network analyzer of Fabry-Perot response

Abstract

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.38.005438. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.We present a method based on a Fabry-Perot model to efficiently and accurately estimate optical constants of wafer samples in transmission-only measurements performed by a vector network analyzer (VNA). The method is demonstrated on two separate wafer samples: one of silicon and the other of polymethylmethacrylate. Results show that the method can not only acquire optical constants accurately and simply over a broad frequency domain but also overcome the limitations of calculation for dispersive and lossy materials to which existing methods are susceptible, such as those based on VNA-driven quasi-optical transmissometers and terahertz time-domain spectrometry