Abstract-High-pressure cell for terahertz time-domain spectroscopy

Wei Zhang, Daniel Nickel, and Daniel Mittleman
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-3-2983

We introduce a sample cell that can be used for pressure-dependent terahertz time-domain spectroscopy. Compared with traditional far-IR spectroscopy with a diamond anvil cell, the larger aperture permits measurements down to much lower frequencies as low as 3.3 cm−1 (0.1 THz), giving access to new spectroscopic results. The pressure tuning range reaches up to 34.4 MPa, while the temperature range is from 100 to 473 K. With this large range of tuning parameters, we are able to map out phase diagrams of materials based on their THz spectrum, as well as to track the changing of the THz spectrum within a single phase as a function of temperature and pressure. Pressure-dependent THz-TDS results for nitrogen and R-camphor are shown as an example.

© 2017 Optical Society of America

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Abstract-High-Q terahertz Fano resonance with extraordinary transmission in concentric ring apertures

Jie Shu, Weilu Gao, Kimberly Reichel, Daniel Nickel, Jason Dominguez, Igal Brener, Daniel M. Mittleman, and Qianfan Xu  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-4-3747

Optics Express, Vol. 22, Issue 4, pp. 3747-3753 (2014)

We experimentally demonstrate a polarization-independent terahertz Fano resonance with extraordinary transmission when light passes through two concentric subwavelength ring apertures in the metal film. The Fano resonance is enabled by the coupling between a high-Q dark mode and a low-Q bright mode. We find the Q factor of the dark mode ranges from 23 to 40, which is 3~6 times higher than Q of bright mode. We show the Fano resonance can be tuned by varying the geometry and dimension of the structures. We also demonstrate a polarization dependent Fano resonance in a modified structure of concentric ring apertures.

© 2014 Optical Society of America