Abstract-Characterization of Thin Metal Films Using Terahertz Spectroscopy

 Zhiyong Wang,  Yunhui Han, Xu, Lin Chen,  Chuanwei Li,  Liang Wu, Weili Zhang,

http://ieeexplore.ieee.org/document/8254401/

A theoretical model is presented to simulate the transmission of thin metal films. Using terahertz spectroscopy, the two key characteristic parameters, conductivity and thickness, are determined simultaneously by fitting the experimental data to the theoretical model. Three different metal films, aluminum, copper, and silver, are investigated. The measured conductivities are significantly less than the bulk values. The sample thicknesses obtained are consistent with those estimated by the quartz thickness monitor.

United States Patent 9508610-Inline measurement of molding material thickness using terahertz reflectance

United States Patent 9508610
Inventors:
Liu, Shuhong (Chandler, AZ, US) 
Ghosh, Nilanjan Z. (Chandler, AZ, US) 
Wang, Zhiyong (Chandler, AZ, US) 
Goyal, Deepak (Phoenix, AZ, US) 
Gokhale, Shripad (Gilbert, AZ, US) 
Zhang, Jieping (Chandler, AZ, US)

http://www.freepatentsonline.com/9508610.html

A method including emitting a terahertz beam from a light source at a layer of molding material; detecting a reflectance of the beam; and determining a thickness of the layer of molding material. A system including a panel supporter operable to support a panel including a plurality of substrates arranged in a planar array; a light source operable to emit a terahertz beam at a panel on the panel supporter; a detector operable to detect a reflection of a terahertz beam emitted at a panel; and a processor operable to determine a thickness of a material on the panel based on a time delay for an emitted terahertz beam to be detected by the detector.

Abstract-Metamaterials: A New Ba0.6Sr0.4TiO3–Silicon Hybrid Metamaterial Device in Terahertz Regime

http://onlinelibrary.wiley.com/doi/10.1002/smll.201670098/full

A giant terahertz modulation based on a Ba0.6Sr0.4TiO3–silicon hybrid metamaterial is reported by L. Wu, W. Zhang, and co-workers on page 2610. The proposed nanoscale Ba0.6Sr0.4TiO3 (BST) hybrid metamaterial, delivering a transmission contrast of up to ≈79% due to electrically enabled carrier transport between the ferroelectric thin film and silicon substrate, is promising in developing high-performance real world photonic devices for terahertz technology.

Abstract-A New Ba0.6Sr0.4TiO3–Silicon Hybrid Metamaterial Device in Terahertz Regime

http://onlinelibrary.wiley.com/doi/10.1002/smll.201600276/full

Metamaterials, offering unprecedented functionalities to manipulate electromagnetic waves, have become a research hotspot in recent years. Through the incorporation of active media, the exotic electromagnetic behavior of metamaterials can be dramatically empowered by dynamic control. Many ferroelectric materials such as BaSrTiO3 (abbreviated as BST), exhibiting strong response to external electric field, hold great promise in both microwave and terahertz tunable devices. A new active Ba0.6Sr0.4TiO3–silicon hybrid metamaterial device, namely, a SRR (square split-ring resonator)–BaSrTiO3 thin film-silicon three-layer structure is fabricated and intensively studied. The active Ba0.6Sr0.4TiO3 thin film hybrid metamaterial, with nanoscale thickness, delivers a transmission contrast up to ≈79% due to electrically enabled carrier transport between the ferroelectric thin film and silicon substrate. This work has significantly increased the low modulation rate of ferroelectric based devices in terahertz range, a major problem in this field remaining unresolved for many years. The proposed BST metamaterial is promising in developing high-performance real world photonic devices for terahertz technology.