Designer disordered materials with large, complete photonic band gaps
Florescu, Marian; Torquato, Salvatore; Steinhardt, Paul J.
2009-01-01
We present designs of 2D, isotropic, disordered, photonic materials of arbitrary size with complete band gaps blocking all directions and polarizations. The designs with the largest band gaps are obtained by a constrained optimization method that starts from a hyperuniform disordered point pattern, an array of points whose number variance within a spherical sampling window grows more slowly than the volume. We argue that hyperuniformity, combined with uniform local topology and short-range geometric order, can explain how complete photonic band gaps are possible without long-range translational order. We note the ramifications for electronic and phononic band gaps in disordered materials. PMID:19918087
Two-pattern compound photonic crystals with a large complete photonic band gap
Jia Lin; Thomas, Edwin L.
2011-09-15
We present a set of two-dimensional aperiodic structures with a large complete photonic band gap (PBG), which are named two-pattern photonic crystals. By superposing two substructures without regard to registration, we designed six new aperiodic PBG structures having a complete PBG larger than 15% for {epsilon}{sub 2}/{epsilon}{sub 1} = 11.4. The rod-honeycomb two-pattern photonic crystal provides the largest complete PBG to date. An aperiodic structure becomes the champion structure with the largest PBG. Surprisingly, the TM and TE gaps of a two-pattern photonic crystal are much less interdependent than the PBGs of conventional photonic crystals proposed before, affording interesting capabilities for us to tune the TM and TE PBGs separately. By altering the respective substructures, optical devices for different polarizations (TE, TM, or both) can readily be designed.
NASA Astrophysics Data System (ADS)
Fathollahi Khalkhali, T.; Bananej, A.
2016-06-01
In this study, we analyze the tunability of complete photonic band gap of square and triangular photonic crystal slabs composed of square and hexagonal air holes in anisotropic tellurium background with SiO2 as cladding material. The non-circular holes are infiltrated with liquid crystal. Using the supercell method based on plane wave expansion, we study the variation of complete band gap by changing the optical axis orientation of liquid crystal. Our numerical results show that noticeable tunability of complete photonic band gap can be obtained in both square and triangular structures with non-circular holes.
2D photonic crystal complete band gap search using a cyclic cellular automaton refination
NASA Astrophysics Data System (ADS)
González-García, R.; Castañón, G.; Hernández-Figueroa, H. E.
2014-11-01
We present a refination method based on a cyclic cellular automaton (CCA) that simulates a crystallization-like process, aided with a heuristic evolutionary method called differential evolution (DE) used to perform an ordered search of full photonic band gaps (FPBGs) in a 2D photonic crystal (PC). The solution is proposed as a combinatorial optimization of the elements in a binary array. These elements represent the existence or absence of a dielectric material surrounded by air, thus representing a general geometry whose search space is defined by the number of elements in such array. A block-iterative frequency-domain method was used to compute the FPBGs on a PC, when present. DE has proved to be useful in combinatorial problems and we also present an implementation feature that takes advantage of the periodic nature of PCs to enhance the convergence of this algorithm. Finally, we used this methodology to find a PC structure with a 19% bandgap-to-midgap ratio without requiring previous information of suboptimal configurations and we made a statistical study of how it is affected by disorder in the borders of the structure compared with a previous work that uses a genetic algorithm.
Soukoulis, C.M. |
1993-12-31
An overview of the theoretical and experimental efforts in obtaining a photonic band gap, a frequency band in three-dimensional dielectric structures in which electromagnetic waves are forbidden, is presented.
Zhang, Hai-Feng; Ding, Guo-Wen; Li, Hai-Ming; Liu, Shao-Bin
2015-02-15
In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those parameters, and the larger CPBGs also can be obtained by optimization. The self-collimation in such 2D PPCs also is discussed in theory under TM wave. The theoretical simulations reveal that the self-collimation phenomena can be found in the TM bands, and both the frequency range of self-collimation and the equifrequency surface contours can be tuned by the parameters as mentioned above. It means that the frequency range and direction of electromagnetic wave can be manipulated by designing, as it propagates in the proposed PPCs without diffraction. Those results can hold promise for designing the tunable applications based on the proposed PPCs.
Marichy, Catherine; Muller, Nicolas; Froufe-Pérez, Luis S; Scheffold, Frank
2016-01-01
Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold refractive index contrast that depends on the crystal structure. In the case of the so-called woodpile photonic crystals this threshold is comparably low, approximately 1.9 for the direct structure. Therefore direct or inverted woodpiles made of high refractive index materials like silicon, germanium or titanium dioxide are sought after. Here we show that, by combining multiphoton lithography and atomic layer deposition, we can achieve a direct inversion of polymer templates into TiO2 based photonic crystals. The obtained structures show remarkable optical properties in the near-infrared region with almost perfect specular reflectance, a transmission dip close to the detection limit and a Bragg length comparable to the lattice constant. PMID:26911540
Marichy, Catherine; Muller, Nicolas; Froufe-Pérez, Luis S.; Scheffold, Frank
2016-01-01
Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold refractive index contrast that depends on the crystal structure. In the case of the so-called woodpile photonic crystals this threshold is comparably low, approximately 1.9 for the direct structure. Therefore direct or inverted woodpiles made of high refractive index materials like silicon, germanium or titanium dioxide are sought after. Here we show that, by combining multiphoton lithography and atomic layer deposition, we can achieve a direct inversion of polymer templates into TiO2 based photonic crystals. The obtained structures show remarkable optical properties in the near-infrared region with almost perfect specular reflectance, a transmission dip close to the detection limit and a Bragg length comparable to the lattice constant. PMID:26911540
NASA Astrophysics Data System (ADS)
Marichy, Catherine; Muller, Nicolas; Froufe-Pérez, Luis S.; Scheffold, Frank
2016-02-01
Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold refractive index contrast that depends on the crystal structure. In the case of the so-called woodpile photonic crystals this threshold is comparably low, approximately 1.9 for the direct structure. Therefore direct or inverted woodpiles made of high refractive index materials like silicon, germanium or titanium dioxide are sought after. Here we show that, by combining multiphoton lithography and atomic layer deposition, we can achieve a direct inversion of polymer templates into TiO2 based photonic crystals. The obtained structures show remarkable optical properties in the near-infrared region with almost perfect specular reflectance, a transmission dip close to the detection limit and a Bragg length comparable to the lattice constant.
Photonic band gap structure simulator
Chen, Chiping; Shapiro, Michael A.; Smirnova, Evgenya I.; Temkin, Richard J.; Sirigiri, Jagadishwar R.
2006-10-03
A system and method for designing photonic band gap structures. The system and method provide a user with the capability to produce a model of a two-dimensional array of conductors corresponding to a unit cell. The model involves a linear equation. Boundary conditions representative of conditions at the boundary of the unit cell are applied to a solution of the Helmholtz equation defined for the unit cell. The linear equation can be approximated by a Hermitian matrix. An eigenvalue of the Helmholtz equation is calculated. One computation approach involves calculating finite differences. The model can include a symmetry element, such as a center of inversion, a rotation axis, and a mirror plane. A graphical user interface is provided for the user's convenience. A display is provided to display to a user the calculated eigenvalue, corresponding to a photonic energy level in the Brilloin zone of the unit cell.
Optically tuneable blue phase photonic band gaps
Liu, H.-Y.; Wang, C.-T.; Hsu, C.-Y.; Lin, T.-H.; Liu, J.-H.
2010-03-22
This study investigates an optically switchable band gap of photonic crystal that is based on an azobenzene-doped liquid crystal blue phase. The trans-cis photoisomerization of azobenzene deforms the cubic unit cell of the blue phase and shifts the photonic band gap. The fast back-isomerization of azobenzene was induced by irradiation with different wavelengths light. The crystal structure is verified using Kossel diffraction diagram. An optically addressable blue phase display, based on Bragg reflection from the photonic band gap, is also demonstrated. The tunable ranges are around red, green, and blue wavelengths and exhibit a bright saturated color.
Complete bandgap switching in photonic opals
NASA Astrophysics Data System (ADS)
Aryal, D. P.; Tsakmakidis, K. L.; Hess, O.
2009-07-01
A comprehensive theoretical study of the optical properties and switching competence of double-shell photonic crystals (DSPC) and double-inverse-opal photonic crystals (DIOPC) is presented. Our analysis reveals that a DIOPC structure with a silicon (Si) background exhibits a complete photonic bandgap (PBG), which can be completely switched on and off by moving the core spheres inside the air pores of the inverse opal. We show that the size of this switchable PBG assumes a value of 3.78% upon judicious structural optimization, while its existence is almost independent of the radii of the interconnecting cylinders, whose sizes are difficult to control during the fabrication process. The Si-based DIOPC may thus offer a novel and practical route to complete PBG switching and optical functionality.
Robust photonic band gap from tunable scatterers
Zhang; Lei; Wang; Zheng; Tam; Chan; Sheng
2000-03-27
We show theoretically and experimentally that photonic band gaps can be realized using metal or metal-coated spheres as building blocks. Robust photonic gaps exist in any periodic structure built from such spheres when the filling ratio of the spheres exceeds a threshold. The frequency and the size of the gaps depend on the local order rather than on the symmetry or the global long range order. Good agreement between theory and experiment is obtained in the microwave regime. Calculations show that the approach can be scaled up to optical frequencies even in the presence of absorption. PMID:11018959
Effect of size of silica microspheres on photonic band gap
Dhiman, N. Sharma, A. Gathania, A. K.; Singh, B. P.
2014-04-24
In present work photonic crystals of different size of silica microspheres have been fabricated. The optical properties of these developed photonic crystals have been studied using UV-visible spectroscopy. UV-visible spectroscopy shows that they have photonic band gap that can be tuned in visible and infrared regime by changing the size of silica microspheres. The photonic band gap structures of these photonic crystals have been calculated using MIT photonic band gap package. It also reveals that with the increase in size of silica microspheres the photonic band gap shifts to lower energy region.
Fabrication of photonic band gap materials
Constant, Kristen; Subramania, Ganapathi S.; Biswas, Rana; Ho, Kai-Ming
2002-01-15
A method for forming a periodic dielectric structure exhibiting photonic band gap effects includes forming a slurry of a nano-crystalline ceramic dielectric or semiconductor material and monodisperse polymer microspheres, depositing a film of the slurry on a substrate, drying the film, and calcining the film to remove the polymer microspheres therefrom. The film may be cold-pressed after drying and prior to calcining. The ceramic dielectric or semiconductor material may be titania, and the polymer microspheres may be polystyrene microspheres.
Fabrication of Photonic band gap Materials
Constant, Kristen; Subramania, Ganapathi S.; Biswas, Rana; Ho, Kai-Ming
2000-01-05
A method for forming a periodic dielectric structure exhibiting photonic band gap effects includes forming a slurry of a nano-crystalline ceramic dielectric or semiconductor material and monodisperse polymer microsphere, depositing a film of the slurry on a substrate, drying the film, and calcining the film to remove the polymer microsphere there from. The film may be cold-pressed after drying and prior to calcining. The ceramic dielectric or semiconductor material may be titania, and the polymer microsphere may be polystyrenemicrosphere.
Highly dispersive photonic band-gap prism.
Lin, S Y; Hietala, V M; Wang, L; Jones, E D
1996-11-01
We propose the concept of a photonic band-gap (PBG) prism based on two-dimensional PBG structures and realize it in the millimeter-wave spectral regime. We recognize the highly nonlinear dispersion of PBG materials near Brillouin zone edges and utilize the dispersion to achieve strong prism action. Such a PBG prism is very compact if operated in the optical regime, ~20 mm in size for lambda ~ 700 nm, and can serve as a dispersive element for building ultracompact miniature spectrometers. PMID:19881796
Phase Modulation of Photonic Band Gap Signal
Wang, Zhiguo; Gao, Mengqin; Mahesar, Abdul Rasheed; Zhang, Yanpeng
2016-01-01
We first investigate the probe transmission signal (PTS) and the four wave mixing band gap signal (FWM BGS) modulated simultaneously by the relative phase and the nonlinear phase shift in the photonic band gap (PBG) structure. The switch between the absorption enhancement of PTS and the transmission enhancement of PTS with the help of changing the relative phase and the nonlinear phase shift is obtained in inverted Y-type four level atomic system experimentally and theoretically. The corresponding switch in PTS can be used to realize all optical switches. On other hand, the relative phase and the nonlinear phase shift also play the vital role to modulate the intensity of FWM BGS reflected from the PBG structure. And it can be potentially used to realize the optical amplifier. PMID:27323849
Phase Modulation of Photonic Band Gap Signal.
Wang, Zhiguo; Gao, Mengqin; Mahesar, Abdul Rasheed; Zhang, Yanpeng
2016-01-01
We first investigate the probe transmission signal (PTS) and the four wave mixing band gap signal (FWM BGS) modulated simultaneously by the relative phase and the nonlinear phase shift in the photonic band gap (PBG) structure. The switch between the absorption enhancement of PTS and the transmission enhancement of PTS with the help of changing the relative phase and the nonlinear phase shift is obtained in inverted Y-type four level atomic system experimentally and theoretically. The corresponding switch in PTS can be used to realize all optical switches. On other hand, the relative phase and the nonlinear phase shift also play the vital role to modulate the intensity of FWM BGS reflected from the PBG structure. And it can be potentially used to realize the optical amplifier. PMID:27323849
Simultaneous existence of phononic and photonic band gaps in periodic crystal slabs.
Pennec, Y; Djafari Rouhani, B; El Boudouti, E H; Li, C; El Hassouani, Y; Vasseur, J O; Papanikolaou, N; Benchabane, S; Laude, V; Martinez, A
2010-06-21
We discuss the simultaneous existence of phononic and photonic band gaps in a periodic array of holes drilled in a Si membrane. We investigate in detail both the centered square lattice and the boron nitride (BN) lattice with two atoms per unit cell which include the simple square, triangular and honeycomb lattices as particular cases. We show that complete phononic and photonic band gaps can be obtained from the honeycomb lattice as well as BN lattices close to honeycomb. Otherwise, all investigated structures present the possibility of a complete phononic gap together with a photonic band gap of a given symmetry, odd or even, depending on the geometrical parameters. PMID:20588565
Hypersonic modulation of light in three-dimensional photonic and phononic band-gap materials.
Akimov, A V; Tanaka, Y; Pevtsov, A B; Kaplan, S F; Golubev, V G; Tamura, S; Yakovlev, D R; Bayer, M
2008-07-18
The elastic coupling between the a-SiO2 spheres composing opal films brings forth three-dimensional periodic structures which besides a photonic stop band are predicted to also exhibit complete phononic band gaps. The influence of elastic crystal vibrations on the photonic band structure has been studied by injection of coherent hypersonic wave packets generated in a metal transducer by subpicosecond laser pulses. These studies show that light with energies close to the photonic band gap can be efficiently modulated by hypersonic waves. PMID:18764257
Completely Flat Band in a Crystal of Finite Thickness
NASA Astrophysics Data System (ADS)
Hirashima, Dai S.
2016-04-01
Conditions for the existence of a completely flat band in a crystal of finite thickness are clarified. Furthermore, the condition for the localization of the flat band states near the surfaces is also discussed. It is also found that a completely flat band can appear in a crystal where a lattice point has multiple orbital states. In addition to the known results for honeycomb and diamond lattices, a localized completely flat band is found in a crystal of the wurtzite structure of finite thickness. A completely flat band is also found in many other crystals, but it is extended in the direction perpendicular to the surface.
Measurement of photonic band diagram in non-crystalline photonic band gap (PBG) materials
NASA Astrophysics Data System (ADS)
Man, Weining; Williamson, Eric; Hashemizad, Seyed; Yadak, Polin; Florescu, Marian
2011-03-01
Non-crystalline PBG materials have received increasing attention recently and sizeable PBGs have been reported in quasi-crystalline structures or even in disordered structures. Band calculations for periodic structures produce accurate dispersion relations in them and refraction properties at their surfaces. However, band calculations for non-periodic structures employ large super-cells of N >100 building blocks, and provide little useful information other than the PBG frequency and width. Since band is folded into N bands, within the first Brillouin zone of the supper-cell. Using stereolithography, we construct various quasi-crystalline or disordered PBG materials and perform transmission measurements. The dispersion relations of EM wave (band diagrams) are reconstructed from the measured phase data. Our experiments not only verify the existence of sizeable PBGs in these structures, but also provide detailed information of the effective band diagrams, dispersion relation, group velocity vector, and their angular dependence. Slow light phenomena are also observed in these structures near gap frequencies. This study presents a powerful tool to investigate photonic properties of non-crystalline structures and provides important dispersion information, which is otherwise impossible to obtain.
Highly dispersive photonic band-gap-edge optofluidic biosensors
NASA Astrophysics Data System (ADS)
Xiao, S.; Mortensen, N. A.
2006-11-01
Highly dispersive photonic band-gap-edge optofluidic biosensors are studied theoretically. We demonstrate that these structures are strongly sensitive to the refractive index of the liquid, which is used to tune dispersion of the photonic crystal. The upper frequency band-gap edge shifts about 1.8 nm for δ n=0.002, which is quite sensitive. Results from transmission spectra agree well with those obtained from the band structure theory.
Phononic and photonic band gap structures: modelling and applications
NASA Astrophysics Data System (ADS)
Armenise, Mario N.; Campanella, Carlo E.; Ciminelli, Caterina; Dell'Olio, Francesco; Passaro, Vittorio M. N.
2010-01-01
Photonic crystals (PhCs) are artificial materials with a permittivity which is a periodic function of the position, with a period comparable to the wavelength of light. The most interesting characteristic of such materials is the presence of photonic band gaps (PBGs). PhCs have very interesting properties of light confinement and localization together with the strong reduction of the device size, orders of magnitude less than the conventional photonic devices, allowing a potential very high scale of integration. These structures possess unique characteristics enabling to operate as optical waveguides, high Q resonators, selective filters, lens or superprism. The ability to mould and guide light leads naturally to novel applications in several fields. Band gap formation in periodic structures also pertains to elastic wave propagation. Composite materials with elastic coefficients which are periodic functions of the position are named phononic crystals. They have properties similar to those of photonic crystals and corresponding applications too. By properly choosing the parameters one may obtain phononic crystals (PhnCs) with specific frequency gaps. An elastic wave, whose frequency lies within an absolute gap of a phononic crystal, will be completely reflected by it. This property allows realizing non-absorbing mirrors of elastic waves and vibration-free cavities which might be useful in high-precision mechanical systems operating in a given frequency range. Moreover, one can use elastic waves to study phenomena such as those associated with disorder, in more or less the same manner as with electromagnetic waves. The authors present in this paper an introductory survey of the basic concepts of these new technologies with particular emphasis on their main applications, together with a description of some modelling approaches.
Quantum electrodynamics near a photonic band-gap
NASA Astrophysics Data System (ADS)
Liu, Yanbing; Houck, Andrew
Quantum electrodynamics predicts the localization of light around an atom in photonic band-gap (PBG) medium or photonic crystal. Here we report the first experimental realization of the strong coupling between a single artificial atom and an one dimensional PBG medium using superconducting circuits. In the photonic transport measurement, we observe an anomalous Lamb shift and a large band-edge avoided crossing when the artificial atom frequency is tuned across the band-edge. The persistent peak within the band-gap indicates the single photon bound state. Furthermore, we study the resonance fluorescence of this bound state, again demonstrating the breakdown of the Born-Markov approximation near the band-edge. This novel architecture can be directly generalized to study many-body quantum electrodynamics and to construct more complicated spin chain models.
Quantum information processing with narrow band two-photon state
NASA Astrophysics Data System (ADS)
Lu, Yajun
Application of quantum sources in communication and information processing are believed to bring a new revolution to the on-going information age. The generation of applicable quantum sources such as single photon state and two-photon state, appears to be one of the most difficult in experimental quantum optics. Spontaneous Parametric Down-Conversion (PDC) is known to generate two-photon state, but bandwidth problem makes it less applicable in quantum information processing. The aim of this work is to generate a narrow band two-photon state and apply it to quantum information processing. We start by developing a cavity enhanced PDC device to narrow the bandwidth of the two-photon state. Direct measurement of the bandwidth of the generated state has been made and the quantum theory of such a device has been investigated. An application of this narrow band two-photon state is to generate anti-bunched photons for quantum cryptography, based on the quantum interference between the two-photon state and a coherent state. The feasibility of this scheme for pulsed pump is also investigated. When applying the concept of mode locking in lasers to a two-photon state, we have mode-locked two-photon state which exhibits a comb-like correlation function and may be used for engineering of quantum states in time domain. Other applications such as demonstration of single photon nonlocality, nonlinear sign gate in quantum computation, and direct measurement of quantum beating, will also be addressed.
A complete design flow for silicon photonics
NASA Astrophysics Data System (ADS)
Pond, James; Cone, Chris; Chrostowski, Lukas; Klein, Jackson; Flueckiger, Jonas; Liu, Amy; McGuire, Dylan; Wang, Xu
2014-05-01
Broad adoption of silicon photonics technology for photonic integrated circuits requires standardized design flows that are similar to what is available for analog and mixed signal electrical circuit design. We have developed a design flow that combines mature electronic design automation (EDA) software with optical simulation software. An essential component of any design flow, whether electrical or photonic, is the ability to accurately simulate largescale circuits. This is particularly important when the behavior of the circuit is not trivially related to the individual component performance. While this is clearly the case for electronic circuits consisting of hundreds to billions of transistors, it is already becoming important in photonic circuits such as WDM transmitters, where signal cross talk needs to be considered, as well as optical cross-connect switches. In addition, optical routing to connect different components requires the introduction of additional waveguide sections, waveguide bends, and waveguide crossings, which affect the overall circuit performance. Manufacturing variability can also have dramatic circuit-level consequences that need to be simulated. Circuit simulations must rely on compact models that can accurately represent the behavior of each component, and the compact model parameters must be extracted from physical level simulation and experimental results. We show how large scale circuits can be simulated in both the time and frequency domains, including the effects of bidirectional and, where appropriate, multimode and multichannel photonic waveguides. We also show how active, passive and nonlinear individual components such as grating couplers, waveguides, splitters, filters, electro-optical modulators and detectors can be simulated using a combination of electrical and optical algorithms, and good agreement with experimental results can be obtained. We then show how parameters, with inclusion of fabrication process variations, can
Staude, I; Thiel, M; Essig, S; Wolff, C; Busch, K; von Freymann, G; Wegener, M
2010-04-01
By using direct laser writing into a novel commercially available photoresist and a silicon-double-inversion procedure followed by tempering of the silicon structures, we realize high-quality centered-tetragonal woodpile photonic crystals with complete photonic bandgaps near 1.55 microm wavelength. The 6.9% gap-to-midgap ratio bandgap is evidenced by the comparison of measured transmittance and reflectance spectra with band-structure and scattering-matrix calculations. PMID:20364228
Replication technology for photonic band gap applications
NASA Astrophysics Data System (ADS)
Grigaliunas, V.; Kopustinskas, V.; Meskinis, S.; Margelevicius, M.; Mikulskas, I.; Tomasiunas, R.
2001-06-01
Replication technology was applied for photonic structure fabrication in silicon substrate. It was revealed, that thin thermoplastic polymer layers on silicon substrates may be patterned by hot embossing technique for dry etching masking. Ni mold used for plain hot embossing into polymer layers was fabricated by Ni electrochemical deposition on the reference silicon surface structure, which was obtained by direct electron beam (EB) writing and SF 6/N 2 reactive ion etching (RIE) technique. It is shown that the shape of replicated photonic structures is determined by RIE parameters.
Complete band gaps and deaf bands of triangular and honeycomb water-steel phononic crystals
NASA Astrophysics Data System (ADS)
Hsiao, Fu-Li; Khelif, Abdelkrim; Moubchir, Hanane; Choujaa, Abdelkrim; Chen, Chii-Chang; Laude, Vincent
2007-02-01
Phononic crystals with triangular and honeycomb lattices are investigated experimentally and theoretically. They are composed of arrays of steel cylinders immersed in water. The measured transmission spectra reveal the existence of complete band gaps but also of deaf bands. Band gaps and deaf bands are identified by comparing band structure computations, obtained by a periodic-boundary finite element method, with transmission simulations, obtained using the finite difference time domain method. The appearance of flat bands and the polarization of the associated eigenmodes is also discussed. Triangular and honeycomb phononic crystals with equal cylinder diameter and smallest spacing are compared. As previously obtained with air-solid phononic crystals, it is found that the first complete band gap opens for the honeycomb lattice but not for the triangular lattice, thanks to symmetry reduction.
Effect of disorder on photonic band gaps
NASA Astrophysics Data System (ADS)
Sigalas, M. M.; Soukoulis, C. M.; Chan, C. T.; Biswas, R.; Ho, K. M.
1999-05-01
We study the transmission of electromagnetic waves propagating in three-dimensional disordered photonic crystals that are periodic on the average with a diamond symmetry. The transmission has been calculated using the transfer matrix method. We study two different geometries for the scatterers: spheres and rods connecting nearest neighbors. We find that the gaps of the periodic structure survive to a higher amount of disorder in the rods' case than in the spheres' case. We argue that this is due to the connectivity of the rod structure that exists for any amount of disorder.
Photonic band-edge-induced enhancement in absorption and emission
NASA Astrophysics Data System (ADS)
Ummer, Karikkuzhi Variyath; Vijaya, Ramarao
2015-01-01
An enhancement in photonic band-edge-induced absorption and emission from rhodamine-B dye doped polystyrene pseudo gap photonic crystals is studied. The band-edge-induced enhancement in absorption is achieved by selecting the incident angle of the excitation beam so that the absorption spectrum of the emitter overlaps the photonic band edge. The band-edge-induced enhancement in emission, on the other hand, is possible with and without an enhancement in band-edge-induced absorption, depending on the collection angle of emission. Through a simple set of measurements with suitably chosen angles for excitation and emission, we achieve a maximum enhancement of 70% in emission intensity with band-edge-induced effects over and above the intrinsic emission in the case of self-assembled opals. This is a comprehensive effort to interpret tunable lasing in opals as well as to predict the wavelength of lasing arising as a result of band-edge-induced distributed feedback effects.
Special purpose modes in photonic band gap fibers
Spencer, James; Noble, Robert; Campbell, Sara
2013-04-02
Photonic band gap fibers are described having one or more defects suitable for the acceleration of electrons or other charged particles. Methods and devices are described for exciting special purpose modes in the defects including laser coupling schemes as well as various fiber designs and components for facilitating excitation of desired modes. Results are also presented showing effects on modes due to modes in other defects within the fiber and due to the proximity of defects to the fiber edge. Techniques and devices are described for controlling electrons within the defect(s). Various applications for electrons or other energetic charged particles produced by such photonic band gap fibers are also described.
Quantum interference of independently generated telecom-band single photons
Patel, Monika; Altepeter, Joseph B.; Huang, Yu-Ping; Oza, Neal N.; Kumar, Prem
2014-12-04
We report on high-visibility quantum interference of independently generated telecom O-band (1310 nm) single photons using standard single-mode fibers. The experimental data are shown to agree well with the results of simulations using a comprehensive quantum multimode theory without the need for any fitting parameter.
W-band active imaging by photonics-based synthesizer
NASA Astrophysics Data System (ADS)
Kanno, Atsushi; Sekine, Norihiko; Kasamatsu, Akifumi; Yamamoto, Naokatsu
2016-05-01
We demonstrate a nondestructive electromagnetic-wave imaging system with a photonics-based W-band synthe- sizer, traveling-wave tube amplifier and focal-plane transistor array in real time manner. High-power amplifier with multi-watts output will enhance the quality of obtained images under transmission and reflection imaging configurations.
Photonic Band Gap structures: A new approach to accelerator cavities
Kroll, N. |; Smith, D.R.; Schultz, S.
1992-12-31
We introduce a new accelerator cavity design based on Photonic Band Gap (PGB) structures. The PGB cavity consists of a two-dimensional periodic array of high dielectric, low loss cylinders with a single removal defect, bounded on top and bottom by conducting sheets. We present the results of both numerical simulations and experimental measurements on the PGB cavity.
Analysis of tunable photonic band structure in an extrinsic plasma photonic crystal
NASA Astrophysics Data System (ADS)
King, Tzu-Chyang; Yang, Chih-Chiang; Hsieh, Pei-Hung; Chang, Tsung-Wen; Wu, Chien-Jang
2015-03-01
In this work, we theoretically investigate the tunable photonic band structure (PBS) for an extrinsic plasma photonic crystal (PPC). The extrinsic PPC is made of a bulk cold plasma layer which is influenced by an externally periodic static magnetic field. The PBS can be tuned by the variation of the magnitude of externally applied magnetic field. In addition, we also show that the PBS can be changed as a function of the electron density as well as the thickness variation.
Optical properties of silver nanocomposites and photonic band gap - Pressure dependence
NASA Astrophysics Data System (ADS)
Ramanujam, N. R.; Wilson, K. S. Joseph
2016-06-01
We theoretically investigate the effect of photonic band gaps in one dimensional photonic crystals based on nanocomposite of silver nanoparticles. The dielectric permittivity is computed based on the pressure dependence of plasma frequency and damping constant of silver nanoparticle. It leads to the tuning of photonic band gap. We have also investigated the change in photonic band gap due to the influence of filling factor and the size of the nanoparticles. Our results provide a guideline for designing potential photonic devices.
Photonic Band Gap resonators for high energy accelerators
Schultz, S.; Smith, D.R.; Kroll, N. |
1993-12-31
We have proposed that a new type of microwave resonator, based on Photonic Band Gap (PBG) structures, may be particularly useful for high energy accelerators. We provide an explanation of the PBG concept and present data which illustrate some of the special properties associated with such structures. Further evaluation of the utility of PBG resonators requires laboratory testing of model structures at cryogenic temperatures, and at high fields. We provide a brief discussion of our test program, which is currently in progress.
Perina, Jan Jr.; Centini, Marco; Sibilia, Concita; Bertolotti, Mario; Scalora, Michael
2006-03-15
We have developed a rigorous quantum model of spontaneous parametric down-conversion in a nonlinear 1D photonic-band-gap structure based upon expansion of the field into monochromatic plane waves. The model provides a two-photon amplitude of a created photon pair. The spectra of the signal and idler fields, their intensity profiles in the time domain, as well as the coincidence-count interference pattern in a Hong-Ou-Mandel interferometer are determined both for cw and pulsed pumping regimes in terms of the two-photon amplitude. A broad range of parameters characterizing the emitted down-converted fields can be used. As an example, a structure composed of 49 layers of GaN/AlN is analyzed as a suitable source of photon pairs having high efficiency.
Photonic Crystal and Photonic Band-Gap Structures for Light Extraction and Emission Control
NASA Astrophysics Data System (ADS)
de La Rue, Richard M.
Research into photonic crystal (PhC) and photonic band-gap (PBG) structures has been motivated, from the start, by their possible use in controlling, modifying and enhancing the light emission process from high refractive index solid materials. This chapter considers the possible role of such structures when incorporated into semiconductor diode based light-emitting devices. Both light-emitting diodes (LEDs) and lasers will be considered. In order to provide a proper framework for discussion and analysis, space is devoted to the historical development of III-V semiconductor based LEDs — and to competing alternative approaches that have been demonstrated for enhanced light extraction. The possible advantages of photonic quasi-crystal (PQC) structures over regularly periodic photon crystal structures for advanced LED designs are also considered. Photonic crystal structures potentially provide major enhancements in the performance of laser diodes (LDs) — and progress towards this performance enhancement will be reviewed.
NASA Astrophysics Data System (ADS)
Le, Zichun; Yang, Yang; Quan, Bisheng; Wang, Weibiao; Wang, Xiaoxiao; Chi, Yongjiang; Ma, Lingfang
2005-01-01
Photonic crystals have been widely studied in the fields of physics, material science and optical information technology. In general, the standard rectangular finite difference time domain (FDTD) method is used to predict the performances of photonic crystals. It is however very time consuming and inefficient. The current authors developed a software called GCFE, which is based on a non-orthogonal FDTD method. The software can be used to predict the photonic band structures, photonic states density and transmission and/or reflection coefficients for one-dimensional to three-dimensional photonic crystals. In the present paper, the derivations of the discrete Maxwell"s equations in time-domain and space-domain and the derivation of the discrete transfer matrix in real-space domain are briefly described firstly. In addition, the design idea and the functions of GCFE version 2.0.00 are introduced. Moreover, the band structures, transmission and reflection coefficients and photonic states density for the photonic crystal with cube lattice are calculated by our GCFE software, and numerical application results are also shown.
Hollow-Core Photonic Band Gap Fibers for Particle Acceleration
Noble, Robert J.; Spencer, James E.; Kuhlmey, Boris T.; /Sydney U.
2011-08-19
Photonic band gap (PBG) dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM) accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller holes to confine the mode, forming a photonic crystal fiber in which modes exist in frequency pass-bands, separated by band gaps. The hollow core acts as a defect which breaks the crystal symmetry, and so-called defect, or trapped modes having frequencies in the band gap will only propagate near the defect. We describe the design of 2-D hollow-core PBG fibers to support TM defect modes with high longitudinal fields and high characteristic impedance. Using as-built dimensions of industrially-made fibers, we perform a simulation analysis of the first prototype PBG fibers specifically designed to support speed-of-light TM modes.
Dual-band photon sorting plasmonic MIM metamaterial sensor
NASA Astrophysics Data System (ADS)
Jung, Young Uk; Bendoym, Igor; Golovin, Andrii B.; Crouse, David T.
2014-06-01
We propose plasmonic metal-insulator-metal (MIM) metamaterial designs for the sensing of two infrared wavelength bands, the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) band by using a photon sorting technique. The proposed structures can capture light effectively on the metasurfaces based on coupling of free space energy to a subwavelength plasmonic mode. Photon sorting can be performed such that the incident light with a broad spectrum upon the metasurfaces can be "split" according to wavelength, channeling different spectral bands to different physical regions of the array on the surface where it is then absorbed by the insulator. Two different structures described in this work are (1) Square-type structure which consists of MIM resonators being periodically arranged to form a polarization independent sensor and (2) Meander-type structure which consists of MIM resonators being connected to form the meander shaped sensor. Mercury Cadmium Telluride (HgCdTe) posts are used as absorbing material within the MIM structure to generate free carriers and allow for collection of carrier charges. The proposed structures have compact designs and exhibit efficient light splitting and absorption for the IR spectral band. Structural and material properties, the electric field distribution and Poynting vector fields at the resonance frequencies are provided. Applications include thermal imaging, night vision systems, rifle sights, missile detection and discrimination, dual bandwidth optical filters, light trapping, and electromagnetically induced transparency.
Band gaps of two-dimensional antiferromagnetic photonic crystal
NASA Astrophysics Data System (ADS)
Song, Yu-Ling; Ta, Jin-Xing; Wang, Xuan-Zhang
2011-07-01
In an external magnetic field, the band structure of a two-dimensional photonic crystal (PC) composed of parallel antiferromagnetic cylinders in a background dielectric is investigated with a Green's function method. The cylinders with two resonant frequencies form a square lattice and are characterized by a magnetic permeability tensor. In our numerical calculation, we find that this method allows fast convergence and is available in both the resonant and non-resonant frequency ranges. In the non-resonant range, the PC is similar in band structure to an ordinary dielectric PC. Two electromagnetic band gaps, however, appear in the resonant frequency region, and their frequency positions and widths are governed by the external field. The dependence of the electromagnetic gaps on the cylinder radius also is discussed.
NASA Astrophysics Data System (ADS)
Vargas, W. E.; Hernández-Jiménez, M.; Libby, E.; Azofeifa, D. E.; Solis, Á.; Barboza-Aguilar, C.
2015-09-01
Under normal illumination with non-polarized light, reflection spectra of the cuticle of golden-like and red Chrysina aurigans scarabs show a structured broad band of left-handed circularly polarized light. The polarization of the reflected light is attributed to a Bouligand-type left-handed chiral structure found through the scarab's cuticle. By considering these twisted structures as one-dimensional photonic crystals, a novel approach is developed from the dispersion relation of circularly polarized electromagnetic waves traveling through chiral media, to show how the broad band characterizing these spectra arises from an intrinsic narrow photonic band gap whose spectral position moves through visible and near-infrared wavelengths.
Zhang Haifeng; Liu Shaobin; Kong Xiangkun
2012-12-15
In this paper, the properties of photonic band gaps and dispersion relations of one-dimensional magnetized plasma photonic crystals composed of dielectric and magnetized plasma layers with arbitrary magnetic declination are theoretically investigated for TM polarized wave based on transfer matrix method. As TM wave propagates in one-dimensional magnetized plasma photonic crystals, the electromagnetic wave can be divided into two modes due to the influence of Lorentz force. The equations for effective dielectric functions of such two modes are theoretically deduced, and the transfer matrix equation and dispersion relations for TM wave are calculated. The influences of relative dielectric constant, plasma collision frequency, incidence angle, plasma filling factor, the angle between external magnetic field and +z axis, external magnetic field and plasma frequency on transmission, and dispersion relation are investigated, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that plasma collision frequency cannot change the locations of photonic band gaps for both modes, and also does not affect the reflection and transmission magnitudes. The characteristics of photonic band gaps for both modes can be obviously tuned by relative dielectric constant, incidence angle, plasma filling factor, the angle between external magnetic field and +z axis, external magnetic field and plasma frequency, respectively. These results would provide theoretical instructions for designing filters, microcavities, and fibers, etc.
Isotropic band gaps and freeform waveguides observed in hyperuniform disordered photonic solids
Man, Weining; Florescu, Marian; Williamson, Eric Paul; He, Yingquan; Hashemizad, Seyed Reza; Leung, Brian Y. C.; Liner, Devin Robert; Torquato, Salvatore; Chaikin, Paul M.; Steinhardt, Paul J.
2013-01-01
Recently, disordered photonic media and random textured surfaces have attracted increasing attention as strong light diffusers with broadband and wide-angle properties. We report the experimental realization of an isotropic complete photonic band gap (PBG) in a 2D disordered dielectric structure. This structure is designed by a constrained optimization method, which combines advantages of both isotropy due to disorder and controlled scattering properties due to low-density fluctuations (hyperuniformity) and uniform local topology. Our experiments use a modular design composed of Al2O3 walls and cylinders arranged in a hyperuniform disordered network. We observe a complete PBG in the microwave region, in good agreement with theoretical simulations, and show that the intrinsic isotropy of this unique class of PBG materials enables remarkable design freedom, including the realization of waveguides with arbitrary bending angles impossible in photonic crystals. This experimental verification of a complete PBG and realization of functional defects in this unique class of materials demonstrate their potential as building blocks for precise manipulation of photons in planar optical microcircuits and has implications for disordered acoustic and electronic band gap materials. PMID:24043795
Isotropic band gaps and freeform waveguides observed in hyperuniform disordered photonic solids.
Man, Weining; Florescu, Marian; Williamson, Eric Paul; He, Yingquan; Hashemizad, Seyed Reza; Leung, Brian Y C; Liner, Devin Robert; Torquato, Salvatore; Chaikin, Paul M; Steinhardt, Paul J
2013-10-01
Recently, disordered photonic media and random textured surfaces have attracted increasing attention as strong light diffusers with broadband and wide-angle properties. We report the experimental realization of an isotropic complete photonic band gap (PBG) in a 2D disordered dielectric structure. This structure is designed by a constrained optimization method, which combines advantages of both isotropy due to disorder and controlled scattering properties due to low-density fluctuations (hyperuniformity) and uniform local topology. Our experiments use a modular design composed of Al2O3 walls and cylinders arranged in a hyperuniform disordered network. We observe a complete PBG in the microwave region, in good agreement with theoretical simulations, and show that the intrinsic isotropy of this unique class of PBG materials enables remarkable design freedom, including the realization of waveguides with arbitrary bending angles impossible in photonic crystals. This experimental verification of a complete PBG and realization of functional defects in this unique class of materials demonstrate their potential as building blocks for precise manipulation of photons in planar optical microcircuits and has implications for disordered acoustic and electronic band gap materials. PMID:24043795
Unfolding the band structure of non-crystalline photonic band gap materials
Tsitrin, Samuel; Williamson, Eric Paul; Amoah, Timothy; Nahal, Geev; Chan, Ho Leung; Florescu, Marian; Man, Weining
2015-01-01
Non-crystalline photonic band gap (PBG) materials have received increasing attention, and sizeable PBGs have been reported in quasi-crystalline structures and, more recently, in disordered structures. Band structure calculations for periodic structures produce accurate dispersion relations, which determine group velocities, dispersion, density of states and iso-frequency surfaces, and are used to predict a wide-range of optical phenomena including light propagation, excited-state decay rates, temporal broadening or compression of ultrashort pulses and complex refraction phenomena. However, band calculations for non-periodic structures employ large super-cells of hundreds to thousands building blocks, and provide little useful information other than the PBG central frequency and width. Using stereolithography, we construct cm-scale disordered PBG materials and perform microwave transmission measurements, as well as finite-difference time-domain (FDTD) simulations. The photonic dispersion relations are reconstructed from the measured and simulated phase data. Our results demonstrate the existence of sizeable PBGs in these disordered structures and provide detailed information of the effective band diagrams, dispersion relation, iso-frequency contours, and their angular dependence. Slow light phenomena are also observed in these structures near gap frequencies. This study introduces a powerful tool to investigate photonic properties of non-crystalline structures and provides important effective dispersion information, otherwise difficult to obtain. PMID:26289434
Unfolding the band structure of non-crystalline photonic band gap materials
NASA Astrophysics Data System (ADS)
Tsitrin, Samuel; Williamson, Eric Paul; Amoah, Timothy; Nahal, Geev; Chan, Ho Leung; Florescu, Marian; Man, Weining
2015-08-01
Non-crystalline photonic band gap (PBG) materials have received increasing attention, and sizeable PBGs have been reported in quasi-crystalline structures and, more recently, in disordered structures. Band structure calculations for periodic structures produce accurate dispersion relations, which determine group velocities, dispersion, density of states and iso-frequency surfaces, and are used to predict a wide-range of optical phenomena including light propagation, excited-state decay rates, temporal broadening or compression of ultrashort pulses and complex refraction phenomena. However, band calculations for non-periodic structures employ large super-cells of hundreds to thousands building blocks, and provide little useful information other than the PBG central frequency and width. Using stereolithography, we construct cm-scale disordered PBG materials and perform microwave transmission measurements, as well as finite-difference time-domain (FDTD) simulations. The photonic dispersion relations are reconstructed from the measured and simulated phase data. Our results demonstrate the existence of sizeable PBGs in these disordered structures and provide detailed information of the effective band diagrams, dispersion relation, iso-frequency contours, and their angular dependence. Slow light phenomena are also observed in these structures near gap frequencies. This study introduces a powerful tool to investigate photonic properties of non-crystalline structures and provides important effective dispersion information, otherwise difficult to obtain.
Unfolding the band structure of non-crystalline photonic band gap materials.
Tsitrin, Samuel; Williamson, Eric Paul; Amoah, Timothy; Nahal, Geev; Chan, Ho Leung; Florescu, Marian; Man, Weining
2015-01-01
Non-crystalline photonic band gap (PBG) materials have received increasing attention, and sizeable PBGs have been reported in quasi-crystalline structures and, more recently, in disordered structures. Band structure calculations for periodic structures produce accurate dispersion relations, which determine group velocities, dispersion, density of states and iso-frequency surfaces, and are used to predict a wide-range of optical phenomena including light propagation, excited-state decay rates, temporal broadening or compression of ultrashort pulses and complex refraction phenomena. However, band calculations for non-periodic structures employ large super-cells of hundreds to thousands building blocks, and provide little useful information other than the PBG central frequency and width. Using stereolithography, we construct cm-scale disordered PBG materials and perform microwave transmission measurements, as well as finite-difference time-domain (FDTD) simulations. The photonic dispersion relations are reconstructed from the measured and simulated phase data. Our results demonstrate the existence of sizeable PBGs in these disordered structures and provide detailed information of the effective band diagrams, dispersion relation, iso-frequency contours, and their angular dependence. Slow light phenomena are also observed in these structures near gap frequencies. This study introduces a powerful tool to investigate photonic properties of non-crystalline structures and provides important effective dispersion information, otherwise difficult to obtain. PMID:26289434
Modeling of Photonic Band Gap Crystals and Applications
Ihab Fathy El-Kady
2002-08-27
In this work, the authors have undertaken a theoretical approach to the complex problem of modeling the flow of electromagnetic waves in photonic crystals. The focus is to address the feasibility of using the exciting phenomena of photonic gaps (PBG) in actual applications. The authors start by providing analytical derivations of the computational electromagnetic methods used in their work. They also present a detailed explanation of the physics underlying each approach, as well as a comparative study of the strengths and weaknesses of each method. The Plane Wave expansion, Transfer Matrix, and Finite Difference time Domain Methods are addressed. They also introduce a new theoretical approach, the Modal Expansion Method. They then shift the attention to actual applications. They begin with a discussion of 2D photonic crystal wave guides. The structure addressed consists of a 2D hexagonal structure of air cylinders in a layered dielectric background. Comparison with the performance of a conventional guide is made, as well as suggestions for enhancing it. The studies provide an upper theoretical limit on the performance of such guides, as they assumed no crystal imperfections and non-absorbing media. Next, they study 3D metallic PBG materials at near infrared and optical wavelengths. The main objective is to study the importance of absorption in the metal and the suitability of observing photonic band gaps in such structures. They study simple cubic structures where the metallic scatters are either cubes or interconnected metallic rods. Several metals are studied (aluminum, gold, copper, and silver). The effect of topology is addressed and isolated metallic cubes are found to be less lossy than the connected rod structures. The results reveal that the best performance is obtained by choosing metals with a large negative real part of the dielectric function, together with a relatively small imaginary part. Finally, they point out a new direction in photonic crystal
On the completeness of photon-added coherent states
NASA Astrophysics Data System (ADS)
Sixdeniers, J.-M.; Penson, K. A.
2001-04-01
We demonstrate explicitly the completeness of photon-added coherent states (PACSs), introduced by Agarwal and Tara (Agarwal G S and Tara K 1991 Phys. Rev. A 43 492) and defined, up to normalization, by (†)M|z>, M = 0,1,2,...,, where † is the boson creation operator and |z> are conventional Glauber-Klauder coherent states. We find the analytical form of the positive weight function in their resolution of unity by solving the associated Stieltjes power-moment problem. We furnish an example of generation of another set of PACSs which are complete.
Introducing Defects in Photonic Band-Gap (PBG) Crystals
Johnson, Elliott C.; /North Dakota State U. /SLAC
2007-11-07
Photonic Band-Gap (PBG) fibers are a periodic array of optical materials arranged in a lattice called a photonic crystal. The use of PBG fibers for particle acceleration is being studied by the Advanced Accelerator Research Department (AARD) at SLAC. By introducing defects in such fibers, e.g. removing one or more capillaries from a hexagonal lattice, spatially confined modes suitable for particle acceleration may be created. The AARD has acquired several test samples of PBG fiber arrays with varying refractive index, capillary size, and length from an external vendor for testing. The PBGs were inspected with a microscope and characteristics of the capillaries including radii, spacing, and errors in construction were determined. Transmission tests were performed on these samples using a broad-range spectrophotometer. In addition, detailed E-field simulations of different PBG configurations were done using the CUDOS and RSOFT codes. Several accelerating modes for different configurations were found and studied in detail.
NASA Astrophysics Data System (ADS)
Jena, S.; Tokas, R. B.; Sarkar, P.; Haque, S. Maidul; Misal, J. S.; Rao, K. D.; Thakur, S.; Sahoo, N. K.
2015-06-01
The multilayer structure of TiO2/SiO2 (11 layers) as one dimensional photonic crystal (1D PC) has been designed and then fabricated by using asymmetric bipolar pulse DC magnetron sputtering technique for omnidirectional photonic band gap. The experimentally measured photonic band gap (PBG) in the visible region is well matched with the theoretically calculated band structure (ω vs. k) diagram. The experimentally measured omnidirectional reflection band of 44 nm over the incident angle range of 0°-70° is found almost matching within the theoretically calculated band.
Nonlinear Bloch waves in metallic photonic band-gap filaments
Kaso, Artan; John, Sajeev
2007-11-15
We demonstrate the occurrence of nonlinear Bloch waves in metallic photonic crystals (PCs). These periodically structured filaments are characterized by an isolated optical pass band below an effective plasma gap. The pass band occurs in a frequency range where the metallic filament exhibits a negative, frequency-dependent dielectric function and absorption loss. The metallic losses are counterbalanced by gain in two models of inhomogeneously broadened nonlinear oscillators. In the first model, we consider close-packed quantum dots that fill the void regions of a two-dimensional (2D) metallic PC, and whose inhomogeneously broadened emission spectrum spans the original optical pass band of the bare filament. In the second model, we consider thin (10-50 nm) layers of inhomogeneously broadened two-level resonators, with large dipole oscillator strength, that cover the interior surfaces of 2D metallic (silver and tungsten) PCs. These may arise from localized surface plasmon resonances due to small metal particles or an otherwise rough metal surface. For simplicity, we treat electromagnetic modes with electric field perpendicular to the plane of metal periodicity. In both models, a pumping threshold of the resonators is found, above which periodic nonlinear solutions of Maxwell's equations with purely real frequency within the optical pass band emerge. These nonlinear Bloch waves exhibit a laserlike input pumping to output amplitude characteristic. For strong surface resonances, these nonlinear waves may play a role in light emission from a hot tungsten (suitably microstructured) filament.
NASA Astrophysics Data System (ADS)
Kim, Seong-Han; Kim, Soeun; Kee, Chul-Sik
2016-08-01
Photonic crystals composed of virtual pillars with magnetic walls are proposed. A virtual pillar with a magnetic wall can be created inside a parallel perfect electric conductor plate waveguide by introducing a circular perfect magnetic conductor patch in the upper perfect electric conductor plate of the waveguide. The virtual pillar mimics a perfect magnetic conductor pillar with a radius less than that of the circular patch because electromagnetic waves can slightly penetrate the wall. Furthermore, the photonic band structures of a triangular photonic crystal composed of virtual pillars for the transverse electromagnetic modes of the waveguide are investigated. They are very similar to those of a triangular photonic crystal composed of infinitely long perfect electric conductor cylinders for transverse magnetic modes. The similarity between the two different photonic crystals is well understood by the boundary conditions of perfect electric and magnetic conductor surfaces. A double Dirac cone at the center of the Brillouin zone is observed and thus the virtual pillar triangular photonic crystal can act a zero-refractive-index material at the Dirac point frequency.
Gerrits, Thomas; Lita, Adriana E.; Calkins, Brice; Tomlin, Nathan A.; Fox, Anna E.; Linares, Antia Lamas; Mirin, Richard P.; Nam, Sae Woo; Thomas-Peter, Nicholas; Metcalf, Benjamin J.; Spring, Justin B.; Langford, Nathan K.; Walmsley, Ian A.; Gates, James C.; Smith, Peter G. R.
2011-12-15
Integration is currently the only feasible route toward scalable photonic quantum processing devices that are sufficiently complex to be genuinely useful in computing, metrology, and simulation. Embedded on-chip detection will be critical to such devices. We demonstrate an integrated photon-number-resolving detector, operating in the telecom band at 1550 nm, employing an evanescently coupled design that allows it to be placed at arbitrary locations within a planar circuit. Up to five photons are resolved in the guided optical mode via absorption from the evanescent field into a tungsten transition-edge sensor. The detection efficiency is 7.2{+-}0.5 %. The polarization sensitivity of the detector is also demonstrated. Detailed modeling of device designs shows a clear and feasible route to reaching high detection efficiencies.
Photon Temporal Modes: A Complete Framework for Quantum Information Science
NASA Astrophysics Data System (ADS)
Brecht, B.; Reddy, Dileep V.; Silberhorn, C.; Raymer, M. G.
2015-10-01
Field-orthogonal temporal modes of photonic quantum states provide a new framework for quantum information science (QIS). They intrinsically span a high-dimensional Hilbert space and lend themselves to integration into existing single-mode fiber communication networks. We show that the three main requirements to construct a valid framework for QIS—the controlled generation of resource states, the targeted and highly efficient manipulation of temporal modes, and their efficient detection—can be fulfilled with current technology. We suggest implementations of diverse QIS applications based on this complete set of building blocks.
Wide-Band Microwave Receivers Using Photonic Processing
NASA Technical Reports Server (NTRS)
Matsko, Andrey; Maleki, Lute; Itchenko, Vladimir; Yu, Nan; Strekalov, Dmitry; Savchenkov, Anatoliy
2008-01-01
In wide-band microwave receivers of a type now undergoing development, the incoming microwave signals are electronically preamplified, then frequency-up-converted to optical signals that are processed photonically before being detected. This approach differs from the traditional approach, in which incoming microwave signals are processed by purely electronic means. As used here, wide-band microwave receivers refers especially to receivers capable of reception at any frequency throughout the range from about 90 to about 300 GHz. The advantage expected to be gained by following the up-conversion-and-photonic-processing approach is the ability to overcome the limitations of currently available detectors and tunable local oscillators in the frequency range of interest. In a receiver following this approach (see figure), a preamplified incoming microwave signal is up-converted by the method described in the preceeding article. The frequency up-converter exploits the nonlinearity of the electromagnetic response of a whispering gallery mode (WGM) resonator made of LiNbO3. Up-conversion takes place by three-wave mixing in the resonator. The WGM resonator is designed and fabricated to function simultaneously as an electro-optical modulator and to exhibit resonance at the microwave and optical operating frequencies plus phase matching among the microwave and optical signals circulating in the resonator. The up-conversion is an efficient process, and the efficiency is enhanced by the combination of microwave and optical resonances. The up-converted signal is processed photonically by use of a tunable optical filter or local oscillator, and is then detected. Tunable optical filters can be made to be frequency agile and to exhibit high resonance quality factors (high Q values), thereby making it possible to utilize a variety of signal-processing modalities. Therefore, it is anticipated that when fully developed, receivers of this type will be compact and will be capable of both
NASA Astrophysics Data System (ADS)
Wang, H.; Yang, Z. Y.; Lu, Y. F.
2007-02-01
Laser-assisted chemical vapor deposition was applied in fabricating three-dimensional (3D) spherical-shell photonic band gap (PBG) structures by depositing silicon shells covering silica particles, which had been self-assembled into 3D colloidal crystals. The colloidal crystals of self-assembled silica particles were formed on silicon substrates using the isothermal heating evaporation approach. A continuous wave Nd:YAG laser (1064nm wavelength) was used to deposit silicon shells by thermally decomposing disilane gas. Periodic silicon-shell/silica-particle PBG structures were obtained. By removing the silica particles enclosed in the silicon shells using hydrofluoric acid, hollow spherical silicon-shell arrays were produced. This technique is capable of fabricating structures with complete photonic band gaps, which is predicted by simulations with the plane wave method. The techniques developed in this study have the potential to flexibly engineer the positions of the PBGs by varying both the silica particle size and the silicon-shell thickness. Ellipsometry was used to investigate the specific photonic band gaps for both structures.
Observation of localized flat-band modes in a quasi-one-dimensional photonic rhombic lattice.
Mukherjee, Sebabrata; Thomson, Robert R
2015-12-01
We experimentally demonstrate the photonic realization of a dispersionless flat band in a quasi-one-dimensional photonic lattice fabricated by ultrafast laser inscription. In the nearest neighbor tight binding approximation, the lattice supports two dispersive and one nondispersive (flat) band. We experimentally excite superpositions of flat-band eigenmodes at the input of the photonic lattice and show the diffractionless propagation of the input states due to their infinite effective mass. In the future, the use of photonic rhombic lattices, together with the successful implementation of a synthetic gauge field, will enable the observation of Aharonov-Bohm photonic caging. PMID:26625021
Recent progress on photonic band gap accelerator cavities
Smith, D.R.; Li, D.; Vier, D.C.
1997-02-01
We report on the current status of our program to apply Photonic Band Gap (PBG) concepts to produce novel high-energy, high-intensity accelerator cavities. The PBG design on which we have concentrated our initial efforts consists of a square array of metal cylinders, terminated by conducting or superconducting sheets, and surrounded by microwave absorber on the periphery of the structure. A removed cylinder from the center of the array constitutes a site defect where a localized electromagnetic mode can occur. In previous work, we have proposed that this structure could be utilized as an accelerator cavity, with advantageous properties over conventional cavity designs. In the present work, we present further studies, including MAFIA-based numerical calculations and experimental measurements, demonstrating the feasibility of using the proposed structure in a real accelerator application.
Martinez, Luis Javier; Alija, Alfonso Rodriguez; Postigo, Pablo Aitor; Galisteo-López, J F; Galli, Matteo; Andreani, Lucio Claudio; Seassal, Christian; Viktorovitch, Pierre
2008-06-01
We investigate the change of the photonic band structure of the Suzuki-phase photonic crystal lattice when the horizontal mirror symmetry is broken by an underlying Bragg reflector. The structure consists of an InP photonic crystal slab including four InAsP quantum wells, a SiO(2) bonding layer, and a bottom high index contrast Si/SiO(2) Bragg mirror deposited on a Si wafer. Angle- and polarization-resolved photoluminescence spectroscopy has been used for measuring the photonic band structure and for investigating the coupling to a polarized plane wave in the far field. A drastic change in the k-space photonic dispersion between the structure with and without Bragg reflector is measured. An important enhancement on the photoluminescence emission up to seven times has been obtained for a nearly flat photonic band, which is characteristic of the Suzuki-phase lattice. PMID:18545565
Wake-field studies on photonic band gap accelerator cavities
NASA Astrophysics Data System (ADS)
Li, Derun; Kroll, N.; Smith, D. R.; Schultz, S.
1997-03-01
We have studied the wake-field of several metal Photonic Band Gap (PBG) cavities which consist of either a square or a hexagonal array of metal cylinders, bounded on top and bottom by conducting or superconducting sheets, surrounded by placing microwave absorber at the periphery or by replacing outer rows of metal cylinders with lossy dielectric ones, or by metallic walls. A removed cylinder from the center of the array constitutes a site defect where a localized electromagnetic mode can occur. While both monopole and dipole wake-fields have been studied, we confine our attention here mainly to the dipole case. The dipole wake-field is produced by modes in the propagation bands which tend to fill the entire cavity more or less uniformly and are thus easy to damp selectively. MAFIA time domain simulation of the transverse wake-field has been compared with that of a cylindrical pill-box comparison cavity. Even without damping the wake-field of the metal PBG cavity is substantially smaller than that of the pill-box cavity and may be further reduced by increasing the size of the lattice. By introducing lossy material at the periphery we have been able to produce Q factors for the dipole modes in the 40 to 120 range without significantly degrading the accelerating mode.
NASA Astrophysics Data System (ADS)
Labbani, Amel; Benghalia, Abdelmadjid
2012-06-01
Using the Maxwell-Garnett theory, the evolution of the refractive index of titanium dioxide (TiO2) doped with zinc sulfide (ZnS) particles is presented. The presence of the nano-objects in the host matrix allows us to obtain a new composite material with tunable optical properties. We find that the filling factor of ZnS nanoparticles greatly alters photonic band gaps (PBGs). We have calculated also the photonic band structure for electromagnetic waves propagating in a structure consisting of ZnS rods covered with the air shell layer in 2D hexagonal and square lattices by the finite difference time domain (FDTD) method. The rods are embedded in the TiO2 background medium with a high dielectric constant. Such photonic lattices present complete photonic band gaps (CPBGs). Our results show that the existence of the air shell layer leads to larger complete photonic gaps. We believe that the present results are significant to increase the possibilities for experimentalists to realize a sizeable and larger CPBG.
The Photonic Band Gaps in the Two-Dimensional Plasma Photonic Crystals with Rhombus Lattice
NASA Astrophysics Data System (ADS)
Zhang, Kaiming; Sun, Dongsheng
2016-06-01
In this paper, under two different electromagnetic modes, the photonic band gaps (PBGs) in the two-dimensional plasma photonic crystals (PPCs) are theoretically investigated based on the plane wave expansion method. The proposed PPCs are arranged in rhombus lattices, in which the homogeneous unmagnetized plasma rods are immersed in the isotropic dielectric background. The computed results showed that PBGs can be easily tuned by the angle of rhombus lattices, and a cutoff frequency and a flatbands region can be observed under the TM and TE polarized waves, respectively. The relationships between the relative bandwidths of first PBGs and the parameters of PPCs in two such cases also are discussed. The numerical simulations showed that the PBGs can be manipulated obviously by the parameters as mentioned above. The proposed results can be used to design the waveguide and filter based on the PPCs.
Photonic band structures of one-dimensional photonic crystals doped with plasma
NASA Astrophysics Data System (ADS)
Guo, B.; Xie, M. Q.; Peng, L.
2012-07-01
The photonic band structures (PBSs) of oblique incidence propagation in one-dimensional plasma-doped photonic crystals (PCs) are investigated carefully. When the lattice constant of plasma-doped PCs is less than the incident wavelength, the PC becomes anisotropic. Therefore, the dielectric constant of PC is converted into a complex tensor dielectric constant. This determines the PBSs of PCs. In the present paper, one-dimensional PCs are taken as an example to study both normal and absorption PBSs. Using both the effective medium approximation and the transfer matrix method, we can derive the dispersion relation for PCs. The dependence of the plasma filling factor on the effective dielectric constant and PBSs is calculated and discussed.
Pavarini, E; Andreani, L C
2002-09-01
The photonic band dispersion and density of states (DOS) are calculated for the three-dimensional (3D) hexagonal structure corresponding to a distributed Bragg reflector patterned with a 2D triangular lattice of circular holes. Results for the Si/SiO(2) and GaAs/Al(x)Ga(1-x)As systems determine the optimal parameters for which a gap in the 2D plane occurs and overlaps the 1D gap of the multilayer. The DOS is considerably reduced in correspondence with the overlap of 2D and 1D gaps. Also, the local density of states (i.e., the DOS weighted with the squared electric field at a given point) has strong variations depending on the position. Both results imply substantial changes of spontaneous emission rates and patterns for a local emitter embedded in the structure and make this system attractive for the fabrication of a 3D photonic crystal with controlled radiative properties. PMID:12366275
Design and testing of photonic band gap channel-drop-filters
Shchegolkov, Dmitry; Earley, Lawrence M; Health, Cynthia E; Smirnova, Evgenya I
2009-01-01
We have designed, fabricated and tested several novel passive mm-wave spectrometers based on Photonic Band Gap (PBG) structures. Our spectrometers were designed to operate in the frequency ranges of 90-130 and 220-300 GHz. We built and tested both metallic and dielectric silicon Channel-Drop-Filter (CDF) structures at 90-130 GHz. We are currently fabricating a dielectric CDF structure to operate at 220-300 GHz. The complete recent test results for the metal version and preliminary test results for the higher frequency silicon versions will be presented at the conference.
Geometric phase and entanglement of Raman photon pairs in the presence of photonic band gap
Berrada, K.; Ooi, C. H. Raymond; Abdel-Khalek, S.
2015-03-28
Robustness of the geometric phase (GP) with respect to different noise effects is a basic condition for an effective quantum computation. Here, we propose a useful quantum system with real physical parameters by studying the GP of a pair of Stokes and anti-Stokes photons, involving Raman emission processes with and without photonic band gap (PBG) effect. We show that the properties of GP are very sensitive to the change of the Rabi frequency and time, exhibiting collapse phenomenon as the time becomes significantly large. The system allows us to obtain a state which remains with zero GP for longer times. This result plays a significant role to enhance the stabilization and control of the system dynamics. Finally, we investigate the nonlocal correlation (entanglement) between the pair photons by taking into account the effect of different parameters. An interesting correlation between the GP and entanglement is observed showing that the PBG stabilizes the fluctuations in the system and makes the entanglement more robust against the change of time and frequency.
Xu, Wen; Bai, Xue; Zhu, Yongsheng; Liu, Tong; Xu, Sai; Dong, Biao; Song, Hongwei
2013-05-14
Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition. PMID:23676019
NASA Astrophysics Data System (ADS)
Xu, Wen; Bai, Xue; Zhu, Yongsheng; Liu, Tong; Xu, Sai; Dong, Biao; Song, Hongwei
2013-05-01
Changes in the excitation spectra of luminescent species inserted in photorefractive crystals as a function of changes in the high-order photonic band gap (PBG) have not been previously observed. In this communication, we present our results monitoring the excitation band of Eu(TTA)3(TPPO)2 inserted in the PMMA opal photonic crystals as a function of the changes in the high-order PBG of the crystals. We find shifts in the complex excitation band and changes in the integrated emission intensity that correlates with shifts in the high-order PBG through coupling to the excitation transition.
NASA Astrophysics Data System (ADS)
Arriaga, J.; Dobrzynski, L.; Djafari-Rouhani, B.
2008-09-01
One- and two-dimensional photonic crystals based on silicon with infiltrated liquid crystals are investigated in this paper. We show that the photonic band gap can be continuously tuned changing the orientation of the director of the liquid crystal. For the one-dimensional case, we considered arbitrary direction of propagation of the electromagnetic waves, and we show that it is possible to tune the photonic band gap by an adequate orientation of the liquid crystal. For the two-dimensional case and propagation in the plane of periodicity, we show that there exists no complete photonic band gap in the system for both polarizations. We consider two different configurations, square array of solid Si cylinders in liquid crystal background and a triangular array of liquid crystal cylinders surrounded by Si. We show that for the triangular array it is possible to tune the photonic band gap only for the transversal electric modes. We used the plane wave expansion method to solve the Maxwell equations for anisotropic systems.
Sakai, Osamu; Sakaguchi, Takui; Tachibana, Kunihide
2007-04-01
Two theoretical approaches appropriate for two-dimensional plasma photonic crystals reveal dispersions of propagating waves including photonic (electromagnetic) band gaps and multiflatbands. A modified plane-wave expansion method yields dispersions of collisional periodical plasmas, and the complex-value solution of a wave equation by a finite difference method enables us to obtain dispersions with structure effects in an individual microplasma. Periodical plasma arrays form band gaps as well as normal photonic crystals, and multiflatbands are present below the electron plasma frequency in the transverse electric field mode. Electron elastic collisions lower the top frequency of the multiflatbands but have little effect on band gap properties. The spatial gradient of the local dielectric constant resulting from an electron density profile widens the frequency region of the multiflatbands, as demonstrated by the change of surface wave distributions. Propagation properties described in dispersions including band gaps and flatbands agree with experimental observations of microplasma arrays.
A 250 GHz Photonic Band Gap Gyrotron Amplifier
NASA Astrophysics Data System (ADS)
Nanni, Emilio A.; Lewis, Samantha M.; Shapiro, Michael A.; Temkin, Richard J.
2012-10-01
Initial results for a high power 250 GHz gyrotron traveling wave tube (gyro-TWT) amplifier will be presented. The amplifier uses a novel photonic band gap (PBG) interaction circuit that confines the TE03-like mode for operation. Stability from oscillations in lower order modes is provided by the PBG circuit. At 26.6 kV and 0.25 A the gyro-TWT operates with peak small signal gain of 27.3 dB at 251 GHz. The instantaneous -3 dB bandwidth of the amplifier at peak gain is 0.4 GHz. The amplifier can be tuned for operation from 245-254 GHz. A peak output power of 7.5 W has been measured. Experimental results taken over a wide range of parameters, 15-30 kV and 0.25-0.5 A, show good agreement with a theoretical model in the small signal gain regime. The theoretical model incorporates cold test measurements for the transmission line, input coupler, PBG waveguide and mode converter.
Photonic-Band-Gap Traveling-Wave Gyrotron Amplifier
Nanni, E. A.; Lewis, S. M.; Shapiro, M. A.; Griffin, R. G.; Temkin, R. J.
2014-01-01
We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and 45 W output power at 247.7 GHz with an instantaneous −3 dB bandwidth of 0.4 GHz. The amplifier can be tuned for operation from 245–256 GHz. The widest instantaneous −3 dB bandwidth of 4.5 GHz centered at 253.25 GHz was observed with a gain of 24 dB. The PBG circuit provides stability from oscillations by supporting the propagation of transverse electric (TE) modes in a narrow range of frequencies, allowing for the confinement of the operating TE03-like mode while rejecting the excitation of oscillations at nearby frequencies. This experiment achieved the highest frequency of operation for a gyrotron amplifier; at present, there are no other amplifiers in this frequency range that are capable of producing either high gain or high output power. This result represents the highest gain observed above 94 GHz and the highest output power achieved above 140 GHz by any conventional-voltage vacuum electron device based amplifier. PMID:24476286
Photonic-band-gap traveling-wave gyrotron amplifier.
Nanni, E A; Lewis, S M; Shapiro, M A; Griffin, R G; Temkin, R J
2013-12-01
We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and 45 W output power at 247.7 GHz with an instantaneous -3 dB bandwidth of 0.4 GHz. The amplifier can be tuned for operation from 245-256 GHz. The widest instantaneous -3 dB bandwidth of 4.5 GHz centered at 253.25 GHz was observed with a gain of 24 dB. The PBG circuit provides stability from oscillations by supporting the propagation of transverse electric (TE) modes in a narrow range of frequencies, allowing for the confinement of the operating TE03-like mode while rejecting the excitation of oscillations at nearby frequencies. This experiment achieved the highest frequency of operation for a gyrotron amplifier; at present, there are no other amplifiers in this frequency range that are capable of producing either high gain or high output power. This result represents the highest gain observed above 94 GHz and the highest output power achieved above 140 GHz by any conventional-voltage vacuum electron device based amplifier. PMID:24476286
Zhang, Hai-Feng; Liu, Shao-Bin; Kong, Xiang-Kun
2013-09-15
In this paper, the dispersive properties of three-dimensional (3D) magnetized plasma photonic crystals (MPPCs) composed of anisotropic dielectric (the uniaxial material) spheres immersed in homogeneous magnetized plasma background with face-centered-cubic (fcc) lattices are theoretically investigated by the plane wave expansion method, as the Voigt effects of magnetized plasma are considered. The equations for calculating the anisotropic photonic band gaps (PBGs) in the first irreducible Brillouin zone are theoretically deduced. The anisotropic PBGs and two flatbands regions can be obtained. The effects of the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency, and external magnetic field on the dispersive properties of the 3D MPPCs are investigated in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in 3D MPPCs with fcc lattices and the complete PBGs can be found compared to the conventional 3D MPPCs doped by the isotropic material. The bandwidths of PBGs can be tuned by introducing the magnetized plasma into 3D PCs containing the uniaxial material. It is also shown that the anisotropic PBGs can be manipulated by the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency, and external magnetic field, respectively. The locations of flatbands regions cannot be manipulated by any parameters except for the plasma frequency and external magnetic field. Introducing the uniaxial material can obtain the complete PBGs as the 3D MPPCs with high symmetry and also provides a way to design the tunable devices.
Fully confined photonic band gap and guided modes in a two-dimensional photonic crystal slab
Chow, K.C.; Lin, S.Y.; Johnson, S.G.; Villeneuve, P.R.; Joannopoulos, J.D.
1999-12-15
A new two-dimensional photonic crystal (2D PC) slab structure was created with a full three-dimensional light confinement. Guided modes with broad bandwidth and high transmission within the band gap are also observed. As an optical analog to electronic crystals, PC promises a revolution in the photonic world similar to the electronic revolution created by the electronic band gap engineering in semiconductor. 2D PC has an advantage of being easier to fabricate at optical wavelength ({lambda}) comparing with 3D PC. However, the light leakage in the vertical direction has been the main problem for using 2D PC in opto-electronic application. In this study, the authors solve this problem by combining traditional 2D PC with strong vertical index guiding between the waveguide layer (GaAs) and the cladding layer (Al{sub x}O{sub y}). A set of triangular lattice holes 2D PC's were fabricated with lattice constant a=460nm, hole diameter (d=0.6a) and waveguide layer thickness (t = 0.5a). Those parameters were chosen to maximize the TE photonic band gap (PBG) around {lambda} = 1.55{micro}m. The depth of etched holes is {approximately}0.6{micro}m and the 2{micro}m thick Al{sub x}O{sub y} cladding layer is obtained by thermal oxidation of Al{sub 0.9}Ga{sub 0.1}As. PC waveguides were also created by introducing line defects along {Gamma}K direction. The authors perform transmission measurement by coupling light to PC with 3{micro}m wide waveguides which extends {approximately}0.6mm on both sides of PC. An aspheric lens with NA = 0.4 is used to focus the collimated light from tunable diode laser into the input waveguide. Another identical lens is used to collect the transmitted light and focus to an infrared (IR) camera and a calibrated photo-detector with a beamsplitter. The Gaussian waveguide mode indicates that the signal detected by the photodetector comes only from the light interacting with PC and propagating along the waveguide. The absolute transmittance is obtained by
Integrable optical-fiber source of polarization-entangled photon pairs in the telecom band
Li Xiaoying; Liang Chuang; Fook Lee, Kim; Chen, Jun; Voss, Paul L.; Kumar, Prem
2006-05-15
We demonstrate an optical-fiber-based source of polarization-entangled photon pairs with improved quality and efficiency, which has been integrated with off-the-shelf telecom components and is, therefore, well suited for quantum communication applications in the 1550-nm telecom band. Polarization entanglement is produced by simultaneously pumping a loop of standard dispersion-shifted fiber with two orthogonally polarized pump pulses, one propagating in the clockwise and the other in the counterclockwise direction. We characterize this source by investigating two-photon interference between the generated signal-idler photon pairs under various conditions. The experimental parameters are carefully optimized to maximize the generated photon-pair correlation and to minimize contamination of the entangled photon pairs from extraneously scattered background photons that are produced by the pump pulses for two reasons: (i) spontaneous Raman scattering causes uncorrelated photons to be emitted in the signal and idler bands and (ii) broadening of the pump-pulse spectrum due to self-phase modulation causes pump photons to leak into the signal and idler bands. We obtain two-photon interference with visibility >90% without subtracting counts caused by the background photons (only dark counts of the detectors are subtracted), when the mean photon number in the signal (idler) channel is about 0.02/pulse, while no interference is observed in direct detection of either the signal or idler photons.
High-Power Fiber Lasers Using Photonic Band Gap Materials
NASA Technical Reports Server (NTRS)
DiDomenico, Leo; Dowling, Jonathan
2005-01-01
High-power fiber lasers (HPFLs) would be made from photonic band gap (PBG) materials, according to the proposal. Such lasers would be scalable in the sense that a large number of fiber lasers could be arranged in an array or bundle and then operated in phase-locked condition to generate a superposition and highly directed high-power laser beam. It has been estimated that an average power level as high as 1,000 W per fiber could be achieved in such an array. Examples of potential applications for the proposed single-fiber lasers include welding and laser surgery. Additionally, the bundled fibers have applications in beaming power through free space for autonomous vehicles, laser weapons, free-space communications, and inducing photochemical reactions in large-scale industrial processes. The proposal has been inspired in part by recent improvements in the capabilities of single-mode fiber amplifiers and lasers to produce continuous high-power radiation. In particular, it has been found that the average output power of a single strand of a fiber laser can be increased by suitably changing the doping profile of active ions in its gain medium to optimize the spatial overlap of the electromagnetic field with the distribution of active ions. Such optimization minimizes pump power losses and increases the gain in the fiber laser system. The proposal would expand the basic concept of this type of optimization to incorporate exploitation of the properties (including, in some cases, nonlinearities) of PBG materials to obtain power levels and efficiencies higher than are now possible. Another element of the proposal is to enable pumping by concentrated sunlight. Somewhat more specifically, the proposal calls for exploitation of the properties of PBG materials to overcome a number of stubborn adverse phenomena that have impeded prior efforts to perfect HPFLs. The most relevant of those phenomena is amplified spontaneous emission (ASE), which causes saturation of gain and power
Photonic band gap of three dimensional magnetized photonic crystal with Voigt configuration
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Kong, Xiang-Kun; Li, Bing-Xiang
2013-08-01
In this paper, the properties of two types of three-dimensional magnetized plasma photonic crystals (MPPCs) composed of homogeneous magnetized plasma and dielectric with simple-cubic lattices are theoretically studied by a modified plane wave expansion (PWE) method, as the magneto-optical Voigt effects of magnetized plasma are considered. The equations for type-1 structures with simple-cubic lattices (dielectric spheres immersed in magnetized plasma background), are theoretically deduced. The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, the external magnetic field and plasma frequency on the properties of photonic band gaps (PBGs) for both types of MPPCs are investigated in detail, respectively, and some corresponding physical explanations are also given. The characteristics of flatbands regions are also discussed. From the numerical results, it has been shown that the PBGs of both types of three-dimensional MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field and the relative dielectric constant of dielectric, respectively. However, the plasma collision frequency has no effects on the PBGs for two types of three-dimensional MPPCs. The locations of flatbands regions can not be tuned by any parameters except for plasma frequency and the external magnetic field.
X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment
Marsh, Roark A.; Shapiro, Michael A.; Temkin, Richard J.; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC
2012-06-11
In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.
Fabrication of 3-D Photonic Band Gap Crystals Via Colloidal Self-Assembly
NASA Technical Reports Server (NTRS)
Subramaniam, Girija; Blank, Shannon
2005-01-01
The behavior of photons in a Photonic Crystals, PCs, is like that of electrons in a semiconductor in that, it prohibits light propagation over a band of frequencies, called Photonic Band Gap, PBG. Photons cannot exist in these band gaps like the forbidden bands of electrons. Thus, PCs lend themselves as potential candidates for devices based on the gap phenomenon. The popular research on PCs stem from their ability to confine light with minimal losses. Large scale 3-D PCs with a PBG in the visible or near infra red region will make optical transistors and sharp bent optical fibers. Efforts are directed to use PCs for information processing and it is not long before we can have optical integrated circuits in the place of electronic ones.
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Li, Bing-Xiang
2016-01-01
The properties of omnidirectional photonic band gaps (OBGs) in two-dimensional plasma photonic crystals (2D PPCs) are theoretically investigated by the modified plane wave expansion method. In the simulation, we consider the off-plane incident wave vector. The configuration of 2D PPCs is the triangular lattices filled with the nonmagnetized plasma cylinders in the homogeneous and isotropic dielectric background. The calculated results show that the proposed 2D PPCs possess a flatbands region and the OBGs. Compared with the OBGs in the conventional 2D dielectric-air PCs, it can be obtained more easily and enlarged in the 2D PPCs with a similar structure. The effects of configurational parameters of the PPCs on the OBGs also are studied. The simulated results demonstrate that the locations of OBGs can be tuned easily by manipulating those parameters except for changing plasma collision frequency. The achieved OBGs can be enlarged by optimizations. The OBGs of two novel configurations of PPCs with different cross sections are computed for a comparison. Both configurations have the advantages of obtaining the larger OBGs compared with the conventional configuration, since the symmetry of 2D PPCs is broken by different sizes of periodically inserted plasma cylinders or connected by the embedded plasma cylinders with thin veins. The analysis of the results shows that the bandwidths of OBGs can be tuned by changing geometric and physical parameters of such two PPCs structures. The theoretical results may open a new scope for designing the omnidirectional reflectors or mirrors based on the 2D PPCs.
Field demonstration of X-band photonic antenna remoting in the Deep Space Network
NASA Technical Reports Server (NTRS)
Yao, X. S.; Lutes, G.; Logan, R. T., Jr.; Maleki, L.
1994-01-01
We designed a photonic link for antenna remoting based on our integrated system analysis. With this 12-km link, we successfully demonstrated photonic antenna-remoting capability at X-band (8.4 GHz) at one of NASA's Deep Space Stations while tracking the Magellan spacecraft.
NASA Astrophysics Data System (ADS)
Wang, Qiang; Xiao, Meng; Liu, Hui; Zhu, Shining; Chan, C. T.
2016-01-01
The Zak phase labels the topological property of one-dimensional Bloch bands. Here we propose a scheme and experimentally measure the Zak phase in a photonic system. The Zak phase of a bulk band is related to the topological properties of the two band gaps sandwiching this band, which in turn can be inferred from the existence or absence of an interface state. Using a reflection spectrum measurement, we determined the existence of interface states in the gaps and then obtained the Zak phases. The knowledge of Zak phases can also help us predict the existence of interface states between a metasurface and a photonic crystal. By manipulating the property of the metasurface, we can further tune the excitation frequency and the polarization of the interface state.
High-frequency homogenization of zero-frequency stop band photonic and phononic crystals
NASA Astrophysics Data System (ADS)
Antonakakis, T.; Craster, R. V.; Guenneau, S.
2013-10-01
We present an accurate methodology for representing the physics of waves, in periodic structures, through effective properties for a replacement bulk medium: this is valid even for media with zero-frequency stop bands and where high-frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low-frequency (or quasi-static) behaviour has been neatly encapsulated in effective anisotropic media; the various parameters come from asymptotic analysis relying upon the ratio of the array pitch to the wavelength being sufficiently small. However, such classical homogenization theories break down in the high-frequency or stop band regime whereby the wavelength to pitch ratio is of order one. Furthermore, arrays of inclusions with Dirichlet data lead to a zero-frequency stop band, with the salient consequence that classical homogenization is invalid. Higher-frequency phenomena are of significant importance in photonics (transverse magnetic waves propagating in infinite conducting parallel fibres), phononics (anti-plane shear waves propagating in isotropic elastic materials with inclusions) and platonics (flexural waves propagating in thin-elastic plates with holes). Fortunately, the recently proposed high-frequency homogenization (HFH) theory is only constrained by the knowledge of standing waves in order to asymptotically reconstruct dispersion curves and associated Floquet-Bloch eigenfields: it is capable of accurately representing zero-frequency stop band structures. The homogenized equations are partial differential equations with a dispersive anisotropic homogenized tensor that characterizes the effective medium. We apply HFH to metamaterials, exploiting the subtle features of Bloch dispersion curves such as Dirac-like cones, as well as zero and negative group velocity near stop bands in order to achieve exciting physical phenomena such as cloaking, lensing and endoscope effects. These are simulated numerically using finite elements and compared to predictions
Generation of narrow-band hyperentangled nondegenerate paired photons.
Yan, Hui; Zhang, Shanchao; Chen, J F; Loy, M M T; Wong, G K L; Du, Shengwang
2011-01-21
We report the generation of nondegenerate narrow-bandwidth paired photons with time-frequency and polarization entanglements from laser cooled atoms. We observe the two-photon interference caused by Rabi splitting with a coherence time of about 30 ns and a visibility of 81.8% which verifies the time-frequency entanglement of the paired photons. The polarization entanglement is confirmed by polarization correlation measurements which exhibit a visibility of 89.5% and characterized by quantum-state tomography with a fidelity of 90.8%. Taking into account the transmission losses and duty cycle, we estimate that the system generates hyperentangled paired photons into opposing single-mode fibers at a rate of 320 pairs per second. PMID:21405274
Generation of Narrow-Band Hyperentangled Nondegenerate Paired Photons
NASA Astrophysics Data System (ADS)
Yan, Hui; Zhang, Shanchao; Chen, J. F.; Loy, M. M. T.; Wong, G. K. L.; Du, Shengwang
2011-01-01
We report the generation of nondegenerate narrow-bandwidth paired photons with time-frequency and polarization entanglements from laser cooled atoms. We observe the two-photon interference caused by Rabi splitting with a coherence time of about 30 ns and a visibility of 81.8% which verifies the time-frequency entanglement of the paired photons. The polarization entanglement is confirmed by polarization correlation measurements which exhibit a visibility of 89.5% and characterized by quantum-state tomography with a fidelity of 90.8%. Taking into account the transmission losses and duty cycle, we estimate that the system generates hyperentangled paired photons into opposing single-mode fibers at a rate of 320 pairs per second.
A complete characterization of the heralded noiseless amplification of photons
NASA Astrophysics Data System (ADS)
Bruno, N.; Pini, V.; Martin, A.; Thew, R. T.
2013-09-01
Heralded noiseless amplification of photons has recently been shown to provide a means to overcome losses in complex quantum communication tasks. In particular, to overcome transmission losses that could allow for the violation of a Bell inequality free from the detection loophole, for device independent quantum key distribution (DI-QKD). Several implementations of a heralded photon amplifier have been proposed and the first proof of principle experiments realized. Here we present the first full characterization of such a device to test its functional limits and potential for DI-QKD. This device is tested at telecom wavelengths and is shown to be capable of overcoming losses corresponding to a transmission through 20 km of single mode telecom fibre. We demonstrate heralded photon amplifier with a gain >100 and a heralding probability >83%, required by DI-QKD protocols that use the Clauser-Horne-Shimony-Holt inequality. The heralded photon amplifier clearly represents a key technology for the realization of DI-QKD in the real world and over typical network distances.
Metallic photonic-band-gap filament architectures for optimized incandescent lighting
NASA Astrophysics Data System (ADS)
John, Sajeev; Wang, Rongzhou
2008-10-01
We identify an optimized three-dimensional metallic photonic-band-gap filament architecture for electrically pumped, quasithermal, visible light emission. This identification is based on extensive band structure and finite-difference time-domain calculations of metallic photonic crystals. The optimum structure consists of an inverse square-spiral photonic crystal, exhibiting a large bandwidth optical passband below the effective plasma screening frequency of the periodically structured metal. Light emission from the interior surfaces of the filament to the interior air channels occurs exclusively into the passband modes, enabling high-efficiency conversion of electrical energy into visible light.
Photocurrent induced by two-photon excitation in ZnTeO intermediate band solar cells
NASA Astrophysics Data System (ADS)
Tanaka, Tooru; Miyabara, Masaki; Nagao, Yasuhiro; Saito, Katsuhiko; Guo, Qixin; Nishio, Mitsuhiro; Yu, Kin M.; Walukiewicz, Wladek
2013-02-01
Intermediate band (IB) solar cell structures based on ZnTeO highly mismatched alloy were examined to demonstrate a photocurrent induced by a two-photon excitation (TPE) process. Two types of the devices, with and without a blocking layer for the IB, are prepared. The device with a blocked IB exhibits small external quantum efficiency (EQE) in photon energy range in which electron transitions from valence band (VB) to IB take place, implying the electron accumulation in IB. The enhancement of EQE is observed in TPE experiments as a result of electron transition from VB to conduction band via IB.
Analysis of plasma-magnetic photonic crystal with a tunable band gap
Mehdian, H.; Mohammadzahery, Z.; Hasanbeigi, A.
2013-04-15
In this paper, electromagnetic wave propagation through the one-dimensional plasma-magnetic photonic crystal in the presence of external magnetic field has been analyzed. The dispersion relation, transmission and reflection coefficients have been obtained by using the transfer matrix method. It is investigated how photonic band gap of photonic crystals will be tuned when both dielectric function {epsilon} and magnetic permeability {mu} of the constitutive materials, depend on applied magnetic field. This is shown by one dimensional photonic crystals consisting of plasma and ferrite material layers stacked alternately.
Photonic Band Gap Structures as a Gateway to Nano-Photonics
FRITZ, IAN J.; GOURLEY, PAUL L.; HAMMONS, G.; HIETALA, VINCENT M.; JONES, ERIC D.; KLEM, JOHN F.; KURTZ, SHARON L.; LIN, SHAWN-YU; LYO, SUNGKWUN K.; VAWTER, GREGORY A.; WENDT, JOEL R.
1999-08-01
This LDRD project explored the fundamental physics of a new class of photonic materials, photonic bandgap structures (PBG), and examine its unique properties for the design and implementation of photonic devices on a nano-meter length scale for the control and confinement of light. The low loss, highly reflective and quantum interference nature of a PBG material makes it one of the most promising candidates for realizing an extremely high-Q resonant cavity, >10,000, for optoelectronic applications and for the exploration of novel photonic physics, such as photonic localization, tunneling and modification of spontaneous emission rate. Moreover, the photonic bandgap concept affords us with a new opportunity to design and tailor photonic properties in very much the same way we manipulate, or bandgap engineer, electronic properties through modern epitaxy.
NASA Astrophysics Data System (ADS)
Priya Rose, T.; Di Gennaro, E.; Andreone, A.; Abbate, G.
2010-05-01
Photonic quasicrystals (PQCs) have neither true periodicity nor translational symmetry, however they can exhibit symmetries that are not achievable by conventional periodic structures. The arbitrarily high rotational symmetry of these materials can be practically exploited to manufacture isotropic band gap materials, which are perfectly suitable for hosting waveguides or cavities. In this work, formation and development of the photonic bandgap (PBG) in twodimensional 8-, 10- and 12-fold symmetry quasicrystalline lattices of low dielectric contrast (0.4-0.6) were measured in the microwave region and compared with the PBG properties of a conventional hexagonal crystal. Band-gap properties were also investigated by changing the direction of propagation of the incident beam inside the crystal. Various angles of incidence from 0° to 30° were used in order to investigate the isotropic nature of the band-gap.
Two-photon photoemission from a copper cathode in an X -band photoinjector
NASA Astrophysics Data System (ADS)
Li, H.; Limborg-Deprey, C.; Adolphsen, C.; McCormick, D.; Dunning, M.; Jobe, K.; Raubenheimer, T.; Vrielink, A.; Vecchione, T.; Wang, F.; Weathersby, S.
2016-02-01
This paper presents two-photon photoemission from a copper cathode in an X -band photoinjector. We experimentally verified that the electron bunch charge from photoemission out of a copper cathode scales with laser intensity (I) square for 400 nm wavelength photons. We compare this two-photon photoemission process with the single photon process at 266 nm. Despite the high reflectivity (R ) of the copper surface for 400 nm photons (R =0.48 ) and higher thermal energy of photoelectrons (two-photon at 200 nm) compared to 266 nm photoelectrons, the quantum efficiency of the two-photon photoemission process (400 nm) exceeds the single-photon process (266 nm) when the incident laser intensity is above 300 GW /cm2 . At the same laser pulse energy (E ) and other experimental conditions, emitted charge scales inversely with the laser pulse duration. A thermal emittance of 2.7 mm-mrad per mm root mean square (rms) was measured on our cathode which exceeds by sixty percent larger compared to the theoretical predictions, but this discrepancy is similar to previous experimental thermal emittance on copper cathodes with 266 nm photons. The damage of the cathode surface of our first-generation X -band gun from both rf breakdowns and laser impacts mostly explains this result. Using a 400 nm laser can substantially simplify the photoinjector system, and make it an alternative solution for compact pulsed electron sources.
Blanco; Chomski; Grabtchak; Ibisate; John; Leonard; Lopez; Meseguer; Miguez; Mondia; Ozin; Toader; van Driel HM
2000-05-25
Photonic technology, using light instead of electrons as the information carrier, is increasingly replacing electronics in communication and information management systems. Microscopic light manipulation, for this purpose, is achievable through photonic bandgap materials, a special class of photonic crystals in which three-dimensional, periodic dielectric constant variations controllably prohibit electromagnetic propagation throughout a specified frequency band. This can result in the localization of photons, thus providing a mechanism for controlling and inhibiting spontaneous light emission that can be exploited for photonic device fabrication. In fact, carefully engineered line defects could act as waveguides connecting photonic devices in all-optical microchips, and infiltration of the photonic material with suitable liquid crystals might produce photonic bandgap structures (and hence light-flow patterns) fully tunable by an externally applied voltage. However, the realization of this technology requires a strategy for the efficient synthesis of high-quality, large-scale photonic crystals with photonic bandgaps at micrometre and sub-micrometre wavelengths, and with rationally designed line and point defects for optical circuitry. Here we describe single crystals of silicon inverse opal with a complete three-dimensional photonic bandgap centred on 1.46 microm, produced by growing silicon inside the voids of an opal template of dose-packed silica spheres that are connected by small 'necks' formed during sintering, followed by removal of the silica template. The synthesis method is simple and inexpensive, yielding photonic crystals of pure silicon that are easily integrated with existing silicon-based microelectronics. PMID:10839534
NASA Astrophysics Data System (ADS)
Xu, Lin; Wang, Hai-Xiao; Xu, Ya-Dong; Chen, Huan-Yang; Jiang, Jian-Hua
2016-08-01
A simple core-shell two-dimensional photonic crystal is studied where the triangle lattice symmetry and $C_{6v}$ rotation symmetry leads to rich physics in the study of accidental degeneracy's in photonic bands. We systematically evaluate different types of accidental nodal points, depending on the dispersions around them and their topological properties, when the geometry and permittivity are continuously changed. These accidental nodal points can be the critical states lying between a topological phase and a normal phase and are thus important for the study of topological photonic states. In time-reversal systems, this leads to the photonic quantum spin Hall insulator where the spin is defined upon the orbital angular momentum for transverse-magnetic polarization. We study the topological phase transition as well as the properties of the edge and bulk states and their application potentials in optics.
Photonic-band-gap effects in two-dimensional polycrystalline and amorphous structures
Yang, Jin-Kyu; Noh, Heeso; Liew, Seng-Fatt; Schreck, Carl; Guy, Mikhael I.; O'Hern, Corey S.; Cao, Hui
2010-11-15
We study numerically the density of optical states (DOS) in two-dimensional photonic structures with short-range positional order and observe a transition from polycrystalline to amorphous photonic systems. In polycrystals, photonic band gaps (PBGs) are formed within individual domains, which leads to a depletion of the DOS similar to that in periodic structures. In amorphous photonic media, the domain sizes are too small to form PBGs, thus the depletion of the DOS is weakened significantly. The critical domain size that separates the polycrystalline and amorphous regimes is determined by the attenuation length of Bragg scattering, which depends not only on the degree of positional order but also the refractive-index contrast of the photonic material. Even with relatively low-refractive-index contrast, we find that modest short-range positional order in photonic structures enhances light confinement via collective scattering and interference.
Jena, S. Tokas, R. B.; Sarkar, P.; Thakur, S.; Sahoo, N. K.; Haque, S. Maidul; Misal, J. S.; Rao, K. D.
2015-06-24
The multilayer structure of TiO{sub 2}/SiO{sub 2} (11 layers) as one dimensional photonic crystal (1D PC) has been designed and then fabricated by using asymmetric bipolar pulse DC magnetron sputtering technique for omnidirectional photonic band gap. The experimentally measured photonic band gap (PBG) in the visible region is well matched with the theoretically calculated band structure (ω vs. k) diagram. The experimentally measured omnidirectional reflection band of 44 nm over the incident angle range of 0°-70° is found almost matching within the theoretically calculated band.
Tuning of full band gap in anisotropic photonic crystal slabs using a liquid crystal
NASA Astrophysics Data System (ADS)
Khalkhali, T. Fathollahi; Rezaei, B.; Ramezani, A. H.
2012-11-01
We analyze the tunability of full band gap in photonic crystal slabs created by square and triangular lattices of air holes in anisotropic tellurium background, considering that the regions above and below the slab are occupied by SiO2 and the holes are infiltrated with liquid crystals. Using the supercell method based on plane wave expansion, we study the variation of full band gap by changing the optical axis orientation of liquid crystal. Our results demonstrate the existence and remarkable tunability of full band gap in both square and triangular lattices, largest band gap and tunability being obtained for the triangular lattice.
NASA Astrophysics Data System (ADS)
Zhou, Guangyong; Gu, Min
2007-05-01
By using the femtosecond laser induced microexplosion method, high-quality two-dimensional eightfold photonic quasicrystals have been fabricated in a solid transparent polymer material. Multiorder band gaps have been observed in a 25-layer structure with a suppression rate of up to 72% for the fundamental gap. Polarization measurements show that the photonic quasicrystal has a strong anisotropic effect, showing that the transverse electric is the favorite polarization. Fabry-Pérot cavities have been fabricated by removing the central layer of channels. Based on the cavity mode position, the order of the mode and the effective cavity size have been determined.
Energy transfer from Rhodamine-B to Oxazine-170 in the presence of photonic stop band
NASA Astrophysics Data System (ADS)
Kedia, Sunita; Sinha, Sucharita
2015-03-01
Photonic crystals can effectively suppress spontaneous emission of embedded emitter in the direction were photonic stop band overlaps emission band of emitter. This property of PhC has been successfully exploited to enhance energy transfer from a donor Rhodamine-B dye to an acceptor Oxazine-170 dye by inhibiting the fluorescence emission of donor in a controlled manner. Self-assembled PhC were synthesized using RhB dye doped polystyrene microspheres subsequently infiltrated with O-170 dye molecules dissolved in ethanol. An angle dependent enhancement of emission intensity of acceptor via energy transfer in photonic crystal environment was observed. These results were compared with observations made on a dye mixture solution of the same two dyes. Restricted number of available modes in photonic crystal inhibited de-excitation of donor thereby enabling efficient transfer of energy from excited donor to acceptor dye molecules.
Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals
Henry Hao-Chuan Kang
2004-12-19
Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.
Experimental Work With Photonic Band Gap Fiber: Building A Laser Electron Accelerator
Lincoln, Melissa; Ischebeck, Rasmus; Nobel, Robert; Siemann, Robert; /SLAC
2006-09-29
In the laser acceleration project E-163 at the Stanford Linear Accelerator Center, work is being done toward building a traveling wave accelerator that uses as its accelerating structure a length of photonic band gap fiber. The small scale of the optical fiber allows radiation at optical wavelengths to be used to provide the necessary accelerating energy. Optical wavelength driving energy in a small structure yields higher accelerating fields. The existence of a speed-of-light accelerating mode in a photonic band gap fiber has been calculated previously [1]. This paper presents an overview of several of the experimental challenges posed in the development of the proposed photonic band gap fiber accelerator system.
Gupta, Sandhya; Tuttle, Gary L.; Sigalas, Mihail; McCalmont, Jonathan S.; Ho, Kai-Ming
2001-08-14
A method of manufacturing a flexible metallic photonic band gap structure operable in the infrared region, comprises the steps of spinning on a first layer of dielectric on a GaAs substrate, imidizing this first layer of dielectric, forming a first metal pattern on this first layer of dielectric, spinning on and imidizing a second layer of dielectric, and then removing the GaAs substrate. This method results in a flexible metallic photonic band gap structure operable with various filter characteristics in the infrared region. This method may be used to construct multi-layer flexible metallic photonic band gap structures. Metal grid defects and dielectric separation layer thicknesses are adjusted to control filter parameters.
Band structure of germanium carbides for direct bandgap silicon photonics
NASA Astrophysics Data System (ADS)
Stephenson, C. A.; O'Brien, W. A.; Penninger, M. W.; Schneider, W. F.; Gillett-Kunnath, M.; Zajicek, J.; Yu, K. M.; Kudrawiec, R.; Stillwell, R. A.; Wistey, M. A.
2016-08-01
Compact optical interconnects require efficient lasers and modulators compatible with silicon. Ab initio modeling of Ge1-xCx (x = 0.78%) using density functional theory with HSE06 hybrid functionals predicts a splitting of the conduction band at Γ and a strongly direct bandgap, consistent with band anticrossing. Photoreflectance of Ge0.998C0.002 shows a bandgap reduction supporting these results. Growth of Ge0.998C0.002 using tetrakis(germyl)methane as the C source shows no signs of C-C bonds, C clusters, or extended defects, suggesting highly substitutional incorporation of C. Optical gain and modulation are predicted to rival III-V materials due to a larger electron population in the direct valley, reduced intervalley scattering, suppressed Auger recombination, and increased overlap integral for a stronger fundamental optical transition.
Zero-coupling-gap degenerate band edge resonators in silicon photonics.
Burr, Justin R; Reano, Ronald M
2015-11-30
Resonances near regular photonic band edges are limited by quality factors that scale only to the third power of the number of periods. In contrast, resonances near degenerate photonic band edges can scale to the fifth power of the number periods, yielding a route to significant device miniaturization. For applications in silicon integrated photonics, we present the design and analysis of zero-coupling-gap degenerate band edge resonators. Complex band diagrams are computed for the unit cell with periodic boundary conditions that convey characteristics of propagating and evanescent modes. Dispersion features of the band diagram are used to describe changes in resonance scaling in finite length resonators. Resonators with non-zero and zero coupling gap are compared. Analysis of quality factor and resonance frequency indicates significant reduction in the number of periods required to observe fifth power scaling when degenerate band edge resonators are realized with zero-coupling-gap. High transmission is achieved by optimizing the waveguide feed to the resonator. Compact band edge cavities with large optical field distribution are envisioned for light emitters, switches, and sensors. PMID:26698725
Xu, Lin; Wang, Hai-Xiao; Xu, Ya-Dong; Chen, Huan-Yang; Jiang, Jian-Hua
2016-08-01
A simple core-shell two-dimensional photonic crystal is studied where the triangular lattice symmetry and the C_{6} point group symmetry give rich physics in accidental touching points of photonic bands. We systematically evaluate different types of accidental nodal points at the Brillouin zone center for transverse-magnetic harmonic modes when the geometry and permittivity of the core-shell material are continuously tuned. The accidental nodal points can have different dispersions and topological properties (i.e., Berry phases). These accidental nodal points can be the critical states lying between a topological phase and a normal phase of the photonic crystal. They are thus very important for the study of topological photonic states. We show that, without breaking time-reversal symmetry, by tuning the geometry of the core-shell material, a phase transition into the photonic quantum spin Hall insulator can be achieved. Here the "spin" is defined as the orbital angular momentum of a photon. We study the topological phase transition as well as the properties of the edge and bulk states and their application potentials in optics. PMID:27505772
Threshold for formation of atom-photon bound states in a coherent photonic band-gap reservoir
NASA Astrophysics Data System (ADS)
Wu, Yunan; Wang, Jing; Zhang, Hanzhuang
2016-05-01
We study the threshold for the formation of atom-photon bound (APB) states from a two-level atom embedded in a coherent photonic band-gap (PBG) reservoir. It is shown that the embedded position of the atom plays an important role in the threshold. By varying the atomic embedded position, a part of formation range of APB states can be moved from inside to outside the band gap. The direct link between the steady-state entanglement and APB states is also investigated. We show that the values of entanglement between reservoir modes reflect the amount of bounded energy caused by APB states. The feasible experimental systems for verifying the above phenomena are discussed. Our results provide a clear clue on how to form and control APB states in PBG materials.
Zhang Haifeng; Liu Shaobin; Kong Xiangkun; Bian Borui; Dai Yi
2012-11-15
In this paper, an omnidirectional photonic band gap realized by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure, which is composed of homogeneous unmagnetized plasma and two kinds of isotropic dielectric, is theoretically studied by the transfer matrix method. It has been shown that such an omnidirectional photonic band gap originates from Bragg gap in contrast to zero-n gap or single negative (negative permittivity or negative permeability) gap, and it is insensitive to the incidence angle and the polarization of electromagnetic wave. From the numerical results, the frequency range and central frequency of omnidirectional photonic band gap can be tuned by the thickness and density of the plasma but cease to change with increasing Fibonacci order. The bandwidth of omnidirectional photonic band gap can be notably enlarged. Moreover, the plasma collision frequency has no effect on the bandwidth of omnidirectional photonic band gap. It is shown that such new structure Fibonacci quasiperiodic one-dimensional ternary plasma photonic crystals have a superior feature in the enhancement of frequency range of omnidirectional photonic band gap compared with the conventional ternary and conventional Fibonacci quasiperiodic ternary plasma photonic crystals.
Research on Shore-Ship Photonic Link Performance for Two- Frequency-Band Signals
NASA Astrophysics Data System (ADS)
Zuo, Yanqin; Cong, Bo
2016-02-01
Ka and Ku bands links for shore-ship communications suffer limited bandwidth and high loss. In this paper, photonics-based links are proposed and modeled. The principle of phase modulation (PM) is elaborated and analyzed. It is showed that PM can effectively suppress high-order inter-modulation distortion (IMD), reduce the insert loss and improve the reliability of the system.
Band gap of two-dimensional fiber-air photonic crystals
NASA Astrophysics Data System (ADS)
Yang, Shu; Li, Masha
2016-04-01
A two-dimensional photonic crystal (PC) composed of textile fiber and air is initially discussed in this paper. Textile materials are so called soft materials, which are different from the previous PCs composed of rigid materials. The plain wave expansion method is used to calculate band structure of different PCs by altering component properties or structural parameters. Results show that the dielectric constant of textile fibers, fiber filling ratio and lattice arrangement are effective factors which influence PCs' band gap. Yet lattice constant and fiber diameter make inconspicuous influence on the band gap feature.
Planar Defect Modes Excited at the Band Edge of Three-dimensional Photonic Crystals
NASA Astrophysics Data System (ADS)
Iida, Masaru; Tani, Masahiko; Sakai, Kiyomi; Watanabe, Masayoshi; Kitahara, Hideaki; Tohme, Takuya; Wada Takeda, Mitsuo
2004-09-01
We experimentally and numerically studied planar defect modes excited at band-edge resonant mode frequencies in three-dimensional photonic crystals. We identified the observed peaks as the defect modes using the spectrum calculated at the defect layer. The spectrum also clarifies the difference between these modes and ordinary band-edge resonant modes. The calculated spatial distribution of the electric field in the defect modes shows that the defect modes have a characteristic field concentration in the band-edge resonant mode.
Air and dielectric bands photonic crystal microringresonator for refractive index sensing.
Urbonas, Darius; Balčytis, Armandas; Vaškevičius, Konstantinas; Gabalis, Martynas; Petruškevičius, Raimondas
2016-08-01
We present the experimental and numerical analysis of a microring resonator with an integrated one-dimensional photonic crystal fabricated on a silicon-on-insulator platform and show its applicability in bulk refractive index sensing. The photonic crystal is formed by periodically patterned, partially etched cylindrical perforations, whose induced photonic bandgap is narrower than the range of measurable wavelengths (1520-1620 nm). Of particular interest is that the microring operates in both air and dielectric bands, and the sensitivities of the resonances on both edges of the bandgap were investigated. We showed that a higher field localization inside the volume of the perforations for the air band mode leads to an increase in sensitivity. PMID:27472642
Light reflector, amplifier, and splitter based on gain-assisted photonic band gaps
NASA Astrophysics Data System (ADS)
Zhang, Yan; Liu, Yi-Mou; Zheng, Tai-Yu; Wu, Jin-Hui
2016-07-01
We study both the steady and the dynamic optical response of cold atoms trapped in an optical lattice and driven to the three-level Λ configuration. These atoms are found to exhibit gain without population inversion when an incoherent pump is applied to activate spontaneously generated coherence. Gain-assisted double photonic band gaps characterized by reflectivities over 100% then grow up near the probe resonance due to the periodic distribution of the atomic density. These band gaps along with the neighboring allowed bands of transmissivities over 100% can be tuned by modulating the control field in amplitude, frequency, and, especially, phase. Consequently it is viable to realize a reflector, an amplifier, or a splitter when a weak incident light pulse is totally reflected in the photonic band gaps, totally transmitted in the allowed bands, or equally reflected and transmitted in the intersecting regions. Our results have potential applications in all-optical networks with respect to fabricating dynamically switchable devices for manipulating photon flows at low-light levels.
The Development of Layered Photonic Band Gap Structures Using a Micro-Transfer Molding Technique
Kevin Jerome Sutherland
2001-05-01
Photonic band gap (PBG) crystals are periodic dielectric structures that manipulate electromagnetic radiation in a manner similar to semiconductor devices manipulating electrons. Whereas a semiconductor material exhibits an electronic band gap in which electrons cannot exist, similarly, a photonic crystal containing a photonic band gap does not allow the propagation of specific frequencies of electromagnetic radiation. This phenomenon results from the destructive Bragg diffraction interference that a wave propagating at a specific frequency will experience because of the periodic change in dielectric permitivity. This gives rise to a variety of optical applications for improving the efficiency and effectiveness of opto-electronic devices. These applications are reviewed later. Several methods are currently used to fabricate photonic crystals, which are also discussed in detail. This research involves a layer-by-layer micro-transfer molding ({mu}TM) and stacking method to create three-dimensional FCC structures of epoxy or titania. The structures, once reduced significantly in size can be infiltrated with an organic gain media and stacked on a semiconductor to improve the efficiency of an electronically pumped light-emitting diode. Photonic band gap structures have been proven to effectively create a band gap for certain frequencies of electro-magnetic radiation in the microwave and near-infrared ranges. The objective of this research project was originally two-fold: to fabricate a three dimensional (3-D) structure of a size scaled to prohibit electromagnetic propagation within the visible wavelength range, and then to characterize that structure using laser dye emission spectra. As a master mold has not yet been developed for the micro transfer molding technique in the visible range, the research was limited to scaling down the length scale as much as possible with the current available technology and characterizing these structures with other methods.
Ground-based Photon Path Measurements from Solar Absorption Spectra of the O2 A-band
NASA Technical Reports Server (NTRS)
Yang, Z.; Wennberg, P. O.; Cageao, R. P.; Pongetti, T. J.; Toon, G. C.; Sander, S. P.
2005-01-01
High-resolution solar absorption spectra obtained from Table Mountain Facility (TMF, 34.38degN, 117.68degW, 2286 m elevation) have been analyzed in the region of the O2 A-band. The photon paths of direct sunlight in clear sky cases are retrieved from the O2 absorption lines and compared with ray-tracing calculations based on the solar zenith angle and surface pressure. At a given zenith angle, the ratios of retrieved to geometrically derived photon paths are highly precise (approx.0.2%), but they vary as the zenith angle changes. This is because current models of the spectral lineshape in this band do not properly account for the significant absorption that exists far from the centers of saturated lines. For example, use of a Voigt function with Lorentzian far wings results in an error in the retrieved photon path of as much as 5%, highly correlated with solar zenith angle. Adopting a super-Lorentz function reduces, but does not completely eliminate this problem. New lab measurements of the lineshape are required to make further progress.
A photonic crystal waveguide with silicon on insulator in the near-infrared band
NASA Astrophysics Data System (ADS)
Tang, Hai-Xia; Zuo, Yu-Hua; Yu, Jin-Zhong; Wang, Qi-Ming
2007-07-01
A two-dimensional (2D) photonic crystal waveguide in the Γ-K direction with triangular lattice on a silicon-on-insulator (SOI) substrate in the near-infrared band is fabricated by the combination of electron beam lithography and inductively coupled plasma etching. Its transmission characteristics are analysed from the stimulated band diagram by the effective index and the 2D plane wave expansion (PWE) methods. In the experiment, the transmission band edge in a longer wavelength of the photonic crystal waveguide is about 1590 nm, which is in good qualitative agreement with the simulated value. However, there is a disagreement between the experimental and the simulated results when the wavelength ranges from 1607 to 1630 nm, which can be considered as due to the unpolarized source used in the transmission measurement.
Modeling and Design of Two-Dimensional Guided-Wave Photonic Band-Gap Devices
NASA Astrophysics Data System (ADS)
Ciminelli, Caterina; Peluso, Francesco; Armenise, Mario N.
2005-02-01
The model of two-dimensional (2-D) guided-wave photonic band-gap structures based on the Bloch-Floquet theory is proposed for the first time for both infinite and finite length devices. The efficient computation of dispersion curves and field distribution is carried out in very short computer time. Both guided and radiated modes can be easily identified to give a physical insight, even in defective structures. The accuracy of the model has been tested through the design of a very compact narrow-band 2-D guided-wave photonic band-gap filter at 1.55 μm. The filter has a channel isolation of 22 dB, a large number of channel (>80) with a channel spacing of 50 GHz, and a very short length (24 μm).
NASA Astrophysics Data System (ADS)
Gates, B.; Lu, Y.; Li, Z. Y.; Xia, Y.
Photonic crystals with stop bands located in the visible region have been fabricated by crystallizing monodispersed spherical colloids (made of polystyrene or silica) into cubic-close-packed lattices within specially designed packing cells. These crystals were oriented with their (111) planes parallel to their solid supports, and the number of these planes could be conveniently controlled from 13 to 127 layers by varying the thickness of packing cells. In accordance, the stop-band attenuation of these crystals monotonically increased from 1 to 21 dB. Our transmission spectral measurements indicated that there exists a non-linear dependence between the stop-band attenuation and the total number of (111) planes, and this dependence could be quantitatively simulated using the dynamic light scattering model or the photonic analogy to KKR method. The colloidal crystals presented here should find use as components in fabricating optical devices that include sensors, mirrors, filters, switches and waveguides.
Hydrogen production by Tuning the Photonic Band Gap with the Electronic Band Gap of TiO2
NASA Astrophysics Data System (ADS)
Waterhouse, G. I. N.; Wahab, A. K.; Al-Oufi, M.; Jovic, V.; Anjum, D. H.; Sun-Waterhouse, D.; Llorca, J.; Idriss, H.
2013-10-01
Tuning the photonic band gap (PBG) to the electronic band gap (EBG) of Au/TiO2 catalysts resulted in considerable enhancement of the photocatalytic water splitting to hydrogen under direct sunlight. Au/TiO2 (PBG-357 nm) photocatalyst exhibited superior photocatalytic performance under both UV and sunlight compared to the Au/TiO2 (PBG-585 nm) photocatalyst and both are higher than Au/TiO2 without the 3 dimensionally ordered macro-porous structure materials. The very high photocatalytic activity is attributed to suppression of a fraction of electron-hole recombination route due to the co-incidence of the PBG with the EBG of TiO2 These materials that maintain their activity with very small amount of sacrificial agents (down to 0.5 vol.% of ethanol) are poised to find direct applications because of their high activity, low cost of the process, simplicity and stability.
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Li, Bing-Xiang
2013-10-01
In this paper, the properties of photonic band gaps (PBGs) for three-dimensional magnetized plasma photonic crystals (MPPCs) composed of anisotropic dielectric (the uniaxial material) spheres immersed in homogeneous magnetized plasma background with simple-cubic lattices are theoretically investigated by the plane wave expansion (PWE) method, as the Voigt effects of magnetized plasma are considered. The equations for calculating the anisotropic PBGs in the first irreducible Brillouin zone are theoretically deduced. The anisotropic PBGs and two flatband regions can be obtained. The effects of the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency and plasma cyclotron frequency on the characteristics of anisotropic PBGs for the three-dimensional MPPCs are studied in detail and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in simple-cubic lattices and the complete PBGs can be found compared to the conventional three-dimensional MPPCs doped by the isotropic material. The bandwidths of PBGs can be enlarged by introducing the magnetized plasma into three-dimensional PCs containing the uniaxial material. It is also shown that the anisotropic PBGs can be manipulated by the ordinary-refractive index, extraordinary-refractive index, filling factor, plasma frequency and plasma cyclotron frequency. The locations of flatband regions cannot be tuned by any parameters except for the plasma frequency and plasma cyclotron frequency. Introducing the uniaxial material in three-dimensional magnetized plasma-dielectric photonic crystals can enlarge the PBGs and also provide a way to obtain the complete PBGs as the three-dimensional MPPCs with high symmetry.
Theoretical aspects of photonic band gap in 1D nano structure of LN: MgLN periodic layer
Sisodia, Namita
2015-06-24
By using the transfer matrix method, we have analyzed the photonic band gap properties in a periodic layer of LN:MgLN medium. The Width of alternate layers of LN and MgLN is in the range of hundred nanometers. The birefringent and ferroelectric properties of the medium (i.e ordinary, extraordinary refractive indices and electric dipole moment) is given due considerations in the formulation of photonic band gap. Effect of electronic transition dipole moment of the medium on photonic band gap is also taken into account. We find that photonic band gap can be modified by the variation in the ratio of the width of two medium. We explain our findings by obtaining numerical values and the effect on the photonic band gap due to variation in the ratio of alternate medium is shown graphically.
Experimental and Theoretical Studies of Photonic Band gaps in Artificial Opals
NASA Astrophysics Data System (ADS)
Wang, Lei; Yin, Ming; Arammash, Fouzi; Datta, Timir
2014-03-01
Photonic band structure and band gap were numerically computed for a number of closed packed simple cubic and Hexagonal arrangements of non-conducting spheres using ``Finite Difference Time Domain Method''. Photonic gaps were found to exist in the simple cubic overlapping spheres with index of refraction (n) >3.2. Gap increased linearly from 0.117- 0.161 (1/micron) as lattice constant decreased from 0.34 to 0.18 (micron). For less than 3.2 no gap was obtained. Also, no gaps were obtained for hexagonal packing. UV-VIS reflectivity and transmission measurements of polycrystalline bulk artificial opals of silica (SiO2) spheres, ranging from 250nm to 300nm in sphere diameter indicate a reflection peak in the 500-600 nm regimes. Consistent with photonic band gap behavior we find that reflectivity is enhanced in the same wavelength where transmission is reduced. To the best of our knowledge this is the first observation of photonic gap in the visible wave length under ambient conditions. The wave length at the reflectance peak increases with the diameter of the SiO2 spheres, and is approximately twice the diameter following Bragg reflection. DOD Award No 60177-RT-H from ARO.
Silvered three-dimensional polymeric photonic crystals having a large mid-infrared stop band
NASA Astrophysics Data System (ADS)
Kuebler, Stephen M.; Tal, Amir; Chen, Yun-Sheng
2007-02-01
Interest in three-dimensional (3D) metal photonic crystals (MPCs) has grown considerably given their potential applications in optics and photonics. Yet, experimental studies of such materials remain few because of the difficulties associated with fabricating 3D micron- and sub-micron-scale metallic structures. We report a route to MPCs based on metallization of 3D polymeric photonic crystals fabricated by multi-photon direct laser writing. Polymeric photonic crystals (PCs) having simple-cubic symmetry with periodicities varying from 1.6 to 3.2 microns were created using a cross-linkable acrylate pre-polymer. The resulting dielectric PCs were metallized by electroless deposition of silver. Analysis of the metallized structures in cross-section by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy shows that silver deposited conformally onto the entire micro-porous lattice. The dielectric and metallized PCs were characterized by Fourier transform infrared (FTIR) spectroscopy in the (001) direction. The polymer photonic crystals exhibit a stop band resulting in circa 60% reflectance centered at 3.2 to 6.4 microns, depending upon the lattice period, with a full-width at half-maximum (FWHM) of 500 nm. Interestingly, FTIR spectra of the metallized PCs show widened stop bands of nearly 6 microns FWHM, while the center wavelengths were red shifted and ranged from 6 to 7 microns. The appreciable broadening of the stop band due to the presence of the deposited silver is a result consistent with previously reported theoretical and experimental data for all-metallic 3D PCs. Thus, the approach described here appears suitable for fabricating 3D MPCs of many symmetries and basis sets and provides a path for integrating such structures with other micron-scale optical elements.
Parametric analysis of 2D guided-wave photonic band gap structures
NASA Astrophysics Data System (ADS)
Ciminelli, C.; Peluso, F.; Armenise, M. N.
2005-11-01
The parametric analysis of the electromagnetic properties of 2D guided wave photonic band gap structures is reported with the aim of providing a valid tool for the optimal design. The modelling approach is based on the Bloch-Floquet method. Different lattice configurations and geometrical parameters are considered. An optimum value for the ratio between the hole (or rod) radius and the lattice constant does exist and the calculation demonstrated that it is almost independent from the etching depth, only depending on the lattice type. The results are suitable for the design optimisation of photonic crystal reflectors to be used in integrated optical devices.
Parametric analysis of 2D guided-wave photonic band gap structures.
Ciminelli, C; Peluso, F; Armenise, M
2005-11-28
The parametric analysis of the electromagnetic properties of 2D guided wave photonic band gap structures is reported with the aim of providing a valid tool for the optimal design. The modelling approach is based on the Bloch-Floquet method. Different lattice configurations and geometrical parameters are considered. An optimum value for the ratio between the hole (or rod) radius and the lattice constant does exist and the calculation demonstrated that it is almost independent from the etching depth, only depending on the lattice type. The results are suitable for the design optimisation of photonic crystal reflectors to be used in integrated optical devices. PMID:19503180
Isotropic properties of the photonic band gap in quasicrystals with low-index contrast
NASA Astrophysics Data System (ADS)
Priya Rose, T.; di Gennaro, E.; Abbate, G.; Andreone, A.
2011-09-01
We report on the formation and development of the photonic band gap in two-dimensional 8-, 10-, and 12-fold symmetry quasicrystalline lattices of low-index contrast. Finite-size structures made of dielectric cylindrical rods were studied and measured in the microwave region, and their properties were compared with a conventional hexagonal crystal. Band-gap characteristics were investigated by changing the direction of propagation of the incident beam inside the crystal. Various angles of incidence from 0∘ to 30∘ were used to investigate the isotropic nature of the band gap. The arbitrarily high rotational symmetry of aperiodically ordered structures could be practically exploited to manufacture isotropic band-gap materials, which are perfectly suitable for hosting waveguides or cavities.
Spin polarized photons from an axially charged plasma at weak coupling: Complete leading order
NASA Astrophysics Data System (ADS)
Mamo, Kiminad A.; Yee, Ho-Ung
2016-03-01
In the presence of (approximately conserved) axial charge in the QCD plasma at finite temperature, the emitted photons are spin aligned, which is a unique P - and C P -odd signature of axial charge in the photon emission observables. We compute this "P -odd photon emission rate" in a weak coupling regime at a high temperature limit to complete leading order in the QCD coupling constant: the leading log as well as the constant under the log. As in the P -even total emission rate in the literature, the computation of the P -odd emission rate at leading order consists of three parts: (1) Compton and pair annihilation processes with hard momentum exchange, (2) soft t - and u -channel contributions with hard thermal loop resummation, (3) Landau-Pomeranchuk-Migdal resummation of collinear bremsstrahlung and pair annihilation. We present analytical and numerical evaluations of these contributions to our P -odd photon emission rate observable.
Dual-band bandpass tunable microwave photonic filter based on stimulated Brillouin scattering
NASA Astrophysics Data System (ADS)
Li, Jia-qi; Xiao, Yong-chuan; Dong, Wei; Zhang, Xin-dong
2016-07-01
A dual-band bandpass microwave photonic filter (MPF) based on stimulated Brillouin scattering (SBS) is theoretically analyzed and experimentally demonstrated. Two separated tunable laser sources (TLSs) are employed to generate two passbands by implementing phase modulation to amplitude modulation conversion by using SBS induced sideband amplification. The center frequencies of both passbands can be independently tuned ranging from 1 GHz to 19 GHz. High resolution with 3 dB bandwidth less than 30 MHz and large out-of-band rejection about 40 dB under 25 mW optical pump power are achieved.
Trevisanutto, P. E.; Sushko, Petr V.; Beck, Kenneth M.; Joly, Alan G.; Hess, Wayne P.; Shluger, Alexander L.
2009-01-29
Nanoparticles of wide-band-gap materials MgO and CaO, subjected to low-intensity ultraviolet irradiation with 266 nm (4.66 eV) photons, emit hyperthermal oxygen atoms with kinetic energies up to ~ 0.4 eV. We use ab initio embedded cluster methods to study theoretically a variety of elementary photoinduced processes at both ideal and defect-containing surfaces of these nanoparticles and develop a mechanism for the desorption process. The proposed mechanism includes multiple local photoexcitations resulting in sequential formation of localized excitons, their ionization, and further excitations. It is suggested that judicious choice of sub-band-gap photon energies can be used to selectively modify surfaces of nanomaterials.
Ozbay, Ekmel; Tuttle, Gary; Michel, Erick; Ho, Kai-Ming; Biswas, Rana; Chan, Che-Ting; Soukoulis, Costas
1995-01-01
A method for fabricating a periodic dielectric structure which exhibits a photonic band gap. Alignment holes are formed in a wafer of dielectric material having a given crystal orientation. A planar layer of elongate rods is then formed in a section of the wafer. The formation of the rods includes the step of selectively removing the dielectric material of the wafer between the rods. The formation of alignment holes and layers of elongate rods and wafers is then repeated to form a plurality of patterned wafers. A stack of patterned wafers is then formed by rotating each successive wafer with respect to the next-previous wafer, and then placing the successive wafer on the stack. This stacking results in a stack of patterned wafers having a four-layer periodicity exhibiting a photonic band gap.
Photonic Generation of Dual-Band Power-Efficient Millimeter-Wave UWB Signals
NASA Astrophysics Data System (ADS)
Xiang, Peng; Guo, Hao; Chen, Dalei; Zhou, Hua
2015-05-01
Ultra-wideband (UWB) technology has attracted great interest because it can provide a promising solution of future radar and short-range broadband wireless communications. The generation of millimeter-wave UWB signals using photonic approaches can reduce the high cost of the millimeter-wave electrical circuits. Moreover, it is well compatible with fiber transmission, which can effectively extend its signal coverage. In this paper, a novel approach to the photonic generation of millimeter-wave UWB signals with dual-band operation consideration is proposed. The proposed scheme can simultaneously generate millimeter-wave UWB signals in both 24 GHz and 60 GHz millimeter band, and can efficiently exploit the spectrum limit allowed by the FCC mask by using the linear combination pulse design concept. A model describing the proposed system is developed and the generation of 24/60 GHz millimeter-wave UWB signals is demonstrated via computer simulations.
Influence of structural parameters on tunable photonic band gaps modulated by liquid crystals
NASA Astrophysics Data System (ADS)
Huang, Aiqin; Zheng, Jihong; Jiang, Yanmeng; Zhou, Zengjun; Tang, Pingyu; Zhuang, Songlin
2011-10-01
Tunable photonic crystals (PCs), which are infiltrated with nematic liquid crystals (LCs), tune photonic band gap (PBG) by rotating directors of LCs when applied with the external electrical field. Using the plane wave expansion method, we simulated the PBG structure of two-dimensional tunable PCs with a triangular lattice of circular column, square column and hexagon column, respectively. When PCs are composed of LCs and different substrate materials such as germanium (Ge) and silicon (Si), the influence of structural parameters including column shape and packing ration on PBG is discussed separately. Numerical simulations show that absolute PBG can't be found at any conditions, however large tuning range of polarized wave can be achieved by rotating directors of LCs. The simulation results provide theoretical guidance for the fabrication of field-sensitive polarizer with big tunable band range.
Ozbay, E.; Tuttle, G.; Michel, E.; Ho, K.M.; Biswas, R.; Chan, C.T.; Soukoulis, C.
1995-04-11
A method is disclosed for fabricating a periodic dielectric structure which exhibits a photonic band gap. Alignment holes are formed in a wafer of dielectric material having a given crystal orientation. A planar layer of elongate rods is then formed in a section of the wafer. The formation of the rods includes the step of selectively removing the dielectric material of the wafer between the rods. The formation of alignment holes and layers of elongate rods and wafers is then repeated to form a plurality of patterned wafers. A stack of patterned wafers is then formed by rotating each successive wafer with respect to the next-previous wafer, and then placing the successive wafer on the stack. This stacking results in a stack of patterned wafers having a four-layer periodicity exhibiting a photonic band gap. 42 figures.
Optimization of band gap of photonic crystals fabricated by holographic lithography
NASA Astrophysics Data System (ADS)
Yang, X.-L.; Cai, L.-Z.; Wang, Y.-R.; Feng, C.-S.; Dong, G.-Y.; Shen, X.-X.; Meng, X.-F.; Hu, Y.
2008-01-01
Generally the photonic band gap (PBG) is a multi-variable function of several parameters related to the shape and size of the dielectric columns of photonic crystals (PhCs), and a time-consuming step-by-step scanning process for each parameter has to be used to find their best combination yielding maximum PBG. In this letter, the widely used Nelder-Mead simplex algorithm is introduced to optimize these parameters simultaneously to find a larger PBG for a new kind of two-dimensional (2D) hexagonal GaAs-Air PhC. This structure can be conveniently produced by the single-exposure holographic lithography, and the specific holographic design is also systematically investigated. This study reveals that the band gaps of PhCs made by holographic lithography may be widened by introducing irregularity of the columns and lowering the symmetry of the structure.
UV-VIS regime band gap in a 3-d photonic system
NASA Astrophysics Data System (ADS)
Yin, Ming; Arammash, Fouzi; Datta, Timir; Tsu, Ray
2013-03-01
Synthetic opals are self-organized bulk, close packed systems that are three-dimensionally ordered with periodicity determined by the sphere diameter. These materials have been used as templates for nano devices with novel properties. For example, in carbon inverse opals show quantum hall effect and related magneto electric responses. Inverse are also reported to show photonic band gap. It is expected that devices based on these materials will be an alternative to electronic devices. These opal specimens were hexagonal or face centered cubic crystals with silica sphere diameter ranging between 220 nm and 270nm. Here we will present results of structural and imaging studies such as SEM, AFM and XRD. In addition results of the (UV-VIS) optical behavior will be provided. The optical response will be analyzed in terms of photonic band gaps in the sub-micrometer optical and UV regime.
Spatially graded TiO₂-SiO₂ Bragg reflector with rainbow-colored photonic band gap.
Singh, Dhruv Pratap; Lee, Seung Hee; Choi, Il Yong; Kim, Jong Kyu
2015-06-29
A simple single-step method to fabricate spatially graded TiO2-SiO2 Bragg stack with rainbow colored photonic band gap is presented. The gradation in thickness of the Bragg stack was accomplished with a modified glancing angle deposition (GLAD) technique with dynamic shadow enabled by a block attached to one edge of the rotating substrate. A linear gradation in thickness over a distance of about 17 mm resulted in a brilliant colorful rainbow pattern. Interestingly, the photonic band gap position can be changed across the whole visible wavelength range by linearly translating the graded Bragg stack over a large area substrate. The spatially graded Bragg stack may find potential applications in the tunable optical devices, such as optical filters, reflection gratings, and lasers. PMID:26191764
NASA Astrophysics Data System (ADS)
Graugnard, Elton; Gaillot, Davy P.; King, Jeffrey S.; Summers, Christopher J.
2006-04-01
We report the controllable and tunable fabrication of structurally modified non-close-packed inverse shell opals using multi-layer atomic layer deposition and present a model and simulation algorithm to calculate the structural parameters critical to fabrication. This powerful, flexible and unique technique enables opal inversion, structural modification and backfilling and was applied to the fabrication of TiO II non-close-packed inverse opals. Using successive conformal backfilling it was possible to tune the Bragg peak over 600 nm and enhance the Bragg peak width by >50%. Additionally, band structure calculations, using dielectric functions approximating the true network topology, were used to predict the optical properties during the fabrication process. 3D finite-difference-time-domain results predict experimentally achievable structures with a complete band gap as large as 7.2%. Additionally, the refractive index requirement was predicted to decrease from 3.3 in an 86% infiltrated inverse shell opal to 3.0 in an optimized non-close-packed inverse shell opal. It was also shown for these structures that the complete photonic band gap peak can be statically tuned by over 70% by increasing the backfilled thickness.
High brightness photonic band crystal semiconductor lasers in the passive mode locking regime
Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D.; Posilović, K.; Pohl, J.; Weyers, M.
2014-10-20
High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm{sup −2} sr{sup −1} are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.
A versatile optical junction using photonic band-gap guidance and self collimation
Gupta, Man Mohan; Medhekar, Sarang
2014-09-29
We show that it is possible to design two photonic crystal (PC) structures such that an optical beam of desired wavelength gets guided within the line defect of the first structure (photonic band gap guidance) and the same beam gets guided in the second structure by self-collimation. Using two dimensional simulation of a design made of the combination of these two structures, we propose an optical junction that allows for crossing of two optical signals of same wavelength and same polarization with very low crosstalk. Moreover, the junction can be operated at number of frequencies in a wide range. Crossing of multiple beams with very low cross talk is also possible. The proposed junction should be important in future integrated photonic circuits.
Photonic band gap in (Pb,La)(Zr,Ti)O3 inverse opals
NASA Astrophysics Data System (ADS)
Li, Bo; Zhou, Ji; Hao, Lifeng; Hu, Wei; Zong, Ruilong; Cai, Minmin; Fu, Min; Gui, Zhilun; Li, Longtu; Li, Qi
2003-05-01
(Pb,La)(Zr,Ti)O3 (PLZT) inverse opal photonic crystals were synthesized by a process of self-assembly in combination with a sol-gel technique. In this process, PLZT precursors were infiltrated into the interstices of the opal template assembled by monodisperse submicron polystyrene spheres, and then gelled in a humid environment. Polystyrene template was removed by calcining the specimen at a final temperature of 700 °C accompanied with the crystallization of perovskite phase in PLZT inverse opal network. Scanning electron microscope images show that the inverse opals possess a fcc structure with a lattice constant of 250 nm. A wide photonic band gap in the visible range is observed from transmission spectra of the sample. Such PLZT inverse opals as photonic crystals should be of importance in device applications.
All-optical dynamical Casimir effect in a three-dimensional terahertz photonic band gap
NASA Astrophysics Data System (ADS)
Hagenmüller, David
2016-06-01
We identify an architecture for the observation of all-optical dynamical Casimir effect in realistic experimental conditions. We suggest that by integrating quantum wells in a three-dimensional (3D) photonic band-gap material made out of large-scale (˜200 -μ m ) germanium logs, it is possible to achieve ultrastrong light-matter coupling at terahertz frequencies for the cyclotron transition of a two-dimensional electron gas interacting with long-lived optical modes, in which vacuum Rabi splitting is comparable to the Landau level spacing. When a short, intense electromagnetic transient of duration ˜250 fs and carrying a peak magnetic field ˜5 T is applied to the structure, the cyclotron transition can be suddenly tuned on resonance with a desired photon mode, switching on the light-matter interaction and leading to a Casimir radiation emitted parallel to the quantum well plane. The radiation spectrum consists of sharp peaks with frequencies coinciding with engineered optical modes within the 3D photonic band gap, and its characteristics are extremely robust to the nonradiative damping which can be large in our system. Furthermore, the absence of continuum with associated low-energy excitations for both electromagnetic and electronic quantum states can prevent the rapid absorption of the photon flux which is likely to occur in other proposals for all-optical dynamical Casimir effect.
Wang, Zhiguo; Ullah, Zakir; Gao, Mengqin; Zhang, Dan; Zhang, Yiqi; Gao, Hong; Zhang, Yanpeng
2015-01-01
Optical transistor is a device used to amplify and switch optical signals. Many researchers focus on replacing current computer components with optical equivalents, resulting in an optical digital computer system processing binary data. Electronic transistor is the fundamental building block of modern electronic devices. To replace electronic components with optical ones, an equivalent optical transistor is required. Here we compare the behavior of an optical transistor with the reflection from a photonic band gap structure in an electromagnetically induced transparency medium. A control signal is used to modulate the photonic band gap structure. Power variation of the control signal is used to provide an analogy between the reflection behavior caused by modulating the photonic band gap structure and the shifting of Q-point (Operation point) as well as amplification function of optical transistor. By means of the control signal, the switching function of optical transistor has also been realized. Such experimental schemes could have potential applications in making optical diode and optical transistor used in quantum information processing. PMID:26349444
NASA Astrophysics Data System (ADS)
Wang, Zhiguo; Ullah, Zakir; Gao, Mengqin; Zhang, Dan; Zhang, Yiqi; Gao, Hong; Zhang, Yanpeng
2015-09-01
Optical transistor is a device used to amplify and switch optical signals. Many researchers focus on replacing current computer components with optical equivalents, resulting in an optical digital computer system processing binary data. Electronic transistor is the fundamental building block of modern electronic devices. To replace electronic components with optical ones, an equivalent optical transistor is required. Here we compare the behavior of an optical transistor with the reflection from a photonic band gap structure in an electromagnetically induced transparency medium. A control signal is used to modulate the photonic band gap structure. Power variation of the control signal is used to provide an analogy between the reflection behavior caused by modulating the photonic band gap structure and the shifting of Q-point (Operation point) as well as amplification function of optical transistor. By means of the control signal, the switching function of optical transistor has also been realized. Such experimental schemes could have potential applications in making optical diode and optical transistor used in quantum information processing.
Precision X-Band Linac Technologies for Nuclear Photonics Gamma-Ray Sources
Hartemann, F V; Albert, F; Anderson, S G; Bayramian, A J; Cross, R R; Ebbers, C A; Gibson, D J; Houck, T L; Marsh, R A; Messerly, M J; Siders, C W; McNabb, D P; Barty, C J; Adolphsen, C E; Chu, T S; Jongewaard, E N; Tantawi, S G; Vlieks, A E; Wang, F; Wang, J W; Raubenheimer, T O; Ighigeanu, D; Toma, M; Cutoiu, D
2011-08-31
Nuclear photonics is an emerging field of research requiring new tools, including high spectral brightness, tunable gamma-ray sources; high photon energy, ultrahigh-resolution crystal spectrometers; and novel detectors. This presentation focuses on the precision linac technology required for Compton scattering gamma-ray light sources, and on the optimization of the laser and electron beam pulse format to achieve unprecedented spectral brightness. Within this context, high-gradient X-band technology will be shown to offer optimal performance in a compact package, when used in conjunction with the appropriate pulse format, and photocathode illumination and interaction laser technologies. The nascent field of nuclear photonics is enabled by the recent maturation of new technologies, including high-gradient X-band electron acceleration, robust fiber laser systems, and hyper-dispersion CPA. Recent work has been performed at LLNL to demonstrate isotope-specific detection of shielded materials via NRF using a tunable, quasi-monochromatic Compton scattering gamma-ray source operating between 0.2 MeV and 0.9 MeV photon energy. This technique is called Fluorescence Imaging in the Nuclear Domain with Energetic Radiation (or FINDER). This work has, among other things, demonstrated the detection of {sup 7}Li shielded by Pb, utilizing gamma rays generated by a linac-driven, laser-based Compton scattering gamma-ray source developed at LLNL. Within this context, a new facility is currently under construction at LLNL, with the goal of generating tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range, at a repetition rate of 120 Hz, and with a peak brightness in the 10{sup 20} photons/(s x mm{sup 2} x mrad{sup 2} x 0.1% bw).
Complete multipactor suppression in an X-band dielectric-loaded accelerating structure
NASA Astrophysics Data System (ADS)
Jing, C.; Gold, S. H.; Fischer, Richard; Gai, W.
2016-05-01
Multipactor is a major issue limiting the gradient of rf-driven Dielectric-Loaded Accelerating (DLA) structures. Theoretical models have predicted that an axial magnetic field applied to DLA structures may completely block the multipactor discharge. However, previous attempts to demonstrate this magnetic field effect in an X-band traveling-wave DLA structure were inconclusive, due to the axial variation of the applied magnetic field, and showed only partial suppression of the multipactor loading [Jing et al., Appl. Phys. Lett. 103, 213503 (2013)]. The present experiment has been performed under improved conditions with a uniform axial magnetic field extending along the length of an X-band standing-wave DLA structure. Multipactor loading began to be continuously reduced starting from 3.5 kG applied magnetic field and was completely suppressed at ˜8 kG. Dependence of multipactor suppression on the rf gradient inside the DLA structure was also measured.
Inverse dispersion method for calculation of complex photonic band diagram and PT symmetry
NASA Astrophysics Data System (ADS)
Rybin, Mikhail V.; Limonov, Mikhail F.
2016-04-01
We suggest an inverse dispersion method for calculating a photonic band diagram for materials with arbitrary frequency-dependent dielectric functions. The method is able to calculate the complex wave vector for a given frequency by solving the eigenvalue problem with a non-Hermitian operator. The analogy with PT -symmetric Hamiltonians reveals that the operator corresponds to the momentum as a physical quantity, and the singularities at the band edges are related to the branch points and responses for the features on the band edges. The method is realized using a plane wave expansion technique for a two-dimensional periodic structure in the case of TE and TM polarizations. We illustrate the applicability of the method by the calculation of the photonic band diagrams of an infinite two-dimensional square lattice composed of dielectric cylinders using the measured frequency-dependent dielectric functions of different materials (amorphous hydrogenated carbon, silicon, and chalcogenide glass). We show that the method allows one to distinguish unambiguously between Bragg and Mie gaps in the spectra.
Photonic band-gap modulation of blue phase liquid crystal (Presentation Recording)
NASA Astrophysics Data System (ADS)
Lin, Tsung-Hsien
2015-10-01
Blue phase liquid crystals (BPLCs) are self-assembled 3D photonic crystals exhibiting high susceptibility to external stimuli. Two methods for the photonic bandgap tuning of BPs were demonstrated in this work. Introducing a chiral azobenzene into a cholesteric liquid crystal could formulate a photoresponsive BPLC. Under violet irradiation, the azo dye experiences trans-cis isomerization, which leads to lattice swelling as well as phase transition in different stages of the process. Ultrawide reversible tuning of the BP photonic bandgap from ultraviolet to near infrared has been achieved. The tuning is reversible and nonvolatile. We will then demonstract the electric field-induced bandgap tuning in polymer-stabilized BPLCs. Under different BPLCs material preparation conditions, both red-shift and broadening of the photonic bandgaps have been achieved respectively. The stop band can be shifted over 100 nm. The bandwidth can be expanded from ~ 30 nm to ~ 250 nm covering nearly the full visible range. It is believed that the developed approaches could strongly promote the use of BPLC in photonic applications.
Photoswitching properties of photonic band gap materials containing azo-polymer liquid crystal
NASA Astrophysics Data System (ADS)
Moritsugu, Masaki; Shirota, Tomomi; Kubo, Shoichi; Kim, Sun-nam; Ogata, Tomonari; Nonaka, Takamasa; Sato, Osamu; Kurihara, Seiji
2008-08-01
Photochemically tunable photonic band gap materials were prepared by infiltration of liquid crystal polymers having azobenzene groups into voids of SiO2 inverse opal films. Linearly polarized light irradiation resulted in transformation from a random to an anisotropic molecular orientation of azobenzene side chains in the voids of the SiO2 inverse opal film, leading to the reversible and stable shift of the reflection band to longer wavelength more than 15 nm. In order to improve switching properties, we used copolymers with azobenzene monomer and tolane monomer, which indicate higher birefringence, as infiltration materials into the voids. The azo-tolane copolymers were found to show the higher birefringence than azobenzene homopolymers by the linearly polarized light irradiation. Thus, the reflection band of the SiO2 inverse opal film infiltrated with the azo-tolane copolymers was shifted to long wavelength region more than 55 nm by the irradiation of linearly polarized light.
Low-threshold photonic-band-edge laser using iron-nail-shaped rod array
Choi, Jae-Hyuck; No, You-Shin; Hwang, Min-Soo; Jeong, Kwang-Yong; Park, Hong-Gyu E-mail: hgpark@korea.ac.kr; Kwon, Soon-Yong; Yang, Jin-Kyu E-mail: hgpark@korea.ac.kr; Kwon, Soon-Hong
2014-03-03
We report the experimental demonstration of an optically pumped rod-type photonic-crystal band-edge laser. The structure consists of a 20 × 20 square lattice array of InGaAsP iron-nail-shaped rods. A single-mode lasing action is observed with a low threshold of ∼90 μW and a peak wavelength of 1451.5 nm at room temperature. Measurements of the polarization-resolved mode images and lasing wavelengths agree well with numerical simulations, which confirm that the observed lasing mode originates from the first Γ-point transverse-electric-like band-edge mode. We believe that this low-threshold band-edge laser will be useful for the practical implementation of nanolasers.
Zhang Haifeng; Liu Shaobin; Kong Xiangkun, Chenchen; Bian Borui
2013-04-15
In this paper, the properties of photonic band gaps (PBGs) for two types of three-dimensional plasma photonic crystals (PPCs) composed of isotropic dielectric and unmagnetized plasma with diamond lattices are theoretically investigated for electromagnetic waves based on a modified plane wave expansion method. The equations for type-1 structure are theoretically deduced, which depend on the diamond lattices realization (dielectric spheres immersed in plasma background). The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, and plasma frequency on PBGs are investigated, respectively, and some corresponding physical explanations and the possible methods to realize the three-dimensional PPCs in experiments are also given. From the numerical results, it has been shown that not only the locations but also the gap/midgap ratios of the PBGs for two types of PPCs can be tuned by plasma frequency, filling factor, and the relative dielectric constant, respectively. However, the plasma collision frequency has no effect on the frequency ranges and gap/midgap ratios of the PBGs for two types of PPCs.
Zhang HaiFeng; Liu Shaobin; Yang Huan; Kong Xiangkun
2013-03-15
In this paper, the magnetooptical effects in dispersive properties for two types of three-dimensional magnetized plasma photonic crystals (MPPCs) containing homogeneous dielectric and magnetized plasma with diamond lattices are theoretically investigated for electromagnetic (EM) wave based on plane wave expansion (PWE) method, as incidence EM wave vector is parallel to the external magnetic field. The equations for two types of MPPCs with diamond lattices (dielectric spheres immersed in magnetized plasma background or vice versa) are theoretically deduced. The influences of dielectric constant, plasma collision frequency, filling factor, the external magnetic field, and plasma frequency on the dispersive properties for both types of structures are studied in detail, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that the photonic band gaps (PBGs) for both types of MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field, and the relative dielectric constant of dielectric, respectively. Especially, the external magnetic field can enlarge the PBG for type-2 structure (plasma spheres immersed in dielectric background). However, the plasma collision frequency has no effect on the dispersive properties of two types of three-dimensional MPPCs. The locations of flatbands regions for both types of structures cannot be tuned by any parameters except for plasma frequency and the external magnetic field. The analytical results may be informative and of technical use to design the MPPCs devices.
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Kong, Xiang-Kun; Chen-Chen; Bian, Bo-Rui
2013-04-01
In this paper, the properties of photonic band gaps (PBGs) for two types of three-dimensional plasma photonic crystals (PPCs) composed of isotropic dielectric and unmagnetized plasma with diamond lattices are theoretically investigated for electromagnetic waves based on a modified plane wave expansion method. The equations for type-1 structure are theoretically deduced, which depend on the diamond lattices realization (dielectric spheres immersed in plasma background). The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, and plasma frequency on PBGs are investigated, respectively, and some corresponding physical explanations and the possible methods to realize the three-dimensional PPCs in experiments are also given. From the numerical results, it has been shown that not only the locations but also the gap/midgap ratios of the PBGs for two types of PPCs can be tuned by plasma frequency, filling factor, and the relative dielectric constant, respectively. However, the plasma collision frequency has no effect on the frequency ranges and gap/midgap ratios of the PBGs for two types of PPCs.
NASA Astrophysics Data System (ADS)
Zhukovsky, Sergei V.; Orlov, Alexey A.; Babicheva, Viktoriia E.; Lavrinenko, Andrei V.; Sipe, J. E.
2014-07-01
We study theoretically the propagation of large-wave-vector waves (volume plasmon polaritons) in multilayer hyperbolic metamaterials with two levels of structuring. We show that when the parameters of a subwavelength metal-dielectric multilayer (substructure) are modulated (superstructured) on a larger, wavelength scale, the propagation of volume plasmon polaritons in the resulting multiscale hyperbolic metamaterials is subject to photonic-band-gap phenomena. A great degree of control over such plasmons can be exerted by varying the superstructure geometry. When this geometry is periodic, stop bands due to Bragg reflection form within the volume plasmonic band. When a cavity layer is introduced in an otherwise periodic superstructure, resonance peaks of the Fabry-Pérot nature are present within the stop bands. More complicated superstructure geometries are also considered. For example, fractal Cantor-like multiscale metamaterials are found to exhibit characteristic self-similar spectral signatures in the volume plasmonic band. Multiscale hyperbolic metamaterials are shown to be a promising platform for large-wave-vector bulk plasmonic waves, whether they are considered for use as a kind of information carrier or for far-field subwavelength imaging.
Micro-metric electronic patterning of a topological band structure using a photon beam
NASA Astrophysics Data System (ADS)
Golden, Mark; Frantzeskakis, Emmanouil; de Jong, Nick; Huang, Yingkai; Wu, Dong; Pan, Yu; de Visser, Anne; van Heumen, Erik; van Bay, Tran; Zwartsenberg, Berend; Pronk, Pieter; Varier Ramankutty, Shyama; Tytarenko, Alona; Xu, Nan; Plumb, Nick; Shi, Ming; Radovic, Milan; Varkhalov, Andrei
2015-03-01
The only states crossing EF in ideal, 3D TIs are topological surface states. Single crystals of Bi2Se3andBi2Te3 are too defective to exhibit bulk-insulating behaviour, and ARPES shows topologically trivial 2DEGs at EF in the surface region due to downward band bending. Ternary & quaternary alloys of Bi /Te /Se /Sb hold promise for obtaining bulk-insulating crystals. Here we report ARPES data from quaternary, bulk-insulating, Bi-based TIs. Shortly after cleavage in UHV, downward band bending pulls the bulk conduction band below EF, once again frustrating the ``topological only'' ambition for the Fermi surface. However, there is light at the end of the tunnel: we show that a super-band-gap photon beam generates a surface photovoltage sufficient to flatten the bands, thereby recovering the ideal, ``topological only'' situation. In our bulk-insulating quaternary TIs, this effect is local in nature, and permits the writing of arbitrary, micron-sized patterns in the topological energy landscape at the surface. Support from FOM, NWO and the EU is gratefully acknowledged.
Robust topology optimization of three-dimensional photonic-crystal band-gap structures.
Men, H; Lee, K Y K; Freund, R M; Peraire, J; Johnson, S G
2014-09-22
We perform full 3D topology optimization (in which "every voxel" of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, including fcc (including diamond), bcc, and simple-cubic lattices. Even without imposing the constraints of any fabrication process, the resulting optimal gaps are only slightly larger than previous hand designs, suggesting that current photonic crystals are nearly optimal in this respect. However, optimization can discover new structures, e.g. a new fcc structure with the same symmetry but slightly larger gap than the well known inverse opal, which may offer new degrees of freedom to future fabrication technologies. Furthermore, our band-gap optimization is an illustration of a computational approach to 3D dispersion engineering which is applicable to many other problems in optics, based on a novel semidefinite-program formulation for nonconvex eigenvalue optimization combined with other techniques such as a simple approach to impose symmetry constraints. We also demonstrate a technique for robust topology optimization, in which some uncertainty is included in each voxel and we optimize the worst-case gap, and we show that the resulting band gaps have increased robustness to systematic fabrication errors. PMID:25321732
Robust topology optimization of three-dimensional photonic-crystal band-gap structures
NASA Astrophysics Data System (ADS)
Men, H.; Lee, K. Y. K.; Freund, R. M.; Peraire, J.; Johnson, S. G.
2014-09-01
We perform full 3D topology optimization (in which "every voxel" of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, including fcc (including diamond), bcc, and simple-cubic lattices. Even without imposing the constraints of any fabrication process, the resulting optimal gaps are only slightly larger than previous hand designs, suggesting that current photonic crystals are nearly optimal in this respect. However, optimization can discover new structures, e.g. a new fcc structure with the same symmetry but slightly larger gap than the well known inverse opal, which may offer new degrees of freedom to future fabrication technologies. Furthermore, our band-gap optimization is an illustration of a computational approach to 3D dispersion engineering which is applicable to many other problems in optics, based on a novel semidefinite-program formulation for nonconvex eigenvalue optimization combined with other techniques such as a simple approach to impose symmetry constraints. We also demonstrate a technique for \\emph{robust} topology optimization, in which some uncertainty is included in each voxel and we optimize the worst-case gap, and we show that the resulting band gaps have increased robustness to systematic fabrication errors.
Photonic-band-gap properties for two-component slow light
Ruseckas, J.; Kudriasov, V.; Juzeliunas, G.; Unanyan, R. G.; Otterbach, J.; Fleischhauer, M.
2011-06-15
We consider two-component ''spinor'' slow light in an ensemble of atoms coherently driven by two pairs of counterpropagating control laser fields in a double tripod-type linkage scheme. We derive an equation of motion for the spinor slow light (SSL) representing an effective Dirac equation for a massive particle with the mass determined by the two-photon detuning. By changing the detuning the atomic medium acts as a photonic crystal with a controllable band gap. If the frequency of the incident probe light lies within the band gap, the light experiences reflection from the sample and can tunnel through it. For frequencies outside the band gap, the transmission and reflection probabilities oscillate with the increasing length of the sample. In both cases the reflection takes place into the complementary mode of the probe field. We investigate the influence of the finite excited state lifetime on the transmission and reflection coefficients of the probe light. We discuss possible experimental implementations of the SSL using alkali-metal atoms such as rubidium or sodium.
Liu, Mao Tong; Lim, Han Chuen
2014-09-22
When implementing O-band quantum key distribution on optical fiber transmission lines carrying C-band data traffic, noise photons that arise from spontaneous Raman scattering or insufficient filtering of the classical data channels could cause the quantum bit-error rate to exceed the security threshold. In this case, a photon heralding scheme may be used to reject the uncorrelated noise photons in order to restore the quantum bit-error rate to a low level. However, the secure key rate would suffer unless one uses a heralded photon source with sufficiently high heralding rate and heralding efficiency. In this work we demonstrate a heralded photon source that has a heralding efficiency that is as high as 74.5%. One disadvantage of a typical heralded photon source is that the long deadtime of the heralding detector results in a significant drop in the heralding rate. To counter this problem, we propose a passively spatial-multiplexed configuration at the heralding arm. Using two heralding detectors in this configuration, we obtain an increase in the heralding rate by 37% and a corresponding increase in the heralded photon detection rate by 16%. We transmit the O-band photons over 10 km of noisy optical fiber to observe the relation between quantum bit-error rate and noise-degraded second-order correlation function of the transmitted photons. The effects of afterpulsing when we shorten the deadtime of the heralding detectors are also observed and discussed. PMID:25321795
Zero- n bar band gap in two-dimensional metamaterial photonic crystals
NASA Astrophysics Data System (ADS)
Mejía-Salazar, J. R.; Porras-Montenegro, N.
2015-04-01
We have theoretically studied metamaterial photonic crystals (PCs) composed by air and double negative (DNG) material. Numerical data were obtained by means of the finite difference time-domain (FDTD) method, with results indicating the possibility for the existence of the zero- n bar non-Bragg gap in two-dimensional metamaterial PCs, which has been previously observed only in one-dimensional photonic superlattices. Validity of the present FDTD algorithm for the study of one-dimensional metamaterial PCs is shown by comparing with results for the transmittance spectra obtained by means of the well known transfer matrix method (TMM). In the case of two-dimensional metamaterial PCs, we have calculated the photonic band structure (PBS) in the limiting case of a one-dimensional photonic superlattice and for a nearly one-dimensional PC, showing a very similar dispersion relation. Finally, we show that due to the strong electromagnetic field localization on the constitutive rods, the zero- n bar non-Bragg gap may only exist in two-dimensional systems under strict geometrical conditions.
Acousto-optic modulation of a photonic crystal nanocavity with Lamb waves in microwave K band
Tadesse, Semere A.; Li, Huan; Liu, Qiyu; Li, Mo
2015-11-16
Integrating nanoscale electromechanical transducers and nanophotonic devices potentially can enable acousto-optic devices to reach unprecedented high frequencies and modulation efficiency. Here, we demonstrate acousto-optic modulation of a photonic crystal nanocavity using Lamb waves with frequency up to 19 GHz, reaching the microwave K band. The devices are fabricated in suspended aluminum nitride membrane. Excitation of acoustic waves is achieved with interdigital transducers with period as small as 300 nm. Confining both acoustic wave and optical wave within the thickness of the membrane leads to improved acousto-optic modulation efficiency in these devices than that obtained in previous surface acoustic wave devices. Our system demonstrates a scalable optomechanical platform where strong acousto-optic coupling between cavity-confined photons and high frequency traveling phonons can be explored.
NASA Astrophysics Data System (ADS)
Markel, Vadim A.; Tsukerman, Igor
2016-06-01
We consider conditions under which photonic crystals (PCs) can be homogenized in the higher photonic bands and, in particular, near the Γ point. By homogenization we mean introducing some effective local parameters ɛeff and μeff that describe reflection, refraction, and propagation of electromagnetic waves in the PC adequately. The parameters ɛeff and μeff can be associated with a hypothetical homogeneous effective medium. In particular, if the PC is homogenizable, the dispersion relations and isofrequency lines in the effective medium and in the PC should coincide to some level of approximation. We can view this requirement as a necessary condition of homogenizability. In the vicinity of a Γ point, real isofrequency lines of two-dimensional PCs can be close to mathematical circles, just like in the case of isotropic homogeneous materials. Thus, one may be tempted to conclude that introduction of an effective medium is possible and, at least, the necessary condition of homogenizability holds in this case. We, however, show that this conclusion is incorrect: complex dispersion points must be included into consideration even in the case of strictly nonabsorbing materials. By analyzing the complex dispersion relations and the corresponding isofrequency lines, we have found that two-dimensional PCs with C4 and C6 symmetries are not homogenizable in the higher photonic bands. We also draw a distinction between spurious Γ -point frequencies that are due to Brillouin-zone folding of Bloch bands and "true" Γ -point frequencies that are due to multiple scattering. Understanding of the physically different phenomena that lead to the appearance of spurious and "true" Γ -point frequencies is important for the theory of homogenization.
Askari, Nasim; Eslami, Esmaeil; Mirzaie, Reza
2015-11-15
The photonic band gap of obliquely incident terahertz electromagnetic waves in a one-dimensional plasma photonic crystal is studied. The periodic structure consists of lossless dielectric and inhomogeneous plasma with a parabolic density profile. The dispersion relation and the THz wave transmittance are analyzed based on the electromagnetic equations and transfer matrix method. The dependence of effective plasma frequency and photonic band gap characteristics on dielectric and plasma thickness, plasma density, and incident angle are discussed in detail. A theoretical calculation for effective plasma frequency is presented and compared with numerical results. Results of these two methods are in good agreement.
NASA Astrophysics Data System (ADS)
Rasulov, R. Ya.; Rasulov, V. R.; Eshboltaev, I.
2016-04-01
Matrix elements of optical transitions occuring between the subbands of the valence band of a p-GaAs type semiconductor are calculated. Transitions associated with the non-simultaneous absorption of single photons and simultaneous absorption of two photons are taken into account. The expressions are obtained for the average values of the square modulus of matrix elements calculated with respect to the solid angle of the wave vector of holes. Linear-circular dichroism of four-photon absorption of light in semiconductors with a complex valence band is theoretically studied.
Weather related continuity and completeness on Deep Space Ka-band links: statistics and forecasting
NASA Technical Reports Server (NTRS)
Shambayati, Shervin
2006-01-01
In this paper the concept of link 'stability' as means of measuring the continuity of the link is introduced and through it, along with the distributions of 'good' periods and 'bad' periods, the performance of the proposed Ka-band link design method using both forecasting and long-term statistics has been analyzed. The results indicate that the proposed link design method has relatively good continuity and completeness characteristics even when only long-term statistics are used and that the continuity performance further improves when forecasting is employed. .
Exceptional Contours and Band Structure Design in Parity-Time Symmetric Photonic Crystals
NASA Astrophysics Data System (ADS)
Cerjan, Alexander; Raman, Aaswath; Fan, Shanhui
2016-05-01
We investigate the properties of two-dimensional parity-time symmetric periodic systems whose non-Hermitian periodicity is an integer multiple of the underlying Hermitian system's periodicity. This creates a natural set of degeneracies that can undergo thresholdless P T transitions. We derive a k .p perturbation theory suited to the continuous eigenvalues of such systems in terms of the modes of the underlying Hermitian system. In photonic crystals, such thresholdless P T transitions are shown to yield significant control over the band structure of the system, and can result in all-angle supercollimation, a P T -superprism effect, and unidirectional behavior.
Waveguides in three-dimensional metallic photonic band-gap materials
Sigalas, M.M.; Biswas, R.; Ho, K.M.; Soukoulis, C.M.; Crouch, D.D.
1999-08-01
We theoretically investigate waveguide structures in three-dimensional metallic photonic band-gap (MPBG) materials. The MPBG materials used in this study consist of a three-dimensional mesh of metallic wires embedded in a dielectric. An {ital L}-shaped waveguide is created by removing part of the metallic wires. Using finite difference time domain simulations, we found that an 85{percent} transmission efficiency can be achieved through the 90{degree} bend with just three unit cell thickness MPBG structures. thinsp {copyright} {ital 1999} {ital The American Physical Society}
Research of dual-band microwave photonic filter for WLAN based on optical frequency comb.
Zhang, Qi; Li, Jiaqi; Jiang, Lingke; Pan, Linbing; Dong, Wei; Zhang, Xindong; Ruan, Shengping
2016-07-20
This paper presents a dual-band microwave photonic filter for a wireless local area networks with independently tunable passband center frequencies and bandwidths. The two bands of the filter were 2.4 GHz and 5.725 GHz, respectively. The filter was based on a stimulated Brillouin scattering and an optical frequency comb (OFC) scheme. We created this filter using OFC pumps instead of a single pump. The OFC scheme consists of a cascaded Mach-Zehnder modulator (MZM) and a dual-parallel MZM (DPMZM) hybrid modulation that generated seven and 11 lines. The experimental results show that the two passbands of the filter were 80 and 130 MHz. PMID:27463899
Cross-phase-modulation-instability band gap in a birefringence-engineered photonic-crystal fiber
NASA Astrophysics Data System (ADS)
Kibler, B.; Amrani, F.; Morin, P.; Kudlinski, A.
2016-01-01
We report the cancellation of the cross-phase-modulation-instability (XPMI) gain over a large spectral window (which we term the XPMI band gap) in a highly birefringent photonic-crystal fiber with zero group birefringence. The XPMI ceases to occur when single-frequency pumping of orthogonally polarized modes takes place in such a spectral band gap whose frequency bandwidth depends on the pump power itself. The suppression of XPMI sidebands is confirmed experimentally when Raman scattering remains negligible. At high powers the Raman Stokes wave, generated by the pump, implies novel dual-frequency pump configurations with large group-velocity mismatch, thus leading to another type of Raman-induced XPMI sidebands. The experimental results are in good agreement with analytical phase-matching calculations and numerical simulations.
Band-edge lasing and miniband lasing in 1-D dual-periodic photonic crystal
NASA Astrophysics Data System (ADS)
Ying, Cui-Feng; Zhou, Wen-Yuan; Li, Yi; Ye, Qing; Zhang, Chun-Ping; Tian, Jian-Guo
2012-06-01
Herein, we report two different dual-periodic Photonic Crystals (PCs) in dichromated gelatin emulsion which are fabricated by four-beam holography and double-exposure holography. The minibands with high Q-factors have been evidently located in both two structures. By taking into account the non-uniform distribution of material, the numerical results agree quite well with the experimental results. We also compared the band-edge lasing in single-periodic PC and miniband lasing in Moiré dual-periodic PC. Due to extremely flat dispersion and large mode volume of the miniband, high optical conversion efficiency in miniband lasing is achieved as compared with that of band-edge lasing. Such effect may provide potential applications in low-threshold lasers and ultra-sensitive fluorescent probes in biological assays.
Observation of wakefields in a beam-driven photonic band gap accelerating structure.
Conde, M.; Yusof, Z.; Power, J. G.; Jing, C.; Gao, F.; Antipov, S.; Xu, P.; Zheng, S.; Chen, H.; Tang, C.; Gai, W.; High Energy Physics; Euclid Techlabs LLC; Tsinghua Univ.
2009-12-01
Wakefield excitation has been experimentally studied in a three-cell X-band standing wave photonic band gap (PBG) accelerating structure. Major monopole (TM{sub 01}- and TM{sub 02}-like) and dipole (TM{sub 11}- and TM{sub 12}-like) modes were identified and characterized by precisely controlling the position of beam injection. The quality factor Q of the dipole modes was measured to be {approx}10 times smaller than that of the accelerating mode. A charge sweep, up to 80 nC, has been performed, equivalent to {approx} 30 MV/m accelerating field on axis. A variable delay low charge witness bunch following a high charge drive bunch was used to calibrate the gradient in the PBG structure by measuring its maximum energy gain and loss. Experimental results agree well with numerical simulations.
Nonlinear optical response of semiconductor-nanocrystals-embedded photonic band gap structure
Liao, Chen; Zhang, Huichao; Tang, Luping; Zhou, Zhiqiang; Lv, Changgui; Cui, Yiping; Zhang, Jiayu
2014-04-28
Colloidal CdSe/ZnS core/shell nanocrystals (NCs), which were dispersed in SiO{sub 2} sol, were utilized to fabricate a SiO{sub 2}:NCs/TiO{sub 2} all-dielectric photonic band gap (PBG) structure. The third-order nonlinear refractive index (n{sub 2}) of the PBG structure was nearly triple of that of the SiO{sub 2}:NCs film due to the local field enhancement in the PBG structure. The photoinduced change in refractive index (Δn) could shift the PBG band edge, so the PBG structure would show significant transmission modification, whose transmission change was ∼17 folds of that of the SiO{sub 2}:NCs film. Under excitation of a 30 GW/cm{sup 2} femtosecond laser beam, a transmission decrease of 80% was realized.
Spin polarized photons from an axially charged plasma at weak coupling: Complete leading order
Mamo, Kiminad A.; Yee, Ho-Ung
2016-03-24
In the presence of (approximately conserved) axial charge in the QCD plasma at finite temperature, the emitted photons are spin aligned, which is a unique P- and CP-odd signature of axial charge in the photon emission observables. We compute this “P-odd photon emission rate” in a weak coupling regime at a high temperature limit to complete leading order in the QCD coupling constant: the leading log as well as the constant under the log. As in the P-even total emission rate in the literature, the computation of the P-odd emission rate at leading order consists of three parts: (1) Comptonmore » and pair annihilation processes with hard momentum exchange, (2) soft t- and u-channel contributions with hard thermal loop resummation, (3) Landau-Pomeranchuk-Migdal resummation of collinear bremsstrahlung and pair annihilation. In conclusion, we present analytical and numerical evaluations of these contributions to our P-odd photon emission rate observable.« less
NASA Astrophysics Data System (ADS)
Froufe-Pérez, Luis S.; Engel, Michael; Damasceno, Pablo F.; Muller, Nicolas; Haberko, Jakub; Glotzer, Sharon C.; Scheffold, Frank
2016-07-01
We study photonic band gap formation in two-dimensional high-refractive-index disordered materials where the dielectric structure is derived from packing disks in real and reciprocal space. Numerical calculations of the photonic density of states demonstrate the presence of a band gap for all polarizations in both cases. We find that the band gap width is controlled by the increase in positional correlation inducing short-range order and hyperuniformity concurrently. Our findings suggest that the optimization of short-range order, in particular the tailoring of Bragg scattering at the isotropic Brillouin zone, are of key importance for designing disordered PBG materials.
Froufe-Pérez, Luis S; Engel, Michael; Damasceno, Pablo F; Muller, Nicolas; Haberko, Jakub; Glotzer, Sharon C; Scheffold, Frank
2016-07-29
We study photonic band gap formation in two-dimensional high-refractive-index disordered materials where the dielectric structure is derived from packing disks in real and reciprocal space. Numerical calculations of the photonic density of states demonstrate the presence of a band gap for all polarizations in both cases. We find that the band gap width is controlled by the increase in positional correlation inducing short-range order and hyperuniformity concurrently. Our findings suggest that the optimization of short-range order, in particular the tailoring of Bragg scattering at the isotropic Brillouin zone, are of key importance for designing disordered PBG materials. PMID:27517772
Xu, Donglin; Mock, Ray; Kinard, Gary; Li, Ruhui
2011-08-01
The presence of Gooseberry vein banding associated virus (GVBaV), a badnavirus in the family Caulimoviridae, is strongly correlated with gooseberry vein banding disease in Ribes spp. In this study, full-length genomic sequences of four GVBaV isolates from different hosts and geographic regions were determined to be 7649-7663 nucleotides. These isolates share identities of 96.4-97.3% for the complete genomic sequence, indicating low genetic diversity among them. The GVBaV genome contains three open reading frames (ORFs) on the plus strand that potentially encode proteins of 26, 16, and 216 kDa. The size and organization of GVBaV ORFs 1-3 are similar to those of most other badnaviruses. The putative amino acid sequence of GVBaV ORF 3 contained motifs that are conserved among badnavirus proteins including aspartic protease, reverse transcriptase, and ribonuclease H. The highly conserved putative plant tRNA(met)-binding site is also present in the 935-bp intergenic region of GVBaV. The identities of the genomic sequences of GVBaV and other badnaviruses range from 49.1% (Sugarcane bacilliform Mor virus) to 51.7% (Pelargonium vein banding virus, PVBV). Phylogenetic analysis using the amino acid sequence of the ORF 3 putative protein shows that GVBaV groups most closely to Dioscorea bacilliform virus, PVBV, and Taro bacilliform virus. These results confirm that GVBaV is a pararetrovirus of the genus Badnavirus in the family Caulimoviridae. PMID:21533750
Spectral and polarization structure of field-induced photonic bands in cholesteric liquid crystals
NASA Astrophysics Data System (ADS)
Palto, S. P.; Barnik, M. I.; Geivandov, A. R.; Kasyanova, I. V.; Palto, V. S.
2015-09-01
Transmission of planar layers of cholesteric liquid crystals is studied in pulsed electric fields perpendicular to the helix axis at normal incidence of both linearly polarized and unpolarized light. Spectral and light polarization properties of the primary photonic band and the field-induced bands up to fourth order of Bragg selective reflection are studied in detail. In our experiments we have achieved an electric field strength several times higher than the theoretical values corresponding to the critical field of full helix unwinding. However, the experiments show that despite the high strength of the electric field applied the helix does not unwind, but strongly deforms, keeping its initial spatial period. Strong helix deformation results in distinct spectral band splitting, as well as very high field-induced selective reflectance that can be applied in lasers and other optoelectronic devices. Peculiarities of inducing and splitting the bands are discussed in terms of the scattering coefficient approach. All observed effects are confirmed by numerical simulations. The simulations also show that liquid crystal surface anchoring is not the factor that prevents the helix unwinding. Thus, the currently acknowledged concept of continuous helix unwinding in the electric field should be reconsidered.
Brozell, Adrian M; Muha, Michelle A; Sanii, Babak; Parikh, Atul N
2006-01-11
We report the formation of a new class of supported membranes consisting of a fluid phospholipid bilayer coupled directly to a broadly tunable colloidal crystal with a well-defined photonic band gap. For nanoscale colloidal crystals exhibiting a band gap at the optical frequencies, substrate-induced vesicle fusion gives rise to a surface bilayer riding onto the crystal surface. The bilayer is two-dimensionally continuous, spanning multiple beads with lateral mobilities which reflect the coupling between the bilayer topography and the curvature of the supporting colloidal surface. In contrast, the spreading of vesicles on micrometer scale colloidal crystals results in the formation of bilayers wrapping individual colloidal beads. We show that simple UV photolithography of colloidal crystals produces binary patterns of crystal wettabilities, photonic stopbands, and corresponding patterns of lipid mono- and bilayer morphologies. We envisage that these approaches will be exploitable for the development of optical transduction assays and microarrays for many membrane-mediated processes, including transport and receptor-ligand interactions. PMID:16390122
Periodic dielectric structure for production of photonic band gap and devices incorporating the same
Ho, Kai-Ming; Chan, Che-Ting; Soukoulis, Costas
1994-08-02
A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap. By virtue of forming the device in layers of elongate members, it is found that the device is susceptible of practical construction.
Fabrication of ceramic layer-by-layer infrared wavelength photonic band gap crystals
NASA Astrophysics Data System (ADS)
Kang, Henry Hao-Chuan
Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibiting spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in submicron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers. The goal of this dissertation research is to explore techniques for fabricating 3D ceramic layer-by-layer (LBL) photonic crystals operating in the infrared frequency range, and to characterize the infilling materials properties that affect the fabrication process as well as the structural and optical properties of the crystals. While various approaches have been reported in literature for the fabrication of LBL structure, the uniqueness of this work ties with its cost-efficiency and relatively short process span. Besides, very few works have been reported on fabricating ceramic LBL crystals at mid-IR frequency range so far. The fabrication techniques reported here are mainly based on the concepts of microtransfer molding with the use of polydimethyl siloxane (PDMS) as molds/stamps. The infilling materials studied include titanium alkoxide precursors and aqueous suspensions of nanosize titania particles (slurries). Various infilling materials were synthesized to determine viscosities, effects on drying and firing shrinkages, effects on film surface roughness, and their moldability. Crystallization and phase transformation of the materials were also monitored using DTA, TGA and XRD. Mutilayer crystal
Self-induced transparency solitary waves in a doped nonlinear photonic band gap material
NASA Astrophysics Data System (ADS)
Aközbek, Neşet; John, Sajeev
1998-09-01
We derive the properties of self-induced transparency (SIT) solitary waves in a one-dimensional periodic structure doped uniformly with resonance two-level atoms. In our model, the electromagnetic field is treated classically and the dopant atoms are described quantum mechanically. The resulting solitary waves take the form of ultrashort (picosecond) laser pulses which propagate near the band edge of the nonlinear photonic band gap (PBG) material doped with rare-earth atoms such as erbium. Solitary wave formation involves the combined effects of group velocity dispersion (GVD), nonresonant Kerr nonlinearity, and resonant interaction with dopant atoms. We derive the general Maxwell-Bloch equations for a nonlinear PBG system and then demonstrate the existence of elementary solitary wave solutions for frequencies far outside the gap where GVD effects are negligible and for frequencies near the photonic band edge where GVD effects are crucial. We find two distinct new types of propagating SIT solitary wave pulses. Far from Bragg resonance, we recapture the usual McCall-Hahn soliton with hyperbolic secant profile when the nonlinear Kerr coefficient χ(3)=0. However, when the host nonresonant Kerr coefficient is nonzero, we obtain the first new type of soliton. In this case, the optical soliton envelope function deviates from the hyperbolic secant profile and pulse propagation requires nontrivial phase modulation (chirping). We derive the dependence of the solitary wave structure on the Kerr coefficient χ(3), the resonance impurity atom density, and the detuning of the average laser frequency from the atomic transition. When the laser frequency and the atomic transition frequencies are near the photonic band edge we obtain the second type of soliton. To illustrate the second type of soliton we consider two special cases. In the first case, GVD facilitates the propagation of an unchirped SIT-gap soliton moving at a velocity fixed by the material's parameters. The soliton
Wave propagation in ordered, disordered, and nonlinear photonic band gap materials
Lidorikis, Elefterios
1999-12-10
Photonic band gap materials are artificial dielectric structures that give the promise of molding and controlling the flow of optical light the same way semiconductors mold and control the electric current flow. In this dissertation the author studied two areas of photonic band gap materials. The first area is focused on the properties of one-dimensional PBG materials doped with Kerr-type nonlinear material, while, the second area is focused on the mechanisms responsible for the gap formation as well as other properties of two-dimensional PBG materials. He first studied, in Chapter 2, the general adequacy of an approximate structure model in which the nonlinearity is assumed to be concentrated in equally-spaced very thin layers, or 6-functions, while the rest of the space is linear. This model had been used before, but its range of validity and the physical reasons for its limitations were not quite clear yet. He performed an extensive examination of many aspects of the model's nonlinear response and comparison against more realistic models with finite-width nonlinear layers, and found that the d-function model is quite adequate, capturing the essential features in the transmission characteristics. The author found one exception, coming from the deficiency of processing a rigid bottom band edge, i.e. the upper edge of the gaps is always independent of the refraction index contrast. This causes the model to miss-predict that there are no soliton solutions for a positive Kerr-coefficient, something known to be untrue.
Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can
2016-01-01
Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems. PMID:27225881
NASA Astrophysics Data System (ADS)
Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can
2016-05-01
Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems.
Chen, Geng; Zou, Yang; Zhang, Wen-Hao; Zhang, Zi-Huai; Zhou, Zong-Quan; He, De-Yong; Tang, Jian-Shun; Liu, Bi-Heng; Yu, Ying; Zha, Guo-Wei; Ni, Hai-Qiao; Niu, Zhi-Chuan; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can
2016-01-01
Quantum emitters generating individual entangled photon pairs (IEPP) have significant fundamental advantages over schemes that suffer from multiple photon emission, or schemes that require post-selection techniques or the use of photon-number discriminating detectors. Quantum dots embedded within nanowires (QD-NWs) represent one of the most promising candidate for quantum emitters that provide a high collection efficiency of photons. However, a quantum emitter that generates IEPP in the telecom band is still an issue demanding a prompt solution. Here, we demonstrate in principle that IEPPs in the telecom band can be created by combining a single QD-NW and a nonlinear crystal waveguide. The QD-NW system serves as the single photon source, and the emitted visible single photons are split into IEPPs at approximately 1.55 μm through the process of spontaneous parametric down conversion (SPDC) in a periodically poled lithium niobate (PPLN) waveguide. The compatibility of the QD-PPLN interface is the determinant factor in constructing this novel hybrid-quantum-emitter (HQE). Benefiting from the desirable optical properties of QD-NWs and the extremely high nonlinear conversion efficiency of PPLN waveguides, we successfully generate IEPPs in the telecom band with the polarization degree of freedom. The entanglement of the generated photon pairs is confirmed by the entanglement witness. Our experiment paves the way to producing HQEs inheriting the advantages of multiple systems. PMID:27225881
Shin, Young-Min
2012-05-15
Confined propagation of guided waves through the periodically corrugated channel sandwiched between two staggered dielectric photonic-band-gap slab arrays is investigated with the band-response analysis. Numerical simulations show that longitudinally polarized evanescent waves within the band gap propagate with insertion loss of {approx}-0.2 to 1 dB (-0.05 to 0.4 dB/mm at G-band) in the hybrid band filter. This structure significantly suppresses low energy modes and higher-order-modes beyond the band-gap, including background noises, down to {approx}-45 dB. This would enable the single-mode propagation in the heavily over-moded waveguide (TEM-type), minimizing abnormal excitation probability of trapped modes. This band filter could be integrated with active and passive RF components for electron beam and optoelectronic devices.
Design of full-k-space flat bands in photonic crystals beyond the tight-binding picture
Xu, Changqing; Wang, Gang; Hang, Zhi Hong; Luo, Jie; Chan, C. T.; Lai, Yun
2015-01-01
Based on a band engineering method, we propose a theoretical prescription to create a full-k-space flat band in dielectric photonic crystals covering the whole Brillouin Zone. With wave functions distributed in air instead of in the dielectrics, such a flat band represents a unique mechanism for achieving flat dispersions beyond the tight-binding picture, which can enormously reduce the requirement of permittivity contrast in the system. Finally, we propose and numerically demonstrate a unique application based on the full-k-space coverage of the flat band: ultra-sensitive detection of small scatterers. PMID:26656882
The Development of Layered Photonic Band Gap Structures Using a Micro-Transfer Molding Technique
Kevin Jerome Sutherland
2001-06-27
Over the last ten years, photonic band gap (PBG) theory and technology have become an important area of research because of the numerous possible applications ranging from high-efficiency laser diodes to optical circuitry. This research concentrates on reducing the length scale in the fabrication of layered photonic band gap structures and developing procedures to improve processing consistency. Various procedures and materials have been used in the fabrication of layered PBG structures. This research focused on an economical micro transfer molding approach to create the final PBG structure. A poly dimethylsiloxane (PDMS) rubber mold was created from a silicon substrate. It was filled with epoxy and built layer-by-layer to create a 3-D epoxy structure. This structure was infiltrated with nanoparticle titania or a titania sol-gel, then fired to remove the polymer mold, leaving a monolithic ceramic inverse of the epoxy structure. The final result was a lattice of titania rolds that resembles a face-centered tetragonal structure. The original intent of this research was to miniaturize this process to a bar size small enough to create a photonic band gap for wavelengths of visible electro-magnetic radiation. The factor limiting progress was the absence of a silicon master mold of small enough dimensions. The Iowa State Microelectronics Research Center fabricated samples with periodicities of 2.5 and 1.0 microns with the existing technology, but a sample was needed on the order of 0.3 microns or less. A 0.4 micron sample was received from Sandia National Laboratory, which was made through an electron beam lithography process, but it contained several defects. The results of the work are primarily from the 2.5 and 1.0 micron samples. Most of the work focused on changing processing variables in order to optimize the infiltration procedure for the best results. Several critical parameters were identified, ranging from the ambient conditions to the specifics of the
Becker, C; Lockau, D; Sontheimer, T; Schubert-Bischoff, P; Rudigier-Voigt, E; Bockmeyer, M; Schmidt, F; Rech, B
2012-04-01
Two-dimensional silicon nanodome arrays are prepared on large areas up to 50 cm² exhibiting photonic band structure effects in the near-infrared and visible wavelength region by downscaling a recently developed fabrication method based on nanoimprint-patterned glass, high-rate electron-beam evaporation of silicon, self-organized solid phase crystallization and wet-chemical etching. The silicon nanodomes, arranged in square lattice geometry with 300 nm lattice constant, are optically characterized by angular resolved reflection measurements, allowing the partial determination of the photonic band structure. This experimentally determined band structure agrees well with the outcome of three-dimensional optical finite-element simulations. A 16% photonic bandgap is predicted for an optimized geometry of the silicon nanodome arrays. By variation of the duration of the selective etching step, the geometry as well as the optical properties of the periodic silicon nanodome arrays can be controlled systematically. PMID:22422473
NASA Astrophysics Data System (ADS)
Chern, R. L.; Chang, C. Chung; Chang, Chien C.; Hwang, R. R.
2003-08-01
In this study, two fast and accurate methods of inverse iteration with multigrid acceleration are developed to compute band structures of photonic crystals of general shape. In particular, we report two-dimensional photonic crystals of silicon air with an optimal full band gap of gap-midgap ratio Δω/ωmid=0.2421, which is 30% larger than ever reported in the literature. The crystals consist of a hexagonal array of circular columns, each connected to its nearest neighbors by slender rectangular rods. A systematic study with respect to the geometric parameters of the photonic crystals was made possible with the present method in drawing a three-dimensional band-gap diagram with reasonable computing time.
Chern, R L; Chang, C Chung; Chang, Chien C; Hwang, R R
2003-08-01
In this study, two fast and accurate methods of inverse iteration with multigrid acceleration are developed to compute band structures of photonic crystals of general shape. In particular, we report two-dimensional photonic crystals of silicon air with an optimal full band gap of gap-midgap ratio Deltaomega/omega(mid)=0.2421, which is 30% larger than ever reported in the literature. The crystals consist of a hexagonal array of circular columns, each connected to its nearest neighbors by slender rectangular rods. A systematic study with respect to the geometric parameters of the photonic crystals was made possible with the present method in drawing a three-dimensional band-gap diagram with reasonable computing time. PMID:14525145
Optical crosstalk in single photon avalanche diode arrays: a new complete model.
Rech, Ivan; Ingargiola, Antonino; Spinelli, Roberto; Labanca, Ivan; Marangoni, Stefano; Ghioni, Massimo; Cova, Sergio
2008-06-01
One of the main issues of Single Photon Avalanche Diode arrays is optical crosstalk. Since its intensity increases with reducing the distance between devices, this phenomenon limits the density of integration within arrays. In the past optical crosstalk was ascribed essentially to the light propagating from one detector to another through direct optical paths. Accordingly, reflecting trenches between devices were proposed to prevent it, but they proved to be not completely effective. In this paper we will present experimental evidence that a significant contribution to optical crosstalk comes from light reflected internally off the bottom of the chip, thus being impossible to eliminate it completely by means of trenches. We will also propose an optical model to predict the dependence of crosstalk on the distance between devices. PMID:18545552
Lai, Chun-Feng; Chang, Chung-Chieh; Wang, Ming-Jye; Wu, Mau-Kuen
2013-07-01
This study exhibited the correlated color temperature (CCT)- and color-rendering index (CRI)-tuning behavior of light emission from white light-emitting diodes (WLEDs) using three-dimensional non-close-packed (3D NCP) colloidal photonic crystals (CPhCs). The CCT of approximately 5300 K (characteristic of cold WLEDs) of white light propagated through the NCP CPhCs dropped to 3000 K (characteristic of warm WLEDs) because of the photonic stop-bands based on the photonic band structures of NCP CPhCs. This study successfully developed a novel technique that introduces lower-cost CCT- and CRI-tuning cold WLEDs with a CRI of over 90 that of warm WLEDs by using 3D NCP CPhCs. PMID:24104495
NASA Astrophysics Data System (ADS)
González, Luz E.; Porras-Montenegro, N.
2012-01-01
In this work using the transfer-matrix formalism we study pressure, temperature and plasma frequency effects on the band structure of a 1D semiconductor photonic crystal made of alternating layers of air and GaAs. We have found that the temperature dependence of the photonic band structure is negligible, however, its noticeable changes are due mainly to the variations of the width and the dielectric constant of the layers of GaAs, caused by the applied hydrostatic pressure. On the other hand, by using the Drude's model, we have studied the effects of the hydrostatic pressure by means of the variation of the effective mass and density of the carriers in n-doped GaAs, finding firstly that increasing the amount of n-dopants in GaAs, namely, increasing the plasma frequency, the photonic band structure is shifted to regions of higher frequencies, and secondly the appearance of two regimes of the photonic band structure: one above the plasma frequency with the presence of usual Bragg gaps, and the other, below this frequency, where there are no gaps regularly distributed, with their width diminishing with the increasing of the plasma frequency as well as with the appearance of more bands, but leaving a wide frequency range in the lowest part of the spectrum without accessible photon states. Also, we have found characteristic frequencies in which the dielectric constant equals for different applied pressures, and from which to higher or lower values the photonic band structure inverts its behavior, depending on the value of the applied hydrostatic pressure. We hope this work may be taken into account for the development of new perspectives in the design of new optical devices.
Structural Coloration of Colloidal Fiber by Photonic Band Gap and Resonant Mie Scattering.
Yuan, Wei; Zhou, Ning; Shi, Lei; Zhang, Ke-Qin
2015-07-01
Because structural color is fadeless and dye-free, structurally colored materials have attracted great attention in a wide variety of research fields. In this work, we report the use of a novel structural coloration strategy applied to the fabrication of colorful colloidal fibers. The nanostructured fibers with tunable structural colors were massively produced by colloidal electrospinning. Experimental results and theoretical modeling reveal that the homogeneous and noniridescent structural colors of the electrospun fibers are caused by two phenomena: reflection due to the band gap of photonic structure and Mie scattering of the colloidal spheres. Our unprecedented findings show promise in paving way for the development of revolutionary dye-free technology for the coloration of various fibers. PMID:26066732
Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber
NASA Astrophysics Data System (ADS)
Ramzia Salem, A. M.; Al-Mansoori, M. H.; Hizam, H.; Mohd Noor, S. B.; Abu Bakar, M. H.; Mahdi, M. A.
2011-05-01
A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm.
Liu, Lei; Qu, Hongwei; Liu, Yun; Zhang, Yejin; Zheng, Wanhua; Wang, Yufei; Qi, Aiyi
2014-12-08
900 nm longitudinal photonic band crystal (PBC) laser diodes with optimized epitaxial structure are fabricated. With a same calculated fundamental-mode divergence, stronger mode discrimination is achieved by a quasi-periodic index modulation in the PBC waveguide than a periodic one. Experiments show that the introduction of over 5.5 μm-thick PBC waveguide contributes to only 10% increment of the internal loss for the laser diodes. For broad area PBC lasers, output powers of 5.75 W under continuous wave test and over 10 W under quasi-continuous wave test are reported. The vertical divergence angles are 10.5° at full width at half maximum and 21.3° with 95% power content, in conformity with the simulated angles. Such device shows a prospect for high-power narrow-vertical-divergence laser emission from single diode laser and laser bar.
Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure
Simakov, Evgenya I.; Arsenyev, Sergey A.; Buechler, Cynthia E.; Edwards, Randall L.; Romero, William P.; Conde, Manoel; Ha, Gwanghui; Power, John G.; Wisniewski, Eric E.; Jing, Chunguang
2016-02-10
We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic band gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. Wemore » conducted an experiment at the Argonne Wakefield Accelerator (AWA) test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Lastly, excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test.« less
Accessing quadratic nonlinearities of metals through metallodielectric photonic-band-gap structures.
D'Aguanno, Giuseppe; Mattiucci, Nadia; Bloemer, Mark J; Scalora, Michael
2006-09-01
We study second harmonic generation in a metallodielectric photonic-band-gap structure made of alternating layers of silver and a generic, dispersive, linear, dielectric material. We find that under ideal conditions the conversion efficiency can be more than two orders of magnitude greater than the maximum conversion efficiency achievable in a single layer of silver. We interpret this enhancement in terms of the simultaneous availability of phase matching conditions over the structure and good field penetration into the metal layers. We also give a realistic example of a nine-period, Si3/N4Ag stack, where the backward conversion efficiency is enhanced by a factor of 50 compared to a single layer of silver. PMID:17025762
Observation of Wakefield Suppression in a Photonic-Band-Gap Accelerator Structure.
Simakov, Evgenya I; Arsenyev, Sergey A; Buechler, Cynthia E; Edwards, Randall L; Romero, William P; Conde, Manoel; Ha, Gwanghui; Power, John G; Wisniewski, Eric E; Jing, Chunguang
2016-02-12
We report experimental observation of higher order mode (HOM) wakefield suppression in a room-temperature traveling-wave photonic-band-gap (PBG) accelerating structure at 11.700 GHz. It has been long recognized that PBG structures have the potential for reducing long-range wakefields in accelerators. The first ever demonstration of acceleration in a room-temperature PBG structure was conducted in 2005. Since then, the importance of PBG accelerator research has been recognized by many institutions. However, the full experimental characterization of the wakefield spectrum and demonstration of wakefield suppression when the accelerating structure is excited by an electron beam has not been performed to date. We conducted an experiment at the Argonne Wakefield Accelerator test facility and observed wakefields excited by a single high charge electron bunch when it passes through a PBG accelerator structure. Excellent HOM suppression properties of the PBG accelerator were demonstrated in the beam test. PMID:26918995
Pushing the Gradient Limitations of Superconducting Photonic Band Gap Structure Cells
Simakov, Evgenya I.; Haynes, William B.; Kurennoy, Sergey S.; Shchegolkov, Dmitry; O'Hara, James F.; Olivas, Eric R.
2012-06-07
Superconducting photonic band gap resonators present us with unique means to place higher order mode couples in an accelerating cavity and efficiently extract HOMs. An SRF PBG resonator with round rods was successfully tested at LANL demonstrating operation at 15 MV/m. Gradient in the SRF PBG resonator was limited by magnetic quench. To increase the quench threshold in PBG resonators one must design the new geometry with lower surface magnetic fields and preserve the resonator's effectiveness for HOM suppression. The main objective of this research is to push the limits for the high-gradient operation of SRF PBG cavities. A NCRF PBG cavity technology is established. The proof-of-principle operation of SRF PBG cavities is demonstrated. SRF PBG resonators are effective for outcoupling HOMs. PBG technology can significantly reduce the size of SRF accelerators and increase brightness for future FELs.
New method for computation of band structures in 1D photonic crystals based on the Fresnel equations
NASA Astrophysics Data System (ADS)
Roshan Entezar, S.
2013-02-01
In this paper, we present a new method for calculation of band structure in one-dimensional bilayer photonic crystals, based on the Fresnel equations. We derive a new relation to obtain the band structure without using the Floquet theorem. It is shown that this relation can be simplified under the assumption that the single-path phase-shift acquired through the individual layers of the photonic crystal be equal to ? . The results obtained by our method are compared with the ones obtained from the transfer matrix method to show that they are exactly identical.
Experimental high gradient testing of a 17.1 GHz photonic band-gap accelerator structure
NASA Astrophysics Data System (ADS)
Munroe, Brian J.; Zhang, JieXi; Xu, Haoran; Shapiro, Michael A.; Temkin, Richard J.
2016-03-01
We report the design, fabrication, and high gradient testing of a 17.1 GHz photonic band-gap (PBG) accelerator structure. Photonic band-gap (PBG) structures are promising candidates for electron accelerators capable of high-gradient operation because they have the inherent damping of high order modes required to avoid beam breakup instabilities. The 17.1 GHz PBG structure tested was a single cell structure composed of a triangular array of round copper rods of radius 1.45 mm spaced by 8.05 mm. The test assembly consisted of the test PBG cell located between conventional (pillbox) input and output cells, with input power of up to 4 MW from a klystron supplied via a TM01 mode launcher. Breakdown at high gradient was observed by diagnostics including reflected power, downstream and upstream current monitors and visible light emission. The testing procedure was first benchmarked with a conventional disc-loaded waveguide structure, which reached a gradient of 87 MV /m at a breakdown probability of 1.19 ×10-1 per pulse per meter. The PBG structure was tested with 100 ns pulses at gradient levels of less than 90 MV /m in order to limit the surface temperature rise to 120 K. The PBG structure reached up to 89 MV /m at a breakdown probability of 1.09 ×10-1 per pulse per meter. These test results show that a PBG structure can simultaneously operate at high gradients and low breakdown probability, while also providing wakefield damping.
NASA Astrophysics Data System (ADS)
Funk, O.; Pfeilsticker, K.
2003-03-01
This paper addresses the statistics underlying cloudy sky radiative transfer (RT) by inspection of the distribution of the path lengths of solar photons. Recent studies indicate that this approach is promising, since it might reveal characteristics about the diffusion process underlying atmospheric radiative transfer (Pfeilsticker, 1999). Moreover, it uses an observable that is directly related to the atmospheric absorption and, therefore, of climatic relevance. However, these studies are based largely on the accuracy of the measurement of the photon path length distribution (PPD). This paper presents a refined analysis method based on high resolution spectroscopy of the oxygen A-band. The method is validated by Monte Carlo simulation atmospheric spectra. Additionally, a new method to measure the effective optical thickness of cloud layers, based on fitting the measured differential transmissions with a 1-dimensional (discrete ordinate) RT model, is presented. These methods are applied to measurements conducted during the cloud radar inter-comparison campaign CLARE’98, which supplied detailed cloud structure information, required for the further analysis. For some exemplary cases, measured path length distributions and optical thicknesses are presented and backed by detailed RT model calculations. For all cases, reasonable PPDs can be retrieved and the effects of the vertical cloud structure are found. The inferred cloud optical thicknesses are in agreement with liquid water path measurements.
High-power picosecond pulse delivery through hollow core photonic band gap fibers
NASA Astrophysics Data System (ADS)
Michieletto, Mattia; Johansen, Mette M.; Lyngsø, Jens K.; Lægsgaard, Jesper; Bang, Ole; Alkeskjold, Thomas T.
2016-03-01
We demonstrated robust and bend insensitive fiber delivery of high power laser with diffraction limited beam quality for two different kinds of hollow core band gap fibers. The light source for this experiment consists of ytterbium-doped double clad fiber aeroGAIN-ROD-PM85 in a high power amplifier setup. It provided 22ps pulses with a maximum average power of 95W, 40MHz repetition rate at 1032nm (~2.4μJ pulse energy), with M2 <1.3. We determined the facet damage threshold for a 7-cells hollow core photonic bandgap fiber and showed up to 59W average power output for a 5 meters fiber. The damage threshold for a 19-cell hollow core photonic bandgap fiber exceeded the maximum power provided by the light source and up to 76W average output power was demonstrated for a 1m fiber. In both cases, no special attention was needed to mitigate bend sensitivity. The fibers were coiled on 8 centimeters radius spools and even lower bending radii were present. In addition, stimulated rotational Raman scattering arising from nitrogen molecules was measured through a 42m long 19 cell hollow core fiber.
Wide-band acousto-optic deflectors for large field of view two-photon microscope.
Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun
2012-04-01
Acousto-optic deflector (AOD) is an attractive scanner for two-photon microscopy because it can provide fast and versatile laser scanning and does not involve any mechanical movements. However, due to the small scan range of available AOD, the field of view (FOV) of the AOD-based microscope is typically smaller than that of the conventional galvanometer-based microscope. Here, we developed a novel wide-band AOD to enlarge the scan angle. Considering the maximum acceptable acoustic attenuation in the acousto-optic crystal, relatively lower operating frequencies and moderate aperture were adopted. The custom AOD was able to provide 60 MHz 3-dB bandwidth and 80% peak diffraction efficiency at 840 nm wavelength. Based on a pair of such AOD, a large FOV two-photon microscope was built with a FOV up to 418.5 μm (40× objective). The spatiotemporal dispersion was compensated simultaneously with a single custom-made prism. By means of dynamic power modulation, the variation of laser intensity within the FOV was reduced below 5%. The lateral and axial resolution of the system were 0.58-2.12 μm and 2.17-3.07 μm, respectively. Pollen grain images acquired by this system were presented to demonstrate the imaging capability at different positions across the entire FOV. PMID:22559541
Two-photon absorption cross section measurement in the gamma band system of nitric oxide
Burris, J.F. Jr.
1982-01-01
A dye laser with a single longitudinal mode and very stable spatial mode structure has been constructed. With this laser system a four-wave mixing experiment was done in the gamma bands of nitric oxide using two photon resonance. Another four-wave mixing experiment was done in nitrogen using coherent anti-Stokes Raman scattering (CARS) and the two signals ratioed. Using accurately known values of the Raman scattering cross section, the third order susceptibility in NO was determined without needing to know the spatial and temporal properties of the dye lasers. From this susceptibility, the two photon absorption cross section was calculated with the explicit dependence of sigma/sup (2)/ upon X/sup (3)/ shown. For the R/sub 22/ + S/sub 12/(J'' = 9 1/2) (A/sup 2/..sigma..+(v' = 0) -- X/sup 2/..pi..(v'' = 0)) line, sigma/sup (2)/ = (1.0 +/- 0.6) x 10/sup -38/cm/sup 4/g(2/sub 1/-Vertical Barsub f/ is the normalized lineshape. Branching ratios for the A/sup 2/..sigma..+(v' = n) ..-->.. X/sup 2/..omega..(v'' = n)(n = o,...9) transitions of NO were also measured, Franck-Condon factors calculated and the lifetime of the A state determined.
Singh, A.; Huisman, S. R.; Ctistis, G. Mosk, A. P.; Pinkse, P. W. H.; Korterik, J. P.; Herek, J. L.
2015-01-21
We have measured the photonic bandstructure of GaAs photonic-crystal waveguides with high resolution in energy as well as in momentum using near-field scanning optical microscopy. Intriguingly, we observe additional bands that are not predicted by eigenmode solvers, as was recently demonstrated by Huisman et al. [Phys. Rev. B 86, 155154 (2012)]. We study the presence of these additional bands by performing measurements of these bands while varying the incident light power, revealing a non-linear power dependence. Here, we demonstrate experimentally and theoretically that the observed additional bands are caused by a waveguide-specific near-field tip effect not previously reported, which can significantly phase-modulate the detected field.
NASA Astrophysics Data System (ADS)
Singh, A.; Ctistis, G.; Huisman, S. R.; Korterik, J. P.; Mosk, A. P.; Herek, J. L.; Pinkse, P. W. H.
2015-01-01
We have measured the photonic bandstructure of GaAs photonic-crystal waveguides with high resolution in energy as well as in momentum using near-field scanning optical microscopy. Intriguingly, we observe additional bands that are not predicted by eigenmode solvers, as was recently demonstrated by Huisman et al. [Phys. Rev. B 86, 155154 (2012)]. We study the presence of these additional bands by performing measurements of these bands while varying the incident light power, revealing a non-linear power dependence. Here, we demonstrate experimentally and theoretically that the observed additional bands are caused by a waveguide-specific near-field tip effect not previously reported, which can significantly phase-modulate the detected field.
A super narrow band filter based on silicon 2D photonic crystal resonator and reflectors
NASA Astrophysics Data System (ADS)
Wang, Yuanyuan; Chen, Deyuan; Zhang, Gang; Wang, Juebin; Tao, Shangbin
2016-03-01
In this paper, a novel structure of super narrow band filter based on two-dimensional square lattice photonic crystals of silicon rods in air for 1.5 um communication is proposed and studied. COMSOL Multiphysics4.3b software is used to simulate the optical behavior of the filter. The filter consists of one point-defect-based resonator and two line-defect-based reflectors. The resonance frequency, transmission coefficient and quality factor are investigated by varying the parameters of the structure. In design, a silicon rod is removed to form the resonator; for the rows of rods above and below the resonator, a part of the rods are removed to form the reflectors. By optimizing the parameters of the filter, the quality factor and transmission coefficient of the filter at the resonance frequency of 2e14 Hz can reach 1330 and 0.953, respectively. The super narrow band filter can be integrated into optical circuit for its micron size. Also, it can be used for wavelength selection and noise filtering of optical amplifier in future communication application.
Photonically enabled Ka-band radar and infrared sensor subscale testbed
NASA Astrophysics Data System (ADS)
Lohr, Michele B.; Sova, Raymond M.; Funk, Kevin B.; Airola, Marc B.; Dennis, Michael L.; Pavek, Richard E.; Hollenbeck, Jennifer S.; Garrison, Sean K.; Conard, Steven J.; Terry, David H.
2014-10-01
A subscale radio frequency (RF) and infrared (IR) testbed using novel RF-photonics techniques for generating radar waveforms is currently under development at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to study target scenarios in a laboratory setting. The linearity of Maxwell's equations allows the use of millimeter wavelengths and scaled-down target models to emulate full-scale RF scene effects. Coupled with passive IR and visible sensors, target motions and heating, and a processing and algorithm development environment, this testbed provides a means to flexibly and cost-effectively generate and analyze multi-modal data for a variety of applications, including verification of digital model hypotheses, investigation of correlated phenomenology, and aiding system capabilities assessment. In this work, concept feasibility is demonstrated for simultaneous RF, IR, and visible sensor measurements of heated, precessing, conical targets and of a calibration cylinder. Initial proof-of-principle results are shown of the Ka-band subscale radar, which models S-band for 1/10th scale targets, using stretch processing and Xpatch models.
Efficient photon extraction from a quantum dot in a broad-band planar cavity antenna
Ma, Yong Kremer, Peter E.; Gerardot, Brian D.
2014-01-14
We analyse the extraction of photons emitted from single InAs quantum dots embedded in planar microcavities. The structures are designed to achieve broad-band operation and high-collection efficiency from a device requiring straightforward fabrication, even with electrical contacts. The designs consist of a quantum dot in a GaAs membrane with asymmetric top and bottom mirrors and a top-side solid immersion lens (SIL). Four separate cases are considered in our design: a GaAs membrane only (case 1), GaAs membrane with a glass SIL on top (case 2), a GaAs membrane with a glass SIL on top and a back mirror consisting of Au (case 3), a GaAs membrane with a glass SIL on top of a distribute Bragg reflector mirror and Au back mirror (case 4). Both finite difference time domain and analytical simulations are used to calculate the electric field, power density, and far-field radiation pattern. For optimized structures (case 4), we obtain significant extraction efficiencies (>50%) with modest Purcell enhancements (∼20%) and a large spectral full-width-half-maximum (>100 nm). The high-extraction efficiency, broad-band operation, and facile fabrication make the proposed structures promising for realistic quantum dot devices.
Efficient photon extraction from a quantum dot in a broad-band planar cavity antenna
NASA Astrophysics Data System (ADS)
Ma, Yong; Kremer, Peter E.; Gerardot, Brian D.
2014-01-01
We analyse the extraction of photons emitted from single InAs quantum dots embedded in planar microcavities. The structures are designed to achieve broad-band operation and high-collection efficiency from a device requiring straightforward fabrication, even with electrical contacts. The designs consist of a quantum dot in a GaAs membrane with asymmetric top and bottom mirrors and a top-side solid immersion lens (SIL). Four separate cases are considered in our design: a GaAs membrane only (case 1), GaAs membrane with a glass SIL on top (case 2), a GaAs membrane with a glass SIL on top and a back mirror consisting of Au (case 3), a GaAs membrane with a glass SIL on top of a distribute Bragg reflector mirror and Au back mirror (case 4). Both finite difference time domain and analytical simulations are used to calculate the electric field, power density, and far-field radiation pattern. For optimized structures (case 4), we obtain significant extraction efficiencies (>50%) with modest Purcell enhancements (˜20%) and a large spectral full-width-half-maximum (>100 nm). The high-extraction efficiency, broad-band operation, and facile fabrication make the proposed structures promising for realistic quantum dot devices.
Complete Analysis of Four-Photon χ-Type Entangled State via Cross-Kerr Nonlinearity
NASA Astrophysics Data System (ADS)
Zeng, Zhi; Li, Xi-Han; Wang, Chun; Wang, Li-Li; Liu, Zhen-Zhen; Wei, Hua
2015-09-01
We propose an efficient method to construct an optical four-photon |χ> state analyzer via the cross-Kerr nonlinearity combined with linear optical elements. In this protocol, two four-qubit parity-check gates and two controlled phase gates are employed. We show that all the 16 orthogonal four-qubit |χ> states can be completely discriminated with our apparatus. The scheme is feasible and realizable with current technology. It may have useful potential applications in quantum information processing which based on |χ> state. Supported by the National Natural Science Foundation of China under Grant No. 11004258, and Fundamental Research Funds for the Central Universities Project under Grant No. CQDXWL-2012-014, the Natural Science Foundation Project of CQ CSTC 2011jjA90017
NASA Astrophysics Data System (ADS)
Li, Xinying; Yu, Jianjun; Zhang, Ziran; Xiao, Jiangnan; Chang, Gee-Kung
2015-08-01
We propose photonic vector signal generation at millimeter-wave (mm-wave) bands enabled by a single Mach-Zehnder modulator (MZM) and phase-precoding technique, which can realize photonic frequency multiplication of the precoded microwave vector signal used for the drive of the single MZM. We also experimentally demonstrate the generation of quadrature-phase-shift-keying (QPSK) modulated vector signal at W-band adopting photonic frequency octupling (×8) based on our proposed scheme. The MZM is driven by a 12-GHz QPSK modulated precoded vector signal. Up to 4-Gbaud QPSK-modulated electrical vector signal at 96 GHz is generated and then delivered over 3-m wireless transmission distance.
Meng, Jiaorong; Liu, Pingping; Zhu, Liling; Zou, Chengwu; Li, Jieqiu; Chen, Baoshan
2015-01-01
Mulberry vein banding associated virus (MVBaV) that infects mulberry plants with typical vein banding symptoms had been identified as a tentative species of the genus Tospovirus based on the homology of N gene sequence to those of tospoviruses. In this study, the complete sequence of the tripartite RNA genome of MVBaV was determined and analyzed. The L RNA has 8905 nucleotides (nt) and encodes the putative RNA-dependent RNA polymerase (RdRp) of 2877 aa amino acids (aa) in the viral complementary (vc) strand. The RdRp of MVBaV shares the highest aa sequence identity (85.9%) with that of Watermelon silver mottle virus (WSMoV), and contains conserved motifs shared with those of the species of the genus Tospovirus. The M RNA contains 4731 nt and codes in ambisense arrangement for the NSm protein of 309 aa in the sense strand and the Gn/Gc glycoprotein precursor (GP) of 1,124 aa in the vc strand. The NSm and GP of MVBaV share the highest aa sequence identities with those of Capsicum chlorosis virus (CaCV) and Groundnut bud necrosis virus (GBNV) (83.2% and 84.3%, respectively). The S RNA is 3294 nt in length and contains two open reading frames (ORFs) in an ambisense coding strategy, encoding a 439-aa non-structural protein (NSs) and the 277-aa nucleocapsid protein (N), respectively. The NSs and N also share the highest aa sequence identity (71.1% and 74.4%, respectively) with those of CaCV. Phylogenetic analysis of the RdRp, NSm, GP, NSs, and N proteins showed that MVBaV is most closely related to CaCV and GBNV and that these proteins cluster with those of the WSMoV serogroup, and that MVBaV seems to be a species bridging the two subgroups within the WSMoV serogroup of tospoviruses in evolutionary aspect, suggesting that MVBaV represents a distinct tospovirus. Analysis of S RNA sequence uncovered the highly conserved 5’-/3’-ends and the coding regions, and the variable region of IGR with divergent patterns among MVBaV isolates. PMID:26291718
Influence of photonic stop band effect on photoluminescence of Y 2O 3:Eu 3+ inverse opal films
NASA Astrophysics Data System (ADS)
Qu, Xuesong; Dong, Biao; Pan, Guohui; Bai, Xue; Dai, Qilin; Zhang, Hui; Qin, Ruifei; Song, Hongwei
2011-06-01
Y 2O 3:Eu 3+ inverse opal films were fabricated by the self-assembly technique, which had a lattice parameter of ˜260 nm and a photonic stop band at 520 nm. Near the center of the photonic stop band, both the emission intensity and the spontaneous transition rate of 5D 1- 7F 1 transitions were modified. At the band gap edge, no obvious change was observed for the 5D 0- 7F J spontaneous transition rate, however, the emission intensity of 5D 0- 7F J ( J = 0, 1) was depressed in contrast to the 5D 0- 7F 2, which improved the color purity of the red emission.
True-time-delay photonic beamformer for an L-band phased array radar
NASA Astrophysics Data System (ADS)
Zmuda, Henry; Toughlian, Edward N.; Payson, Paul M.; Malowicki, John E.
1995-10-01
The problem of obtaining a true-time-delay photonic beamformer has recently been a topic of great interest. Many interesting and novel approaches to this problem have been studied. This paper examines the design, construction, and testing of a dynamic optical processor for the control of a 20-element phased array antenna operating at L-band (1.2-1.4 GHz). The approach taken here has several distinct advantages. The actual optical control is accomplished with a class of spatial light modulator known as a segmented mirror device (SMD). This allows for the possibility of controlling an extremely large number (tens of thousands) of antenna elements using integrated circuit technology. The SMD technology is driven by the HDTV and laser printer markets so ultimate cost reduction as well as technological improvements are expected. Optical splitting is efficiently accomplished using a diffractive optical element. This again has the potential for use in antenna array systems with a large number of radiating elements. The actual time delay is achieved using a single acousto-optic device for all the array elements. Acousto-optic device technologies offer sufficient delay as needed for a time steered array. The topological configuration is an optical heterodyne system, hence high, potentially millimeter wave center frequencies are possible by mixing two lasers of slightly differing frequencies. Finally, the entire system is spatially integrated into a 3D glass substrate. The integrated system provides the ruggedness needed in most applications and essentially eliminates the drift problems associated with free space optical systems. Though the system is presently being configured as a beamformer, it has the ability to operate as a general photonic signal processing element in an adaptive (reconfigurable) transversal frequency filter configuration. Such systems are widely applicable in jammer/noise canceling systems, broadband ISDN, and for spread spectrum secure communications
Ma, Chuan; Liu, Chunxiang; Yang, Pengcheng; Kang, Le
2009-01-01
Background The two closely related species of band-winged grasshoppers, Gastrimargus marmoratus and Oedaleus asiaticus, display significant differences in distribution, biological characteristics and habitat preferences. They are so similar to their respective congeneric species that it is difficult to differentiate them from other species within each genus. Hoppers of the two species have quite similar morphologies to that of Locusta migratoria, hence causing confusion in species identification. Thus we determined and compared the mitochondrial genomes of G. marmoratus and O. asiaticus to address these questions. Results The complete mitochondrial genomes of G. marmoratus and O. asiaticus are 15,924 bp and 16,259 bp in size, respectively, with O. asiaticus being the largest among all known mitochondrial genomes in Orthoptera. Both mitochondrial genomes contain a standard set of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and an A+T-rich region in the same order as those of the other analysed caeliferan species, but different from those of the ensiferan species by the rearrangement of trnD and trnK. The putative initiation codon for the cox1 gene in the two species is ATC. The presence of different sized tandem repeats in the A+T-rich region leads to size variation between their mitochondrial genomes. Except for nad2, nad4L, and nad6, most of the caeliferan mtDNA genes exhibit low levels of divergence. In phylogenetic analyses, the species from the suborder Caelifera form a monophyletic group, as is the case for the Ensifera. Furthermore, the two suborders cluster as sister groups, supporting the monophyly of Orthoptera. Conclusion The mitochondrial genomes of both G. marmoratus and O. asiaticus harbor the typical 37 genes and an A+T-rich region, exhibiting similar characters to those of other grasshopper species. Characterization of the two mitochondrial genomes has enriched our knowledge on mitochondrial genomes of Orthoptera. PMID
Technology Transfer Automated Retrieval System (TEKTRAN)
Presence of Gooseberry vein banding associated virus (GVBaV), a badnavirus in the family Caulimoviridae, is strongly correlated with gooseberry vein banding disease in Ribes spp. In this study, full-length genomic sequences of four GVBaV isolates from different hosts and geographic regions were det...
D'Aguanno, Giuseppe; Mattiucci, Nadia; Scalora, Michael; Bloemer, Mark J
2006-08-01
In the spectral region where the refractive index of the negative index material is approximately zero, at oblique incidence, the linear transmission of a finite structure composed of alternating layers of negative and positive index materials manifests the formation of a new type of band gap with exceptionally narrow band-edge resonances. In particular, for TM-polarized (transverse magnetic) incident waves, field values that can be achieved at the band edge may be much higher compared to field values achievable in standard photonic band-gap structures. We exploit the unique properties of these band-edge resonances for applications to nonlinear frequency conversion, second-harmonic generation, in particular. The simultaneous availability of high field localization and phase matching conditions may be exploited to achieve second-harmonic conversion efficiencies far better than those achievable in conventional photonic band-gap structures. Moreover, we study the role played by absorption within the negative index material, and find that the process remains efficient even for relatively high values of the absorption coefficient. PMID:17025558
Complete analysis of measurement-induced entanglement localization on a three-photon system
Gavenda, Miroslav; Filip, Radim; Nagali, Eleonora; Sciarrino, Fabio; Martini, Francesco De
2010-02-15
We discuss both theoretically and experimentally elementary two-photon polarization entanglement localization after break of entanglement caused by linear coupling of environmental photon with one of the system photons. The localization of entanglement is based on simple polarization measurement of the surrounding photon after the coupling. We demonstrate that nonzero entanglement can be localized back irrespectively to the distinguishability of coupled photons. Further, it can be increased by local single-copy polarization filters up to an amount violating Bell inequalities. The present technique allows restoration of entanglement in those cases, when the entanglement distillation produces no entanglement from the coupling.
NASA Astrophysics Data System (ADS)
Ustinov, A. B.; Drozdovskii, A. V.; Nikitin, A. A.; Kalinikos, B. A.
2015-12-01
The paper reports on development of tunable band-pass microwave filters for microwave photonic generators. The filters were fabricated with the use of epitaxial yttrium iron garnet films. Principle of operation of the filters was based on excitation, propagation, and reception of spin waves. In order to obtain narrow pass band, the filtering properties of excitation and reception antennas were exploited. The filters demonstrated insertion losses of 2-3 dB, bandwidth of 25-35 MHz, and tuning range of up to 1.5 GHz in the range 3-7 GHz.
NASA Astrophysics Data System (ADS)
Rakhymzhanov, A. M.; Gueddida, A.; Alonso-Redondo, E.; Utegulov, Z. N.; Perevoznik, D.; Kurselis, K.; Chichkov, B. N.; El Boudouti, E. H.; Djafari-Rouhani, B.; Fytas, G.
2016-05-01
The phononic band diagram of a periodic square structure fabricated by femtosecond laser pulse-induced two photon polymerization is recorded by Brillouin light scattering (BLS) at hypersonic (GHz) frequencies and computed by finite element method. The theoretical calculations along the two main symmetry directions quantitatively capture the band diagrams of the air- and liquid-filled structure and moreover represent the BLS intensities. The theory helps identify the observed modes, reveals the origin of the observed bandgaps at the Brillouin zone boundaries, and unravels direction dependent effective medium behavior.
Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo
2016-01-01
Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication. PMID:26912172
NASA Astrophysics Data System (ADS)
Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo
2016-02-01
Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication.
Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo
2016-01-01
Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication. PMID:26912172
Rahman, Mohammad Mahbubur; Marsal, Lluis F; Pallarès, Josep; Ferré-Borrull, Josep
2013-12-26
A distributed Bragg reflector based on nanoporous anodic alumina was fabricated using an innovative cyclic anodization voltage approach, which resulted in an in-depth modulation of the pore geometry and the refractive index. The effect of a pore-widening wet-etching step on the structure's photonic stop-band properties was studied. From transmittance measurements, it was shown that by changing the pore-widening time it is possible to modulate the photonic stop band in the range of visible to near infrared. With the help of a theoretical model, we were able to obtain information about the evolution with the pore widening of the material effective refractive indexes. This opens the possibility of obtaining several optoelectronic devices based on nanoporous anodic alumina. PMID:24283602
Wu, J.-N.; Huang, C.-H.; Cheng, S.-C.; Hsieh, W.-F.
2010-02-15
Spontaneous emission (SE) from a two-level atom in an anisotropic photonic crystal (PC) is investigated by the fractional calculus. Physical phenomena of the SE are studied analytically by solving the fractional kinetic equations of the SE. There is a dynamical discrepancy between the SE of anisotropic and isotropic PCs. We find that, contrary to the SE phenomenon of the isotropic PC, the SE near the band edge of an anisotropic PC shows no photon-atom bound state. It is consistent with the experimental results of Barth, Schuster, Gruber, and Cichos [Phys. Rev. Lett. 96, 243902 (2006)] that the anisotropic property of the system enhances the SE. We also study effects of dispersion curvatures on the changes of the photonic density of states and the appearance of the diffusion fields in the SE.
Dual-function photonic integrated circuit for frequency octo-tupling or single-side-band modulation.
Hasan, Mehedi; Maldonado-Basilio, Ramón; Hall, Trevor J
2015-06-01
A dual-function photonic integrated circuit for microwave photonic applications is proposed. The circuit consists of four linear electro-optic phase modulators connected optically in parallel within a generalized Mach-Zehnder interferometer architecture. The photonic circuit is arranged to have two separate output ports. A first port provides frequency up-conversion of a microwave signal from the electrical to the optical domain; equivalently single-side-band modulation. A second port provides tunable millimeter wave carriers by frequency octo-tupling of an appropriate amplitude RF carrier. The circuit exploits the intrinsic relative phases between the ports of multi-mode interference couplers to provide substantially all the static optical phases needed. The operation of the proposed dual-function photonic integrated circuit is verified by computer simulations. The performance of the frequency octo-tupling and up-conversion functions is analyzed in terms of the electrical signal to harmonic distortion ratio and the optical single side band to unwanted harmonics ratio, respectively. PMID:26030542
Zhang, Hai-Feng E-mail: lsb@nuaa.edu.cn; Liu, Shao-Bin E-mail: lsb@nuaa.edu.cn; Jiang, Yu-Chi
2014-09-15
In this paper, the tunable all-angle negative refraction and photonic band gaps (PBGs) in two types of two-dimensional (2D) plasma photonic crystals (PPCs) composed of homogeneous plasma and dielectric (GaAs) with square-like Archimedean lattices (ladybug and bathroom lattices) for TM wave are theoretically investigated based on a modified plane wave expansion method. The type-1 structure is dielectric rods immersed in the plasma background, and the complementary structure is named as type-2 PPCs. Theoretical simulations demonstrate that the both types of PPCs with square-like Archimedean lattices have some advantages in obtaining the higher cut-off frequency, the larger PBGs, more number of PBGs, and the relative bandwidths compared to the conventional square lattices as the filling factor or radius of inserted rods is same. The influences of plasma frequency and radius of inserted rod on the properties of PBGs for both types of PPCs also are discussed in detail. The calculated results show that PBGs can be manipulated by the parameters as mentioned above. The possibilities of all-angle negative refraction in such two types of PPCs at low bands also are discussed. Our calculations reveal that the all-angle negative phenomena can be observed in the first two TM bands, and the frequency range of all-angle negative refraction can be tuned by changing plasma frequency. Those properties can be used to design the optical switching and sensor.
NASA Astrophysics Data System (ADS)
Zhang, Hai-Feng; Liu, Shao-Bin; Jiang, Yu-Chi
2014-09-01
In this paper, the tunable all-angle negative refraction and photonic band gaps (PBGs) in two types of two-dimensional (2D) plasma photonic crystals (PPCs) composed of homogeneous plasma and dielectric (GaAs) with square-like Archimedean lattices (ladybug and bathroom lattices) for TM wave are theoretically investigated based on a modified plane wave expansion method. The type-1 structure is dielectric rods immersed in the plasma background, and the complementary structure is named as type-2 PPCs. Theoretical simulations demonstrate that the both types of PPCs with square-like Archimedean lattices have some advantages in obtaining the higher cut-off frequency, the larger PBGs, more number of PBGs, and the relative bandwidths compared to the conventional square lattices as the filling factor or radius of inserted rods is same. The influences of plasma frequency and radius of inserted rod on the properties of PBGs for both types of PPCs also are discussed in detail. The calculated results show that PBGs can be manipulated by the parameters as mentioned above. The possibilities of all-angle negative refraction in such two types of PPCs at low bands also are discussed. Our calculations reveal that the all-angle negative phenomena can be observed in the first two TM bands, and the frequency range of all-angle negative refraction can be tuned by changing plasma frequency. Those properties can be used to design the optical switching and sensor.
One-photon band gap engineering of borate glass doped with ZnO for photonics applications
Abdel-Baki, Manal; Abdel-Wahab, Fathy A.; El-Diasty, Fouad
2012-04-01
Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.
One-photon band gap engineering of borate glass doped with ZnO for photonics applications
NASA Astrophysics Data System (ADS)
Abdel-Baki, Manal; Abdel-Wahab, Fathy A.; El-Diasty, Fouad
2012-04-01
Lithium tungsten borate glass of the composition (0.56-x)B2O3-0.4Li2O-xZnO-0.04WO3 (0 ≤ x ≤ 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B2O3 by ZnO.
NASA Astrophysics Data System (ADS)
Martín-Doménech, R.; Manzano-Santamaría, J.; Muñoz Caro, G. M.; Cruz-Díaz, G. A.; Chen, Y.-J.; Herrero, V. J.; Tanarro, I.
2015-12-01
Context. Ice mantles that formed on top of dust grains are photoprocessed by the secondary ultraviolet (UV) field in cold and dense molecular clouds. UV photons induce photochemistry and desorption of ice molecules. Experimental simulations dedicated to ice analogs under astrophysically relevant conditions are needed to understand these processes. Aims: We present UV-irradiation experiments of a pure CO2 ice analog. Calibration of the quadrupole mass spectrometer allowed us to quantify the photodesorption of molecules to the gas phase. This information was added to the data provided by the Fourier transform infrared spectrometer on the solid phase to obtain a complete quantitative study of the UV photoprocessing of an ice analog. Methods: Experimental simulations were performed in an ultra-high vacuum chamber. Ice samples were deposited onto an infrared transparent window at 8K and were subsequently irradiated with a microwave-discharged hydrogen flow lamp. After irradiation, ice samples were warmed up until complete sublimation was attained. Results: Photolysis of CO2 molecules initiates a network of photon-induced chemical reactions leading to the formation of CO, CO3, O2, and O3. During irradiation, photon-induced desorption of CO and, to a lesser extent, O2 and CO2 took place through a process called indirect desorption induced by electronic transitions, with maximum photodesorption yields (Ypd) of ~1.2 × 10-2 molecules incident photon-1, ~9.3 × 10-4 molecules incident photon-1, and ~1.1 × 10-4 molecules incident photon-1, respectively. Conclusions: Calibration of mass spectrometers allows a direct quantification of photodesorption yields instead of the indirect values that were obtained from infrared spectra in most previous works. Supplementary information provided by infrared spectroscopy leads to a complete quantification, and therefore a better understanding, of the processes taking place in UV-irradiated ice mantles. Appendix A is available in
CW-pumped telecom band polarization entangled photon pair generation in a Sagnac interferometer
NASA Astrophysics Data System (ADS)
Li, Yan; Zhou, Zhi-Yuan; Ding, Dong-Sheng; Shi, Bao-Sen
2015-11-01
A polarization entangled photon pair source is widely used in many quantum information processing applications such as teleportation, quantum swapping, quantum computation and high precision quantum metrology. Here, we report on the generation of a continuous-wave pumped degenerated 1550 nm polarization entangled photon pair source at telecom wavelength using a type-II phase-matched periodically poled KTiOPO4 crystal in a Sagnac interferometer. Hong-Ou-Mandel-type interference measurement shows the photon bandwidth of 2.4 nm. High quality of entanglement is verified by various kinds of measurements, for example two-photon interference fringes, Bell inequality and quantum states tomography. The wavelength of photons can be tuned over a broad range by changing the temperature of crystal or pump power without losing the quality of entanglement. This source will be useful for building up long-distance quantum networks.
Complete N-Photon Greenberger-Horne-Zeilinger State Analysis Using Hyperentanglement
NASA Astrophysics Data System (ADS)
Wang, Chun; Zeng, Zhi; Li, Xihan
2016-03-01
We present a scheme for N-photon Greenberger-Horne-Zeilinger (GHZ) state analysis using hyperentanglement in polarization and time-bin degrees of freedom. The scheme only needs linear optics elements and single-photon detectors, which is feasible with current technology. The set of 2 N mutual orthogonal states can be unambiguously distinguished and the protocol is expected to find useful applications in quantum information processing.
Chaotic noise in superconducting microbridge 4-photon, x-band parametric amplifier
Andresen, J.E.; Christiansen, B.; Levinsen, M.T. )
1989-06-01
The anomalous noise rise observed in nearly all types of parametric amplifiers based on Josephson junctions has been an intriguing as well as annoying problem for many years. This phenomenon has been most spectacular in microbridge amplifiers. Here they present measurements on externally pumped single microbridge 4-photon unbiased amplifiers, where the slit with the bridge is used as a slotline resonantly coupled to the waveguide in an exceptionally simple coupling scheme. This scheme may be of interest in itself, particularly if the noise problem can be overcome, and in other connections. Up to 16 dB gain was obtained at the top of the waveguide. However, the noise rise was observed as usual. An analog computer study on a model including an input/output circuit was performed. The results are in very good agreement with the experiments. The amplification is heralded by a seemingly chaotic noise rise. This noise is then amplified linearly when gain occurs. Amplification is found to take place very close to where the supercurrent is completely suppressed by the pump. The cause of the noise rise has previously been interpreted as loss of phaselock. However, the power spectra of the time-derivative of the phase show this still to be locked in the region of positive gain. Furthermore, computations of the Lyapunov exponents show one to be positive in the region where gain occurs, reaching a maximum value at the parameters corresponding to maximum gain. They therefore conclude that chaotic noise is indeed present in Josephson junction parametric amplifiers where low-impedance devices such as microbridges with negligible capacitance are used as the active elements.
NASA Astrophysics Data System (ADS)
Zubov, A. S.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.
2011-10-01
Using the statistical and quantum diffusion approaches, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca,2n)254No, 206Pb(48Ca,2n)252No, and 204Hg(48Ca,2n)250Fm. By describing the relative intensities of E2 transitions between the rotational states, the entry spin distributions of residual nuclei, and the excitation functions for these reactions, the dependence of fission barriers of shell-stabilized nuclei on angular momentum is investigated.
NASA Astrophysics Data System (ADS)
Kim, Kwangmoo; Stroud, David
2014-03-01
We have calculated the photonic band structures of metallic inverse opals and of periodic linear chains of spherical pores in a metallic host, below a plasma frequency ωp. In both cases, we use a tight-binding approximation, assuming a Drude dielectric function for the metallic component, but without making the quasistatic approximation. The tight-binding modes are linear combinations of the single-cavity transverse magnetic (TM) modes. For the inverse-opal structures, the lowest modes are analogous to those constructed from the three degenerate atomic p-states in fcc crystals. For the linear chains, in the limit of small spheres compared to a wavelength, the results bear some qualitative resemblance to the dispersion relation for metal spheres in an insulating host, as calculated by Brongersma et al. [Phys. Rev. B 62, R16356 (2000)]. Because the electromagnetic fields of these modes decay exponentially in the metal, there are no radiative losses, in contrast to the case of arrays of metallic spheres in air. We suggest that this tight-binding approach to photonic band structures of such metallic inverse materials may be a useful approach for studying photonic crystals containing metallic components. This work was supported by KIAS, by NSF-MRSEC at OSU (DMR-0820414), and by DOE Grant No. DE-FG02-07ER46424. Computing resources were provided by OSC and by Abacus at KIAS.
Kim, Kwangmoo; Stroud, D
2013-08-26
We have calculated the photonic band structures of metallic inverse opals and of periodic linear chains of spherical pores in a metallic host, below a plasma frequency ωp. In both cases, we use a tight-binding approximation, assuming a Drude dielectric function for the metallic component, but without making the quasistatic approximation. The tight-binding modes are linear combinations of the single-cavity transverse magnetic (TM) modes. For the inverse-opal structures, the lowest modes are analogous to those constructed from the three degenerate atomic p-states in fcc crystals. For the linear chains, in the limit of small spheres compared to a wavelength, the results bear some qualitative resemblance to the dispersion relation for metal spheres in an insulating host, as calculated by Brongersma et al. [Phys. Rev. B 62, R16356 (2000)]. Because the electromagnetic fields of these modes decay exponentially in the metal, there are no radiative losses, in contrast to the case of arrays of metallic spheres in air. We suggest that this tight-binding approach to photonic band structures of such metallic inverse materials may be a useful approach for studying photonic crystals containing metallic components, even beyond the quasistatic approximation. PMID:24105532
NASA Astrophysics Data System (ADS)
Tang, Zheng-hua; Jiang, Zheng-Sheng; Chen, Tao; Lei, Da-Jun; Yan, Wen-Yan; Qiu, Feng; Huang, Jian-Quan; Deng, Hai-Ming; Yao, Min
2016-04-01
A novel phoxonic crystal using the piezoelectric (PMN-PT) and piezomagnetic (CoFe2O4) superlattices with three types of domains in a unit cell (PPSUC) is present, in which dual microwave photonic and phononic band gaps can be obtained simultaneously. Two categories of phononic band gaps, originating from both the Bragg scattering of acoustic waves in periodic structures at the Brillouin zone boundary and the electromagnetic wave-lattice vibration couplings near the Brillouin zone center, can be observed in the phononic band structures. The general characteristics of the microwave photonic band structures are similar to those of pure piezoelectric or piezomagnetic superlattices, with the major discrepancy being the appearance of nearly dispersionless branches within the microwave photonic band gaps, which show an extremely large group velocity delay. Thus, the properties may also be applied to compact acoustic-microwave devices.
NASA Astrophysics Data System (ADS)
Amri, R.; Sahel, S.; Manaa, C.; Bouaziz, L.; Gamra, D.; Lejeune, M.; Clin, M.; Zellama, K.; Bouchriha, H.
2016-08-01
Hybrid One-dimensional photonic crystal coated from a mixture of an organic compound (HMDSO) and oxygen (O2) is elaborated by PECVD technique. The originality of the method consists in obtaining layers of different permittivity with the same gas mixture, but with different flow. The change in flow is optimized to obtain organic/inorganic layers of good quality with high and low refractive index of 2.1 and 1.4 corresponding respectively to HMDSO and SiO2 materials as assigned by IR measurement. Evidence of the photonic band gap is obtained by measuring the transmissions and reflections spectra which show that it appears only after 13 periods with a width of 325 nm corresponding to energy 3.8 eV. We have also introduced a defect in this photonic structure by changing the thickness of central layer, and observed the presence of a frequency mode corresponding to this defect. Our results are interpreted by using a theoretical model based on transfer matrix wich well reproduced the experimental data.
Femtosecond Pulse Characterization as Applied to One-Dimensional Photonic Band Edge Structures
NASA Technical Reports Server (NTRS)
Fork, Richard L.; Gamble, Lisa J.; Diffey, William M.
1999-01-01
The ability to control the group velocity and phase of an optical pulse is important to many current active areas of research. Electronically addressable one-dimensional photonic crystals are an attractive candidate to achieve this control. This report details work done toward the characterization of photonic crystals and improvement of the characterization technique. As part of the work, the spectral dependence of the group delay imparted by a GaAs/AlAs photonic crystal was characterized. Also, a first generation an electrically addressable photonic crystal was tested for the ability to electronically control the group delay. The measurement technique, using 100 femtosecond continuum pulses was improved to yield high spectral resolution (1.7 nanometers) and concurrently with high temporal resolution (tens of femtoseconds). Conclusions and recommendations based upon the work done are also presented.