Abstract
We present the potential of an antireflection self-reference method based on ultra-thin tantalum nitride (TaN) nanofilms for improving terahertz (THz) reflection spectroscopy. The antireflection self-reference method is proposed to eliminate mutual interference caused by unwanted reflections, which significantly interferes with the important reflection from the actual sample in THz reflection measurement. The antireflection self-reference model was investigated using a wave-impedance matching approach, and the theoretical model was verified in experimental studies. We experimentally demonstrated this antireflection self-reference method can completely eliminate the effect of mutual interference, accurately recover the actual sample's reflection and improve THz reflection spectroscopy. Our method paves the way to implement a straightforward, accurate and efficient approach to investigate THz properties of the liquids and biological samples.
Highlights
Terahertz radiation lies between microwave and infrared radiation, which is within the frequency range for macromolecule's vibration and rotational frequencies
In the terahertz measurement of reflection geometry, the liquids and biological samples are typically placed on a substrate, which is made of materials with negligible absorption in the terahertz frequency range, such as high-resistivity silicon and z-cut quartz
This phenomenon was called mutual interference. It arises from the ring tail of the reference reflection from the lower surface of the substrate, which significantly interferes with the sample reflection from the upper surface of the substrate
Summary
Terahertz radiation lies between microwave and infrared radiation, which is within the frequency range for macromolecule's vibration and rotational frequencies. Various methods for the THz reflection measurement of liquids and biological samples was proposed, including the ATR(attenuated total reflectance) method [15], the sample baseline method [16] and the optical delay method based on a thicker substrate [13] These methods can partly reduce the effect of mutual interference but cannot completely eliminate the effect and have complicated measurement requirements, which restrict their practical applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
