Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session K36: Novel Photonic and Optical Phenomena in Nanostructured Materials |
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Sponsoring Units: DCMP DMP Chair: Parveen Kumar, University of California, Merced Room: 299 |
Wednesday, March 15, 2017 8:00AM - 8:12AM |
K36.00001: Overflow of a dipolar exciton trap at high magnetic fields Sebastian Dietl, Katarzyna Kowalik-Seidl, Lukas Hammer, Dieter Schuh, Werner Wegscheider, Alexander Holleitner, Ursula Wurstbauer We study the photoluminescence of trapped dipolar excitons (IX) in coupled double GaAs quantum wells at low temperatures and high magnetic fields. A voltage-tunable electrode geometry controls the strength of the quantum confined Stark effect and defines the lateral trapping potential. Furthermore, it enhances the IX lifetime, enabling them to cool down to lattice temperature. We show that a magnetic field in Faraday configuration effectively prevents the escape of unbound photogenerated charge carriers from the trap area, thus increasing the density of dipolar excitons. For large magnetic fields, we observe an overflow of the IX trap and an effectively suppressed quantum confined Stark effect. [Preview Abstract] |
Wednesday, March 15, 2017 8:12AM - 8:24AM |
K36.00002: Double gyroid photonic crystal: synthesis and mid-infrared photonic characterization Siying Peng, Runyu Zhang, Emil Khabiboulline, Vitoria Barim, Hongjie Chen, Philip Hon, Juan Garcia, Luke Sweatlock, Paul Braun, Harry Atwater Gyroids are triply symmetric and have surfaces containing no straight lines. Single gyroid (SG) photonic crystals have a large band gap, while double gyroids (DG) with P-breaking symmetry possess Weyl points and topologically non-trivial surface states. These topologically protected states give rise to backscattering immune unidirectional transport. We have synthesized and characterized the first mid-IR gyroid photonic crystals, including both SGs and DGs with Weyl points. Polymer gyroid scaffold was written by DLW, followed by ALD of Al$_{\mathrm{2}}$O$_{\mathrm{3}}$, polymer removal and conformally coating of a-Si. The resulting DGs have Weyl points at 8 $\mu$ m and k between 0.3-0.5$\pi $/a. Characterization of SG and DG have been performed by angle resolved mid-IR spectroscopy. The photonic bandstructure is constructed from angle resolved reflectance and transmittance spectra, all the way close to the light line. Constructed bandstructures from SGs exhibit a photonic bandgap. For DGs the bandstructures reveal defect photonic states emerging inside the bandgap. Strategies to observe protected surface states in DGs will be discussed. [Preview Abstract] |
Wednesday, March 15, 2017 8:24AM - 8:36AM |
K36.00003: Microwave transmission measurements through a magnetic photonic crystal Mohamed Zein Radwan, Graeme Dewar We have measured the 12 -- 18 GHz microwave transmission through, and the reflection from, a nickel zinc ferrite penetrated by a wire lattice. The metamaterial efficiently transmitted microwaves under conditions for which the index of refraction was negative. The wires, 0.29 mm in diameter, were threaded through Teflon tubes and centered in holes 1.7 mm in diameter drilled through the ferrite. The holes formed a square array with a lattice constant of 3.0 mm. A ferrite sample containing the wire array filled a length of 3.0 cm inside standard WR-62 waveguide and a static magnetic field between 0.042 and 13.0 kOe was applied parallel to the wires. We measured the transmission relative to an open waveguide and the reflection relative to a reflective metal plate across the waveguide face. We observed transmission modes at combinations of magnetic field and microwave frequency for which both the permeability of the ferrite and permittivity of the wire array were negative. [Preview Abstract] |
Wednesday, March 15, 2017 8:36AM - 8:48AM |
K36.00004: Strong coupling between light and subwavelength microstructure of the carbon aerogels Ai Du, Wei Sun, Yu Feng, Hongqiang Wang, Jun Shen, Bin Zhou Owing to its diverse compositions and unique properties which could fill the gap between condensed and gas-state matter aerogels are now regarded as a new state of matter. Recently, we found that subwavelength microstructure obviously affect the reflectivity. The subwavelength structure of carbon aerogels was controlled by adjusting the sol-gel process and carbonizing the resorcinol-formaldehyde aerogels. A roughly positive correlation between reflectivity and density was found. Moreover, the smaller the skeleton and pore size is, the lower the reflectivity is. We got the minimum reflectance about 0.19 {\%}. Carbon aerogels were activated using CO$_{\mathrm{2}}$ at 1000$^{\mathrm{o}}$C to induce the micropore (\textless 2 nm) without changing the density. The reflectivity of carbon aerogels decreased sharply after activation, indicating that the structure much smaller than wavelength could affect the light propagation. We attribute this behavior to the indirect electromagnetic-electronmicrostructure interaction. The mean free path $\lambda $ of the electrons strongly decreases when the conductor is smaller than $\lambda $, leading to an extra absorption besides considering the Joule's effect In addition we induced nanostructured metal to increase the hot electron loss, to further reduce the reflectivity. [Preview Abstract] |
Wednesday, March 15, 2017 8:48AM - 9:00AM |
K36.00005: Hybrid polariton bands in an organic-dye-doped nanostructure Ruwen Peng, Kun Zhang, Wen-Bo Shi, Yue Xu, Mu Wang Recently, controlling light-matter interactions by nanostructures has attracted much attention due to both fundamental and practical interest. In this work, we try to achieve multiple polariton bands in organic-dye-doped nanostructures by hybrid coupling among excitons, photons and surface plasmon polaritons(SPPs). We have demonstrated experimentally the hybrid coupling among molecular excitons, SPPs, and Fabry-Perot(FP) mode in a nanostructured cavity, where a J-aggregates doped PVA(polyvinyl alcohol) layer is inserted between a silver grating and a thick silver film. By tuning the thickness of the doped PVA layer, the FP cavity mode efficiently couples with the molecular excitons, forming two nearly dispersion-free modes. The dispersive SPPs interact with these two modes while increasing the incident angle, leading to the formation of three hybrid polariton bands. Besides, we have also experimentally presented multimode photon-exciton coupling in an organic-dye-attached photonic quasicrystal. This work may inspire related studies on hybrid light-matter interactions, and achieve potential applications on multimode polariton lasers and optical spectroscopy. References: 1) K. Zhang et al., Appl. Phys. Lett. 108, 193111 (2016); 2) K. Zhang et al., Opt. Lett. (accepted, 2016). [Preview Abstract] |
Wednesday, March 15, 2017 9:00AM - 9:12AM |
K36.00006: Photonic effects in natural nanostructures Rafael Ramón Rey González, Claudia Patricia Barrera Patiño Nature exhibits a great variety of structures and nanostructures. In particular the interaction light-matter has a strong dependence with the shape of the nanostructures. In some cases, in the so called structural color, ordered arrays of nanostructures play a very critical role. One of the most interesting color effects is the iridescence, the angular dependence of the observed color in some species of butterflies, insects, plants, beetles, fishes, birds and even in minerals. In the last years, iridescence has been related with photonic properties. In the present work, we present a theoretical study of the photonic properties for different patterns that exist in natural nanostructures present in wings of butterflies that exhibit iridescence. The nanostructures observed in these cases present spatial variations of the dielectric constant that are possible to model them as 1D and 2D photonic crystal. Partial photonic gaps are found as function of lattice constant, dielectric contrast and geometrical configuration. Also, disordered effects are considered. [Preview Abstract] |
Wednesday, March 15, 2017 9:12AM - 9:24AM |
K36.00007: A highly efficient and broadband photonic circular polarizer in optical range M.H Alizadeh Miniaturization of bulky optical devices to micro and nano scales, has been at the forefront of cutting-edge research in the photonics community. The core idea of this line of research is to move towards ever smaller photonic components that can function even more efficiently than their bulky counterparts. One of such optical elements are Quarter Wave Plates, which convert a linearly polarized light to a circularly polarized light. Upon realization of nanoscale circular polarizers, they would find immediate applications in various areas, from Quantum information processing to nanoscale integrated chips and on-chip photonic communications. In this context, we present a novel nano-sized photonic element, that can function as a circular polarizer in the visible range of spectrum and with very high efficiency. More specifically, we demonstrate that when light impinges on two closely fabricated silicon nanowires, the optical modes of these structures interact and the subsequent lifting of degeneracy of the degenerate fundamental modes of subwavelength nanowires, induces a phase shift in the modes and converts the incident linearly polarized light to a circularly polarized one. [Preview Abstract] |
Wednesday, March 15, 2017 9:24AM - 9:36AM |
K36.00008: Effect of strong coupling between photonics mode and molecular exciton on Franck-Condon blockade Amrit Poudel, Liang-Yan Hsu, Mark Ratner We present an open-quantum system approach based on density matrix to study the effect of strong coupling between photonics modes and excitons on Franck-Condon (FC) blockade in molecular systems. Recent experiments have demonstrated that strong coupling between cavity photon and molecular exciton leads to enhancement of exciton conductance in disordered organic molecular systems. Here we analyze the role of strong coupling between cavity photon and exciton on FC blockade at normal and Coulomb blockade regimes. We identify parameter regimes where strong coupling to photonics mode suppresses or enhances the FC blockade and propose relevant experiments for cavity induced FC blockade. [Preview Abstract] |
Wednesday, March 15, 2017 9:36AM - 9:48AM |
K36.00009: Femtosecond pump-probe second-harmonic generation from silicon nanogratings. Yong An, Avery Green, Alain Diebold Silicon nanogratings with fin-like nanogroove arrays have been used in nanoelectronics to build field effect transistors (FinFETs), which have attracted enormous attention due to their superior electronic properties. They can also be used in photonic systems to achieve desired linear and nonlinear optical functionalities. Here we perform second-harmonic generation (SHG) measurements using femtosecond laser pulses on a set of 28, 42, and 65 nm-pitch Si nanogratings to study rotational anisotropy and ultrafast dynamics of SHG. We observe that in pump-probe SHG experiments, the SHG signal from a Si nanograting can be instantaneously enhanced 32{\%} by an autocorrelated pump pulse. The enhancement is caused by pump-induced transient polarization of photoexcited charge in the nanogratings. We also find that charge photoinjection magnifies the quadrupole SHG component significantly more than the dipole SHG component. These results provide insight into the SHG response at the nanoscale, dynamic behaviors of SHG upon photoexcitation, and ultrafast dynamics of photoexcited carriers in Si nanogratings. Furthermore, SHG results from nanogratings of different pitches provide guidance for using the SHG technique to characterize feature dimensions in Si nanogratings. [Preview Abstract] |
Wednesday, March 15, 2017 9:48AM - 10:00AM |
K36.00010: Quadratic Electro-optic Effect in Nanometallic Particles in Glass; Comparison with Iodine-doped Nonconjugated Conductive Polymer Justin Van Cleave, Mrinal Thakur Quadratic electro-optic effect in gold nanoparticles in glass has been measured using field-induced birefringence at 633 nm. The gold particle sizes have been estimated using the surface plasmon resonance spectra. In a typical example, a phase change of about 5x10$^{\mathrm{-4}}$ has been observed for a 4 cm long gold-glass sample (particle size \textasciitilde 48 nm) at an applied ac field of about 0.2 V/micron. The measured Kerr coefficient is about a factor of 10$^{\mathrm{5}}$ less compared to an iodine-doped nonconjugated conductive polymer. The effect of particle-size, concentration and resonance enhancements have been considered to compare the nonlinearities. The results are consistent with the subnanometer size of the metallic quantum dots created upon doping and charge-transfer involving the isolated double-bond in nonconjugated conductive polymer. [Preview Abstract] |
Wednesday, March 15, 2017 10:00AM - 10:12AM |
K36.00011: Abstract Withdrawn
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Wednesday, March 15, 2017 10:12AM - 10:24AM |
K36.00012: Open quantum systems, non-Hermitian systems: Bound states in continuum vs. spectral singularities Savannah Garmon Bound states residing directly in the scattering continuum were first predicted in 1929 [1] but only verified in optical waveguide array experiments quite recently. In this talk, we analyze a model for one such experiment [2] to demonstrate that the {\it bound state in continuum} can be viewed as a resonance state for which the imaginary part of the complex eigenvalue vanishes as a result of quantum interference at specific parameter values. We then introduce a non-Hermitian extension of this model that incorporates a localized energy input into the array. We show that the energy input can again be used to push the resonance state into the continuum, but in this case it results in a standing wave that extends throughout the array. This resonance embedded in the continuum is also referred to as a {\it spectral singularity} in part because the transmission diverges at the embedded energy [3]; hence, this state is equivalent to a lasing mode. As an application, we show how the lasing condition can be obtained with an arbitrarily small energy input. [1] J. von Neumann and E. Wigner, Phys. Z. {\bf 30}, 465 (1929); [2] Y. Plotnik, et al, Phys. Rev. Lett. {\bf 107}, 183901 (2011); [3] S. Garmon, M. Gianfreda, and N. Hatano, Phys. Rev. A {\bf 92}, 022125 (2015). [Preview Abstract] |
Wednesday, March 15, 2017 10:24AM - 10:36AM |
K36.00013: Lasing in Er doped GaN multiple-quantum well structures Vinh Ho, Nguyen Vinh Erbium doped GaN have attracted much attention due to their capability to provide highly thermal stable optical emission in technologically important wavelengths. There is a continued need to exploring effective mechanisms to further improve the quantum efficiency of the 1.54 $\mu $m emission in this material. We report photoluminescence and direct evidence of two mechanisms responsible for the excitation of Er3$+$ ions in GaN/AlN multiple quantum wells (MQWs:Er) grown by metal organic chemical vapor deposition. The emission intensity from our MQWs:Er increases significantly, compared with those from a single layer. We will discuss the influence of the quantum well and barrier width on the photoluminescence emission at 1.54 $\mu $m. These results demonstrate the lasing in MQWs:Er multiple-quantum well structures at 1.54 $\mu $m. [Preview Abstract] |
Wednesday, March 15, 2017 10:36AM - 10:48AM |
K36.00014: Doppler Effect on Structure Period of Nonlinear Laser Lithography Ozgun Yavuz, Semih Kara, Onur Tokel, Ihor Pavlov, Fatih Omer Ilday Recently, Nonlinear Laser Lithography (NLL) was developed for large-area, nanopatterning of surfaces [1]. In NLL, nanopatterns emerge through coherent scattering of the laser from the surface, and its interference with the incident beam. The period of the structures is determined by the laser wavelength. It has been shown by Sipe that the period depends on the laser incidence angle ($\theta$) as $\lambda/(1\pm sin\theta)$ [2]. Here, we show that the period not only depends on this angle, but also on the polarisation angle. We update the Sipe equation as $\lambda/(1\pm sin\theta sin\alpha)$, where '$\alpha$' is the angle between scanning direction and polarisation. The physical reason behind this is found through a formal analogy to Doppler effect. In Doppler effect, the measured wavelength of a moving emitter is given as $\lambda/(1\pm c/vsin\theta)$, where '$\theta$'is the angle between observer and the direction of emitter, 'c' is the speed of observer, 'v' is speed of source. In NLL, velocity of source can be written as $vsin\theta$, and the period equation can be shown to take its new form. We believe that this is the first application of Doppler effect in laser-processing of solid materials.[1]Nature Photonics,7,897(2013). [2]Physical Review B,27,1141(1982). [Preview Abstract] |
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