Bulletin of the American Physical Society
APS March Meeting 2013
Volume 58, Number 1
Monday–Friday, March 18–22, 2013; Baltimore, Maryland
Session C22: Metamaterials and THz Spectroscopy |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Matt Doty, University of Delaware Room: 324 |
Monday, March 18, 2013 2:30PM - 2:42PM |
C22.00001: Hyperbolic dispersion of graded anisotropic metamaterial with optical Kerr effect Ka Shing Hui, Hon Ping Lee, Kin Wah Yu We have investigated the tunable optical dispersion relation from an anisotropic graded material with optical Kerr effect under the influence of external electric field. The permittivity of the material depends on incident electric field $\tilde{\epsilon} =\epsilon+\chi |E |^2 $ . In particular, a graded metallic thin film which dielectric permittivity is anisotropic in the parallel and perpendicular directions is considered. The permittivity in parallel direction is described by the graded Drude model and the permittivity in the perpendicular direction is described by epsilon-near-zero (ENZ) metamaterial. For ENZ metamaterial, the local electric field is enhanced such that $\chi |E |^2\sim\epsilon$. As a result, the permittivity of ENZ metamaterial can be tuned by the optical Kerr effect. The dispersion relation and the electric field distribution are also examined in the quasi-static condition. By varying the intensity of the incident electric field, the dispersion relation can be switched from elliptical to hyperbolic which allow us to control light prorogation. Furthermore, the implication of the switching from the elliptical to hyperbolic dispersion on the Goos-H\"{a}nchen shift will be studied. [Preview Abstract] |
Monday, March 18, 2013 2:42PM - 2:54PM |
C22.00002: ABSTRACT WITHDRAWN |
Monday, March 18, 2013 2:54PM - 3:06PM |
C22.00003: Nonlinear Propagation in Fishnet Metamaterials Haim Suchowski, Kevin O'Brien, Zi Jing Wong, Xiaobo Yin, Xiang Zhang We present experimental and theoretical investigations of four-wave mixing in negative index metamaterials at optical frequencies with the goal of demonstrating a phase matched backward wave. The nonlinear propagation in thick fishnet structures are examined, in order to show an experimental observation of backward nonlinear optical generation in negative refractive index materials. We have fabricated a fishnet metamaterial with a negative refractive index in the near infrared and have measured its index using spectrally and spatially resolved interferometry. An infrared four wave mixing process was chosen to ensure that the linear properties of the fishnet can be treated with effective medium theory. The signal and idler are obtained from two optical parametric oscillators driven by synchronized femtosecond lasers. We find that with a counter-propagating pump and signal one can obtain perfect phase matching for the backward propagating idler and a large enough phase mismatch to suppress the forward propagating idler. Our efforts towards an experimental demonstration of nonlinear phase matching in negative index optical metamaterials will be discussed. [Preview Abstract] |
Monday, March 18, 2013 3:06PM - 3:18PM |
C22.00004: Metagratings for Diffraction Based, Compact, Holographic Imaging Sandeep Inampudi, Viktor A. Podolskiy Recent developments in semiconductor technology brought to life a new generation of highly-compact visible-frequency cameras. Unfortunately, straight forward extension of this progress to low-frequency domains (such as mid-IR imaging) is impossible since the pixel size at these frequencies is limited by free-space diffraction limit. Here we present an approach to realize highly-compact imaging systems at lower frequencies. Our approach takes advantage of high refractive index of materials commonly utilized in semiconductor detectors of mid-IR radiation, accompanied by metagratings, structures with engineered diffraction properties, to achieve a 10-fold reduction in the pixel size. In contrast to conventional refraction-based imaging, the approach essentially produces a digital hologram -- a 2D projection of the 3D optical field, enabling a post-imaging ``refocusing'' of the picture. The perspectives of numerical recovery of the optical field and the stability of such recovery are discussed. [Preview Abstract] |
Monday, March 18, 2013 3:18PM - 3:30PM |
C22.00005: Multiple-band transmission in an acoustic metamaterial Ru-Wen Peng, Dong-Xiang Qi, Ren-Hao Fan, Xian-Rong Huang, Ming-Hui Lu, Xu Ni, Qing Hu, Mu Wang We demonstrate that acoustic waves can achieve extremely flat transmission through a metallic grating under oblique incidence within multiple frequency bands separated by Wood's anomalies. At the low-frequency band, the transmission of acoustic wave is independent of the frequency and presents a flat curve with the transmission efficiency reaching about 100{\%}; while at high-frequency bands, the transmission decreases to be lower flat curves due to the diffraction effect. The transmission efficiency is insensitive to the thickness of the grating. This phenomenon is verified by experiments, numerical simulations, and an analytical model. The broadband high transmission is attributed to the acoustic impedance matching between the air and the grating. This research may open up a field for various potential applications of acoustic gratings, including broadband sonic imaging and screening, grating interferometry, and antireflection cloaking. References: D. X. Qi, R. H. Fan, R. W. Peng et al., Appl. Phys. Lett. 101, 061912 (2012); and R. H. Fan, R. W. Peng, X. R. Huang et al., Adv. Mater. 24, 1980 (2012). [Preview Abstract] |
Monday, March 18, 2013 3:30PM - 3:42PM |
C22.00006: Two-Dimensional Control over Gradient Index in a VO$_2$ Memory Metamaterial Michael Goldflam, Tom Driscoll, Daniel Barnas, Matthew Royal, Talmage Tyler, Nan Jokerst, David Smith, Giwan Seo, Bong-Jun Kim, Hyun-Tak Kim, Dimitri Basov We have demonstrated the creation of spatial gradients in the optical properties of a metamaterial device through tuning of a vanadium dioxide layer that interacts with an array of split ring resonators (SRR). Application of a transient electrical pulse across the metamaterial-VO$_2$ system leaves persistent changes in the properties of the metamaterial due to the hysteresis of the insulator-to-metal transition in VO$_2$. Through modification of contact geometry, pulse shape, and pulse duration, we have shown increased control over such devices allowing for independent tuning of individual sections of our hybrid VO$_2$-SRR device through the application of several transient voltage pulses. The characteristics of the gradients resulting from the voltage pulses were measured using infrared transmission spectroscopy. We observed a 15\% variation in the magnitude of transmission with spatial scales on the order of one wavelength at the resonance frequency. Thus we have demonstrated the viability of similar tunable metamaterial devices for uses in communications and beam steering. [Preview Abstract] |
Monday, March 18, 2013 3:42PM - 3:54PM |
C22.00007: Beating diffraction limit in an absorptive superlens Meng Xiao, Che Ting Chan It is well known that a slab with both permittivity and permeability equals -1+i$\delta$ can achieve super resolution and its mechanism can be understood with the idea of complementary material. In practice, meta-materials are always absorptive and the absorption sets an upper limit for the image resolution. Here, we study the image formation of stratified complementary slabs in the time domain. Instead of only one slab of super lens, we consider a stack of AB structured complementary slabs, where A is a super lens and B is normal material. We show that the superlens stack can beat the diffraction limit even in the presence of loss if the source has a time-dependent intensity profile. We derived a general analytical expression for the group velocity of an arbitrary k component including evanescent waves near frequency where ``complementary'' is satisfied and the analytical results can explain the super solution in the presence of loss. And our results shows that, with a Gaussian shaped pulse illumination, the image resolution can be improved by about 45\% relative to harmonic illumination for the same system. [Preview Abstract] |
Monday, March 18, 2013 3:54PM - 4:06PM |
C22.00008: Lamb Shift in the Near Field of Hyperbolic Metamaterial Half Space Nai Jing Deng, Kin Wah Yu Hyperbolic metamaterials give a large magnification of the density of states in a specific frequency ranges, and has motivated various applications in emission lifetime reduction, strong absorption, and extraordinary black body radiation, etc. The boost of vacuum energy, which is proportional to the density of states, is expected in hyperbolic metamaterial. We have studied the Lamb shift in vacuum-hyperbolic-metamterial half spaces and shown the non-trivial role of vacuum energy. In our calculation, the easy-fabricated multilayer structure is employed to generate a hyperbolic dispersion relation. The spectrum of hydrogen atoms is calculated with a perturbation method after quantizing the half spaces with a complete mode expansion. It appears that the shift of spectrum is mainly contributed by the terahertz response of materials, which has been well described and predicted in both theories and experiments. [Preview Abstract] |
Monday, March 18, 2013 4:06PM - 4:18PM |
C22.00009: Complex Oxide Thin Film Metamaterial Structures for THz applications D. Shreiber, R. Cravey, M.W. Cole Metamaterials operating in the frequency range of 0.1-1.5 THz are of a special interest for multiple Army applications such as communications, NDE of materials, and detection of chem./bio hazards. Recently proposed dielectric metamaterials present an intriguing venue for the developments in this field due to their low propagation losses and ease of fabrication. These dielectric metamaterials were implemented in bulk and in thick films. Tunability of ferroelectric complex oxides is achieved by applied bias voltage and constitutes an additional benefit for multiple applications. However, real-life applications require usage of relatively low bias voltage which is achievable only by using a ferroelectric complex oxide thin-film. Although the physical dimensions of the thin film metamaterial structures suggest their usage in IR-optical spectrum, their very high dielectric constant provides a rare opportunity to lower their resonant frequency to the frequency range of interest. This presentation will discuss the opportunities and challenges associated with the metamaterial complex oxide thin film structures including numerical investigations of the resonant frequency shift as a function of the complex oxide thin film dielectric constant and thickness. [Preview Abstract] |
Monday, March 18, 2013 4:18PM - 4:30PM |
C22.00010: Analysis of Cyclotron Resonance Spectroscopy in a Landau-quantized 2DEG using Characteristic Matrix Methods David Hilton We develop a new characteristic matrix-based method to analyze cyclotron resonance experiments in high mobility ($\mu_e = 3.7 \times 10^6 ~\mathrm{cm}^2~\mathrm{V}^{-1} ~\mathrm{s}^{-1}$) two-dimensional electron gas samples where direct interference between primary and satellite reflections has previously limited the frequency resolution. We use terahertz time-domain spectroscopy to measure the cyclotron resonance and extract the dephasing lifetime where multiple pulses from the substrate with a separation of $\sim 15$ ps directly interfere in the time-domain. We find a cyclotron dephasing lifetime of $15.1\pm 0.5$ ps at 1.5 K and $5.0\pm 0.5$ ps at 75 K. [Preview Abstract] |
Monday, March 18, 2013 4:30PM - 4:42PM |
C22.00011: Tunable Plasmonic Crystals Induced from a Two Dimensional Electron Gas Gregory Dyer, Gregory Aizin, S. James Allen, Albert Grine, Don Bethke, John Reno, Eric Shaner A two dimensional electron gas (2DEG) with periodic variation of its screening,$^{1}$ geometry,$^{2}$ or carrier density$^{3}$ provides an electromagnetic medium for the formation of a broadly tunable plasmonic crystal (PC). By using a periodic gate to control the 2DEG density in GaAs/AlGaAs heterostructures, we have induced terahertz (THz) PCs consisting of several bipartite crystal units cells. The PC band structure, Tamm states, and electromagnetically induced transparency phenomena are observed utilizing a gate-controlled defect adjacent to the PC to generate a plasmonic mixing photovoltage. These integrated PCs have potential applications in the areas of frequency selective THz detection, strong light-matter interaction, and planar metamaterials. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. The work at Sandia National Laboratories was supported by the DOE Office of Basic Energy Sciences. $^{1}$U. Mackens, et. al., Phys. Rev. Lett. \textbf{53}, 1485 (1984). $^{2}$V. M. Muravev, et. al., Phys. Rev. Lett. \textbf{101}, 216801 (2008). $^{3}$G. C. Dyer, et. al., Phys. Rev. Lett. \textbf{109}, 126803 (2012). [Preview Abstract] |
Monday, March 18, 2013 4:42PM - 4:54PM |
C22.00012: Controlling Metamaterial Field Enhancement at Terahertz Frequencies George Keiser, Huseyin Seren, Xin Zhang, Richard Averitt With the advent of metamaterials has come an unprecedented ability to manipulate and engineer the index of refraction, n, and impedance, Z of materials. Engineering these far field properties has led to exciting developments such as negative index materials, electromagnetic cloaks, and perfect lensing. However, metamaterials can also be used to engineer designer microscopic charge distributions, current distributions, and polarizabilities. For instance, the on-resonance charge distribution in the capacitive gap of a split ring resonator (SRR) creates a localized region of high electric field enhancement that has seen prominent application in recent work. Here, we present a method to tune the magnitude of this resonant electric field enhancement. Via structural manipulation of the coupling between the SRR and a non-resonant closed conducting ring, we are able to increase and decrease the oscillator strength of the SRR and thus the field enhancement in the SRR's capacitive gap. We present numerical simulations and experimental measurements at terahertz frequencies to confirm this result. [Preview Abstract] |
Monday, March 18, 2013 4:54PM - 5:06PM |
C22.00013: Characterization of Micromachined Air-lifted Terahertz Antenna Arrays Chang Long, Luyi Yan, Cheolbok Kim, Daniel J. Arenas, Yong-Kyu Yoon, David B. Tanner We have designed and fabricated micromachined three dimensional (3-D) air-lifted monopole antenna arrays. The air-lifted antenna arrays have been fabricated using high-aspect-ratio epoxy structures defined by ultraviolet (UV) lithography and subsequent metallization by thin film metal sputtering. The uniqueness of this monopole antenna lies in its strong coupling to incident THz waves with E-field perpendicular to the substrate, which is not the case with most substrate-printed antennas. A Bruker 113v FTIR system has been used to characterize the fabricated arrays for both $\textit{s}$- (E-field perpendicular to the plane of incidence) and $\textit{p}$- (E-field parallel to the plane of incidence) polarized light over 30-600 $cm^{-1}$/1-20 THz. We measured monopole antenna arrays with diameters of 5 $\mu$m and different heights from 20 $\mu$m to 60 $\mu$m. Measurement results are compared to resonant frequency calculations and simulations. The results are in good agreement with those of the simulations. [Preview Abstract] |
Monday, March 18, 2013 5:06PM - 5:18PM |
C22.00014: Photo-imprinted diffraction gratings for controlling terahertz radiation. Ioannis Chatzakis, Philippe Tassin, Liang Luo, Nian-Hai Shen, Lei Zhang, Jigang Wang, Thomas Koschny, Costas M. Soukoulis We investigate the diffraction of terahertz radiation by photo-imprinted conductive periodic structures. The diffraction gratings are created by optically projecting the image of a metal mask on a high-resistivity GaAs substrate, resulting in a periodic structure of photo-excited charge carriers that scatter terahertz waves. Using terahertz time domain spectroscopy, we show that the terahertz transmission spectra depend characteristically on the lattice constant of the photo-imprinted linear gratings and on the polarization state of the incident terahertz wave, but the transmitted radiation does not depend on the duty cycle of the projected gratings. These experimental results, combined with computer simulations of the structure, confirm that the gratings are purely diffraction-based and are not caused by surface modes or quasistatic resonances. We also demonstrate two-dimensional photo-imprinted diffraction gratings. We anticipate that our findings will have significant impact on the development of reconfigurable components for controlling the terahertz radiation. [Preview Abstract] |
Monday, March 18, 2013 5:18PM - 5:30PM |
C22.00015: Nonlinear THz Plasmonic Disk Resonators Huseyin Seren, Jingdi Zhang, George Keiser, Scott Maddox, Kebin Fan, Lingyue Cao, Seth Bank, Xin Zhang, Richard Averitt Particle surface plasmons (PPSs) at visible wavelengths continue to be actively investigated with the goal of nanoscale control of light. In contrast, terahertz (THz) surface plasmon experiments are at a nascent stage of investigation. Doped semiconductors with proper carrier density and mobility support THz PSPs. One approach is to utilize thick doped films etched into subwavelength disks. Given the ease of tuning the semiconductor carrier density, THz PSPs are tunable and exhibit interesting nonlinear THz plasmonic effects. We created THz PSP structures using MBE grown 2um thick InAs films with a doping concentration of 1e17cm$^{\mathrm{-3}}$ on 500um thick semi-insulating GaAs substrate. We patterned 40um diameter disks with a 60um period by reactive ion etching. Our THz time-domain measurements reveal a resonance at 1.1THz which agrees well with simulation results using a Drude model. A nonlinear response occurs at high THz electric field strengths (\textgreater 50kV/cm). In particular, we observed a redshift and quenching of the resonance due to impact ionization which resulted in changes in the carrier density and effective mass due to inter-valley scattering. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700