Abstract-Superconductivity Induced Transparency in Terahertz Metamaterials

Odeta Limaj , Flavio Giorgianni , Alessandra Di Gaspare , Valeria Giliberti , Gianluca De Marzi ,Pascale Roy , Michele Ortolani , Xiaoxing Xi , Daniel Cunnane , and Stefano Lupi

http://pubs.acs.org/doi/abs/10.1021/ph500104k?journalCode=apchd5

Plasmonic analogue of Electromagnetically Induced Transparency is activated and tuned in the terahertz (THz) range in asymmetric metamaterials fabricated out of high critical temperature (Tc) superconductor thin films. The asymmetric design provides a near-field coupling between a superradiant and a subradiant plasmonic mode, which has been widely tuned through superconductivity and monitored by Fourier Transform Infrared spectroscopy. The sharp transparency window which appears in the extinction spectrum exhibits a relative modulation up to 50% activated by temperature change. The interplay between ohmic and radiative damping, which can be independently tuned and controlled, allows for engineering the electromagnetically induced transparency of the metamaterial far beyond the current state-of-the-art, which relies on standard metals or low-Tc superconductors.

Abstract-A new, low temperature long-pass cell for mid-infrared to terahertz spectroscopy and synchrotron radiation use

Fridolin Kwabia Tchana¹, Fabrice Willaert¹, Xavier Landsheere¹, Jean-Marie Flaud¹, Leatitia Lago², Mylène Chapuis², Christian Herbeaux², Pascale Roy², and Laurent Manceron²

¹LISA, Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Université Paris-Est Créteil (UPEC) et Université Paris-Diderot (UPD), 61 Avenue du Général de Gaulle, 94010 Créteil Cedex, France
²High Vacuum Group and Beamline AILES, Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Gif-sur-Yvette, France 

http://rsi.aip.org/resource/1/rsinak/v84/i9/p093101_s1?isAuthorized=no

A new cell has been designed for accurate spectroscopic measurements in the 80–400 K temperature range with variable path lengths from 3 to more than 141 m. The spectral coverage at these temperatures ranges from the visible to less than 10 cm⁻¹, thanks to the use of diamond windows. The design of the cryostat and vacuum setups allows vibration-free operation. The equipment provides temperature homogeneity and pressure control to better than 2% over the 100–400 K and the 0.1–1000 mbar ranges. Remote-controlled opto-mechanical systems enable in situ adjustments as well as changes of the optical path length within half an hour, in order to optimize measurement time in an open user facility. It allows then to meet the specific requirements of high resolution measurements on the Far-Infrared AILES beamline at SOLEIL as well at the LISA facility, in Créteil, in the mid-IR. This new instrument opens up the way for many experiments in the field of high-resolution gas-phase IR spectroscopy, in particular, in quantitative spectroscopy for atmospheric applications: measurements of absorption line parameters (absolute intensities, cross sections, and pressure-induced widths) using Fourier transform spectroscopy. The design and performance of the equipment are briefly presented and illustrated on spectroscopic examples.