Abstract-Photo-generated metamaterials induce modulation of CW terahertz quantum cascade lasers.

Francesco P Mezzapesa, Lorenzo L Columbo, Carlo Rizza, Massimo Brambilla, Alessardro Ciattoni,Maurizio Dabbicco, Miriam S Vitiello, Gaetano Scamarcio

http://www.pubfacts.com/detail/26549166/Photo-generated-metamaterials-induce-modulation-of-CW-terahertz-quantum-cascade-lasers

Periodic patterns of photo-excited carriers on a semiconductor surface profoundly modifies its effective permittivity, creating a stationary all-optical quasi-metallic metamaterial. Intriguingly, one can tailor its artificial birefringence to modulate with unprecedented degrees of freedom both the amplitude and phase of a quantum cascade laser (QCL) subject to optical feedback from such an anisotropic reflector. Here, we conceive and devise a reconfigurable photo-designed Terahertz (THz) modulator and exploit it in a proof-of-concept experiment to control the emission properties of THz QCLs. Photo-exciting sub-wavelength metastructures on silicon, we induce polarization-dependent changes in the intra-cavity THz field, that can be probed by monitoring the voltage across the QCL terminals. This inherently flexible approach promises groundbreaking impact on THz photonics applications, including THz phase modulators, fast switches, and active hyperbolic media.

Abstract-Terahertz active spatial filtering through optically tunable hyperbolic metamaterials

http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-37-16-3345

We theoretically consider infrared-driven hyperbolic metamaterials able to spatially filter terahertz (THz) radiation. The metamaterial is a slab made of alternating semiconductor and dielectric layers whose homogenized uniaxial response, at THz frequencies, shows principal permittivities of different signs. The gap provided by metamaterial hyperbolic dispersion allows the slab to stop spatial frequencies within a bandwidth tunable by changing the infrared radiation intensity. We numerically prove the device functionality by resorting to full wave simulation coupled to the dynamics of charge carries photoexcited by infrared radiation in semiconductor layers.

© 2012 Optical Society of America

Abstract-Terahertz active spatial filtering through optically tunable hyperbolic metamaterials

http://arxiv.org/abs/1205.6708

Authors:Carlo Rizza, Alessandro Ciattoni, Elisa Spinozzi, Lorenzo Columbo

Submitted on 30 May 2012)

We theoretically consider infrared-driven hyperbolic metamaterials able to spatially filtering terahertz radiation. The metamaterial is a slab made of alternating semiconductor and dielectric layers whose homogenized uniaxial response, at terahertz frequencies, shows principal permittivities of different signs. The gap provided by metamaterial hyperbolic dispersion allows the slab to stop spatial frequencies within a bandwidth tunable by changing the infrared radiation intensity. We numerically prove the device functionality by resorting to full wave simulation coupled to the dynamics of charge carries photoexcited by infrared radiation in semiconductor layers.

Comments:	3 pages, 4 figures. Submitted for publication on Applied Physics Letters
Subjects:	Optics (physics.optics)
Cite as:	arXiv:1205.6708v1 [physics.optics]

Submission history

From: Alessandro Ciattoni [view email]
[v1] Wed, 30 May 2012 14:48:16 GMT (244kb)