Abstract-Terahertz rare-earth orthoferrite metamaterials by 3-D direct writing technology

X. X. Zeng, R. Wang, X. Q. Xi, B. Li, and J. Zhou

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-13-17056

Terahertz (THz) radiation excites electronic and optical modes of many materials, and controlling interaction of these materials with THz pulses provides a fascinating avenue to achieve unprecedented functionalities in return. Here, woodpile-structured rare-earth orthoferrite metamaterials built with 3-D direct ink writing technology are proposed and experimentally demonstrated. Polarization-independent THz refraction and switching of resonances by varying the number of layers in the structure, as well as the structural parameters and specimen support angle are achieved. Such all-rare-earth-orthoferrite dielectric metamaterials are easy to fabricate and can be very promising in developing efficient and low cost THz functional metadevices.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing 

Abstract-Terahertz Spectrometer of Wavelength Dimensions Based on Extraordinary Transmission

Meredith Henstridge, J. Zhou, L. Jay Guo, R. Merlin

(Submitted on 21 Nov 2016)

https://arxiv.org/abs/1611.07101

Subwavelength-slotted parallel plate waveguides exhibit a localized electromagnetic resonance bound to the slits at a frequency slightly below the transverse electric cutoff [R. Merlin, Phys. Rev. X 2, 031015 (2012)]. The resonance is long-lived and, as opposed to the vanishingly small transmission shown by a single sub-wavelength aperture, it gives perfect transmission for perfectly-conducting plates. We show that the aperture-supported resonances of a pair of slotted copper plates have long lifetimes at THz frequencies. Finite element method calculations show that these bound resonances can have quality factors greater than 100. Effects of plate length and imperfect parallel alignment are also discussed. Using THz time domain spectroscopy, we measured the transmission of a broadband pulse through a test structure for several plate separations. These results suggest that the slotted waveguide can function as a highly compact THz spectrometer.

Abstract-First Demonstration of Amplification at 1 THz Using 25-nm InP High Electron Mobility Transistor Process

X. Mei,  W. Yoshida, M. Lange, J. Lee, J. Zhou, P. Liu, K. Leong, A. Zamora, J.  Padilla, S. Sarkozy, R. Lai, W.R Deal,

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7047678

We report the first ever terahertz monolithic integrated circuit amplifier based on 25-nm InP high electron mobility transistor (HEMT) process demonstrating amplification at 1 THz (1000 GHz) with 9-dB measured gain at 1 THz. This milestone was achieved with a 25-nm InP HEMT transistor, which exhibits 3.5-dB maximum available gain at 1 and 1.5 THz projected $f_{mathrm {mathbf {MAX}}}$ .

Abstract-Compact Superconducting Terahertz Source Operating in Liquid Nitrogen

L. Y. Hao, M. Ji, J. Yuan, D. Y. An, M. Y. Li, X. J. Zhou, Y. Huang, H. C. Sun, Q. Zhu, F. Rudau, R. Wieland, N. Kinev, J. Li, W. W. Xu, B. B. Jin, J. Chen, T. Hatano, V. P. Koshelets, D. Koelle, R. Kleiner, H. B. Wang, and P. H. Wu

https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.3.024006

We report on a liquid-nitrogen-cooled compact source for continuous terahertz (THz) emission. The emitter is a Bi2Sr2CaCu2O8+δ intrinsic Josephson-junction stack embedded between two gold layers and sandwiched between two MgO substrates. The radiation is emitted to free space through a hollow metallic tube acting as a waveguide. The maximum emission power is 1.17  μW. The tunable emission frequency bandwidth is up to 100 GHz with a maximum emission power at 0.311 THz. Since the operation voltage is about 1 V and the current is less than 30 mA, we are able to drive this terahertz source at 77 K with only one commercial 1.5-V battery, just like a torch. This convenient and economical setup may find applications in fields like tracer-gas detection or nondestructive evaluation.

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Abstract-Reversible modulation and ultrafast dynamics of terahertz resonances in strongly photoexcited metamaterials

http://prb.aps.org/abstract/PRB/v86/i12/e125110

I. Chatzakis¹, L. Luo¹, J. Wang^1,*, N.-H. Shen^1,†, T. Koschny¹, J. Zhou^2,‡, and C. M. Soukoulis^1,3
1Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
²Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
³Institute of Electronic Structure and Laser, FORTH, 71110 Heraklion, Crete, Greece

Received 24 December 2011; revised 30 July 2012; published 7 September 2012

We demonstrate an ultrafast reversible modulation of resonant terahertz (THz) response in strongly photoexcited metamaterials. The transient spectral-temporal response of the dipole transition ∼1.6 THz exhibits a distinct nonmonotonic variation as a function of pump fluence. The transition energy shift, strength, spectral width, and density-dependent ultrafast relaxation manifest a remarkable reemergence of the transmission dip after initial quenching. Our simulations, incorporating the first-order diffraction from the photoinduced transient grating, reproduce the salient features, providing a new avenue for designing nonlinear and frequency-agile THz modulators.

©2012 American Physical Society

URL:

http://link.aps.org/doi/10.1103/PhysRevB.86.125110

DOI:

10.1103/PhysRevB.86.125110

PACS:

78.67.Pt, 42.25.Bs, 78.20.-e, 78.47.-p