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Accepted papers to appear in an upcoming issue

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Error-compensation measurements on polarization qubits

Guoyong Xiang, Zhibo Hou, Huangjun Zhu, Chuanfeng Li, and Guang-can Guo

Doc ID: 262980 Received 14 Apr 2016; Accepted 27 Apr 2016; Posted 29 Apr 2016  View: PDF

Abstract: Systematic errors are inevitable in most measurements performed in real life because of imperfect measurement devices. Reducing systematic errors is crucial to ensuring the accuracy and reliability of measurement results. To this end, delicate error-compensation designs are often necessary in addition to device calibration to reduce the dependence of the systematic error on the imperfection of the devices. The art of error-compensation designs is well appreciated in nuclear magnetic resonance systems by using composite pulses. In contrast, there are few works on reducing systematic errors in quantum optical systems. Here we propose an error-compensation design applicable to reducing the systematic error in projective measurements on ensembles of both single and multiqubit systems. This design can significantly decrease the systematic error due to dominant error sources in typical optical experiments. In particular, it can reduce the systematic error to the second order of the phase errors of both the half-wave plate (HWP) and the quarter-wave plate (QWP) as well as the angle error of the HWP. Its power in reducing the systematic error was verified experimentally on qubit state tomography and numerically on two-qubit state tomography. Our study may find applications in high-precision tasks in polarization optics and quantum optics.

Two-dimensional double-quantum spectroscopy: peak shapes as a sensitive probe of carrier interactions in quantum wells

Jeffrey Davis and Jonathan Tollerud

Doc ID: 258798 Received 03 Feb 2016; Accepted 26 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We identify carrier scattering at densities below which it has previously been observed in semiconductor quantum wells. These effects are evident in the peakshapes of 2D double-quantum spectra, which change as a function of excitation density. At high excitation densities ($\geq10^{9}$\,carriers/,cm$^{-2}$) we observe untilted peaks similar to those reported in previous experiments. At low excitation densities (\textless$10^{8}$\,carriers\,cm$^{-2}$) we observe narrower, tilted peaks.Using a simple simulation, we show that tilted peak-shapes are expected in double-quantum spectra when inhomogeneous broadening is much larger than homogeneous broadening, and that fast pure-decoherence of the double-quantum coherence can obscure this peak tilt. These results show that carrier interactions are important at lower densities than previously expected, and that the `natural' double-quantum peakshapes are hidden by carrier interactions at the excitation densities typically used. Furthermore, these results demonstrate that analysis of 2D peak-shapes in double-quantum spectroscopy provides an incisive tool for identifying interactions at low excitation density.

Structure-property relations in individual carbon nanotubes

Kaihui Liu, Fengrui Yao, Jingyi Tang, and Feng Wang

Doc ID: 259219 Received 11 Feb 2016; Accepted 26 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: After more than a quarter century’s intense research and exploration for its distinctive physical properties and potential applications, carbon nanotubes remains an active research field with many surprises and opportunities. Recent advances in nano-optics provide a powerful tool to optically characterize carbon nanotubes with defined chiral index at single-nanotube level. Here we review our recent effort along this direction, including (1) combing transmission electron microscopy and single-nanotube optical spectroscopy to establish the atlas for carbon nanotube optical transitions and (2) developing a high-contrast polarization microscope for real-time optical imaging and in-situ spectroscopy of individual nanotubes in devices. We will also discuss the importance of such characterizations for controlled nanotube growth and for understanding chirality-dependent device behaviors.

Dynamic vibronic coupling in InGaAs quantum dots [Invited]

A. Mark Fox, Alistair Brash, Luis Martins, Andreas Barth, Feng Liu, John Quilter, Martin Glässl, Vollrath Martin Axt, Andrew Ramsay, and Maurice Skolnick

Doc ID: 259423 Received 16 Feb 2016; Accepted 26 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: The electron-phonon coupling in self-assembled InGaAs quantum dots is relatively weak at low light intensities,which means that the zero-phonon line in emission is strong compared to the phonon sideband.However, the coupling to acoustic phonons can be dynamically enhanced in the presence of an intenseoptical pulse tuned within the phonon sideband. Recent experiments have shown that this dynamic vibroniccoupling can enable population inversion to be achieved when pumping with a blue-shifted laserand for rapid de-excitation of an inverted state with red detuning. In this paper we confirm the incoherentnature of the phonon-assisted pumping process and explore the temperature dependence of the mechanism.We also show that a combination of blue- and red-shifted pulses can create and destroy an excitonwithin a timescale ∼ 20 ps determined by the pulse duration and ultimately limited by the phonon thermalisationtime.

Cross Phase Modulation Enhancement Via a Resonating Cavity: Semiclassical Description

Julian Martinez and John Howell

Doc ID: 259427 Received 19 Feb 2016; Accepted 26 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We evaluate the advantages of performing cross phase modulation (XPM) on a very-far-off-resonance atomic system. We consider a ladder system with a weak (few-photon level) control coherent field imparting a conditional nonlinear phase shift on a probe beam. We find that by coupling to an optical resonator the optimal XPM is enhanced proportional to the finesse of the resonator by a factor of $F/4\pi$. We present a semi-classical description of the system and show that the phenomenon is optimal in the self-defined condition of off-resonance-effective-cooperativity equal to one.

Plamon Optical Trapping Using Silicon Nitride Trench Waveguides

Qiancheng Zhao, Caner Guclu, Yuewang Huang, Filippo Capolino, Regina Ragan, and Ozdal Boyraz

Doc ID: 259769 Received 22 Feb 2016; Accepted 25 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We demonstrate optical trapping using a silicon nitride (Si₃N₄) trench waveguide on which bowtie plasmonic nanoantennas are employed for enhancing optical forces. The electric field tailing away from the waveguide is transformed and then enhanced by the plasmonic nanoantennas deposited on the waveguide surface. We show that, with gold bowtie nanoantennas, the waveguide system exhibits outstanding trapping capability on a 10 nm radius polystyrene nanoparticle, due to a 60-fold electric field enhancement in proximity of the nanoantenna gap. This enhancement causes a boost of the optical trapping force by three orders of magnitude. The gradient force in vertical direction is also calculated analytically by using a dipole approximation of a scattering polystyrene nanosphere, and the analytical solution well matches full-wave simulations. Mode polarization effects are discussed in this paper as a way to switch trapping. These investigations indicate that the patterned Si₃N₄ trench waveguide is suitable for optical trapping and nanoparticle sensing applications.

General theoretical treatment of spectral modulation light labeling spectroscopy

Scott Domingue and Randy Bartels

Doc ID: 259954 Received 24 Feb 2016; Accepted 25 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We theoretically derive the analytic relationship between experimental parameters and the measured incident (or illumination) optical power spectrum for a new form of spectroscopy, entitled light labeling spectroscopy. The light labeling signals are shown to arise from the interference between fields diffracted from a grating with time varying ruling density. A Gaussian model is used to illustrate the bounds of the method for recovering power spectra without artificial spectral apodization. Finally, several example systems are tabulated to give numerical insight into the possible system performances across a range of wavelength regions.

Theoretical analysis of high power longitudinally diode-pumped self-frequency-doubling Nd:YCOB laser

ZONG Nan, Dai shibo, Feng Yang, SHEN Yu, zhimin wang, Fengfeng Zhang, Da Cui, Qinjun Peng, and Zuyan Xu

Doc ID: 260909 Received 10 Mar 2016; Accepted 25 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We report a theoretical analysis of laser-diode pumped self-frequency doubling (SFD) Nd:Ca₄YO(BO₃)₃(Nd:YCOB) laser for high output power. A SFD model is presented by combining laser rate equation and second harmonic generation coupled wave equations inside the same laser crystal. In this SFD model, the continuous wave end-pumped space-dependence Gaussian beam profile, the variation of the pump beam waist, the fundamental wave depletion and the thermally induced diffractive losses are taken into account. In order to investigate the dependence of SFD output power on the Nd3+ doping concentration, we implement the measurement of the absorption spectra for different Nd3+ doping Nd:YCOB samples. The comparison of plane wave approximation, Gaussian beam model with and without the thermally induced diffractive losses are presented. Then, we focuses on the optimization of high power SFD Nd:YCOB laser, including the optimum pump beam waist, the optimum Nd3+ doping concentration and the optimum Nd:YCOB crystal length.

Picosecond gain recovery in SOA and its application for 40Gb/s regenerative format conversion from NRZ-DPSK to RZ-OOK

Xinliang Zhang, Tong Cao, Liao Chen, and Yu Yu

Doc ID: 259117 Received 08 Feb 2016; Accepted 25 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We propose a scheme to realize picosecond gain recovery in a typical quantum well semiconductor optical amplifier (QW-SOA) using the pump signal with amplitude dips. In the scheme, the gain recovery is determined by the carrier density depletion and carrier temperature heating, which are both ultrafast processes. The picosecond gain recovery is numerically verified by a completed model combining QW band structure calculation with SOA’s carrier density and temperature rate equations. In practice, the pump signal with amplitude dips can be partly characterized by the NRZ-DPSK signal generated by a Mach-Zehnder modulator. Therefore, we experimentally demonstrate the 40 Gb/s wavelength-converting and regenerative format conversion from NRZ-DPSK to RZ-OOK, which may be a key functionality to connect different kinds of modulation formats at gateway nodes between long-haul backbone networks and metro area networks.

Quantum interference induced photon localisation and delocalisation in coupled cavities

Srinivasan Sivakumar and Nilakantha Meher

Doc ID: 257110 Received 08 Jan 2016; Accepted 25 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: We study photon localisation and delocalisation in a system of two nonlinear cavities with intensity-dependent coupling. It is shown that complete localisation or delocalisation is possible for proper choices of the strengths of nonlinearity, detuning and inter-cavity coupling. Role of the relative phase in the initial superposition in attaining localisation and delocalisation is discussed. Effects of dissipation and decoherence are considered and the role of quantum interference in mitigating these effects is explored.

Thermalization and Bose-Einstein condensation of aphoton gas in a multimode hybrid atom-membraneoptomechanical microcavity

M H Naderi and Marjan Fani

Doc ID: 258687 Received 03 Feb 2016; Accepted 23 Apr 2016; Posted 28 Apr 2016  View: PDF

Abstract: In this paper, we propose theoretically an optomechanical scheme to thermalize a two-dimensional photongas in a hybrid optomechanical microcavity composed of a two-level atomic ensemble and a membraneoscillator enclosed in an optical cavity. The thermalization process is based on a phonon-inducedasymmetry between the emission and the absorption rates of the atoms. We show that whenever thisasymmetry obeys the detailed balance condition and if the photon lifetime is high enough, the steadystatephoton number distribution matches the Bose-Einstein distribution. Furthermore, in order to studythe effect of the optomechanical coupling on the Bose-Einstein condensation of photons, we calculatethe cricital photon number as a function of the temperature. We find that the optomechanically-inducednonlinearity leads to the increase of the critical photon number which can be controlled by tuning theoptomechanical parameters.

Electromagnetically induced absorption aiding laser cooling of 171Yb

John Mc Ferran

Doc ID: 261826 Received 25 Mar 2016; Accepted 23 Apr 2016; Posted 27 Apr 2016  View: PDF

Abstract: We observe electromagnetically induced absorption in π driven, degenerate two-level transitions where F'-F=0,+1. The signal is observed through saturated absorption spectroscopy of the (6s^{2}) ^{1}S_{0} - (6s6p) ^{3}P_{1} transition in ^{171}Yb, where the nuclear spin I=1/2. The enhanced absorption signal is used to generate a dispersive curve for 556 nm laser frequency stabilisation and the stabilised light cools ^{171}Yb atoms in a two-stage magneto-optical trap, achieving temperatures of 20 μK. The Doppler-free spectroscopy scheme is further used to measure isotopic frequency shifts and hyperfine separations for the intercombination line in ytterbium

The Quasi-Rotating Frame: accurate line shape determination with increased efficiency in non-collinear 2D optical spectroscopy

Michael Fayer, Patrick Kramer, Chiara Giammanco, Amr Tamimi, David Hoffman, and Kathleen Sokolowsky

Doc ID: 260334 Received 01 Mar 2016; Accepted 21 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: Multidimensional spectroscopies correlate the oscillation frequencies of an atomic or molecular resonance during at least two different time periods. For two-dimensional (2D) optical spectroscopy, oscillations in the first coherence period are sampled in the time domain point-by-point. We present a general method for accelerating this often lengthy task, the Quasi-Rotating Frame (QRF), through heterodyne detection of the nonlinear signal pulse with a systematic variably delayed local oscillator pulse in a non-collinear (box-CARS) geometry four wave mixing experiment. 2D infrared (2D IR) vibrational echo experiments are conducted to demonstrate the QRF technique, and the results are compared to data obtained in the stationary frame. We describe straightforward techniques to configure QRF detection, prevent experimental artifacts, appropriately calibrate the rotating frame frequencies, and process the resulting data such that accurate liquid structural dynamics may be extracted from a series of waiting-time-dependent 2D spectral line shapes.

Compound Guided Waves That Mix Characteristics of Surface-Plasmon-Polariton, Tamm, Dyakonov--Tamm, and Uller--Zenneck Waves

Francesco Chiadini, Vincenzo Fiumara, Antonio Scaglione, and Akhlesh Lakhtakia

Doc ID: 261349 Received 16 Mar 2016; Accepted 21 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: Solutions of the boundary-value problem for electromagnetic waves guided by a layer of a homogeneous and isotropic (metal or dielectric) material sandwiched between a structurally chiral material (SCM) and a periodically multi-layered isotropic dielectric (PMLID) material were numerically obtained and analyzed. If the sandwiched layer is sufficiently thick, the two bimaterial interfaces decouple from each other, and each interface may guide one or more electromagnetic surface waves (ESWs) by itself. Depending on the constitution of the two materials that partner to form an interface, the ESWs can be classified as surface-plasmon-polarition (SPP) waves, Tamm waves, Dyakonov-Tamm waves, or Uller-Zenneck waves. When the sandwiched layer is sufficiently thin, the ESWs for single bimaterial interfaces coalesce to form compound guided waves (CGWs). The phase speeds, propagation distances, and spatial profiles of the electromagnetic fields of CGWs are different from those of the ESWs. The energy of a CGW is distributed in both the SCM and the PMLID material, if the sandwiched layer is sufficiently thin. Some CGWs require the sandwiched layer to have a minimum thickness. Indeed, the coupling between the two faces of the sandwiched layer is affected by the ratio of the thickness of the sandwiched layer to the skin depth in that material and the rates at which the fields of the ESWs guided individually by the two interfaces decay away from their respective guiding interfaces.

Absolute Te2 reference for barium ion at 455.4 nm

Manas Mukherjee, Tarun Dutta, and Debashis De Munshi

Doc ID: 257861 Received 22 Jan 2016; Accepted 20 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: Precision atomic spectroscopy is presently the work horse in quantum information technology, metrology, trace analysis and even for fundamental tests in Physics. Stable lasers are inherent part of precision spectroscopy which in turn requires absolute wavelength markers suitably placed corresponding to the atomic species being probed. Here we present, newlines of tellurium (Te2) which allows locking of external cavity diode laser (ECDL) for precision spectroscopy of singly charged barium ions. In addition, we have developed an ECDL with over 100 GHz mod-hop-free tuning range using commercially available diode from Nichia. These two developments allow nearly drift-free operation of a barium ion trap setup with one single reference cell thereby reducing the complexity of the experiment.

Transformation of liquid water to ice VII during propagation of picosecond laser pulses: effect of wavelength and polarization

Prem Kiran Paturi and RAKESH VADDAPALLY

Doc ID: 258243 Received 25 Jan 2016; Accepted 20 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: The dependence on input wavelength and polarization of the formation of ice VII phase of liquid water during propagation of 30 ps laser pulses using stimulated Raman scattering (SRS) is studied. Raman (Stokes and anti-Stokes) shifts corresponding to both liquid water and ice VII peaks are observed with 532 nm and 1064 nm excitation, whereas with 355 nm Raman shifts due to liquid water alone are observed. An interesting energy transfer between anti-Stokes modes of ice VII and that of water is observed at 1064 nm excitation. Higher Stokes percentage of conversion efficiency with circular polarization for 532 nm and 355nm and higher anti-Stokes with linear polarization for 532 nm and 1064 nm are observed. SRS signals in the forward and backward directions with 532 nm excitation has shown that the Raman shifts confirm the generation of GPa pressures in liquid water around the focal volume. The evolution of Raman shifts of ice VII phase with input polarization studied at 532 nm excitation wavelengths indicated the presence of pressures in the range of 8.7-10.7 GPa in forward and 8.7-11.5 GPa in the backward directions. The longitudinal imaging of the self-emission due to filamentation of ps pulses propagating through liquid water indicated the localization of energy around the focal volume leading to cavitation supporting the presence of higher plasma pressures.

Floquet-Bloch Analysis of Analytically Solvable Hill Equations with Continuous Potentials

Gregory Morozov, Donald Sprung, Stuart Caffrey, and Darryl MacBeath

Doc ID: 259463 Received 17 Feb 2016; Accepted 20 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: Exact analytical solutions of two Hill's equations which have continuously differentiable coefficients, are obtained in terms of the Floquet-Bloch fundamental system. New features of the band structures of those equations are reported and investigated.

Mesoscopic effects of a particle on quantum correlations of Raman photon pairs

Raymond Ooi and Kam Chan Hin Chan Hin

Doc ID: 255095 Received 11 Dec 2015; Accepted 20 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: Quantum correlations of photon pairs emitted by a mesoscopicparticle (microsphere) composed of a large number of quantumparticles in double Raman scheme is studied. Quantum Langevinformalism with noise operators is used to compute the nonclassicalcorrelations between the Stokes and anti-Stokes photons,particularly the Glauber's second order cross- andself-correlations functions. The theory is developed in arealistic manner, i.e. including the focusing effect of theparticle on the pump and control laser fields as well as lineardispersion of the microsphere. The results enable us to analyzehow the photon correlations are affected by the size of themicrosphere, the morphology resonance, the detection directionrelative to the lasers, as well as the detuning and the strengthof the lasers.

Topological polaritons with squeezed photons

xiao Guo, Zaijun Wang, Zimeng Chi, Qiang Zheng, and Xiaobin Ren

Doc ID: 255678 Received 17 Dec 2015; Accepted 19 Apr 2016; Posted 22 Apr 2016  View: PDF

Abstract: In this paper, we demonstrate that the topological polaritonic states of a two-dimensional coupled matter-light system can be optically controlled. By introducing a squeezed light field, we generalized the model of topological polaritons, where the matter-light coupling constant winds in momentum space leading to the non-trivial topology. The bulk excitation spectrum, polariton wavefunction, topological invariant, and edge mode spectrum are calculated. It is found that mixing the excitons with non-squeezing photons will result in a polaritonic state of time-reversal-symmetry-breaking quantum-spin-Hall-like. However, the quantum-Hall-like state arises when the photonic part of polaritons is squeezed. Driven by the varying degrees of squeezing, there is a topological phase transition with the closing of the bulk excitation gap. Across the phase transition, the direction of edge mode propagation is reversed, which is demonstrated by an edge mode simulation. Such a feature may provide an opportunity for realizing the one-way edge channels with adjustable directionality.

Modulation instability in oppositely nonlinear directed coupler with saturable nonlinearities and higher-order effects

Wesley Cardoso, Ardiley Avelar, and Erivelton Alves

Doc ID: 256635 Received 30 Dec 2015; Accepted 18 Apr 2016; Posted 19 Apr 2016  View: PDF

Abstract: We investigate the influence of a saturable nonlinearity on the modulation instability in oppositely di- rected coupler in the presence of high-order effect and obtain significant changes in the bands of insta- bility. For both channels influenced by either self-steepening effect or self-steepening effect but opposite in sign no change in instability gain is obtained. Also, there is reflection symmetry (asymmetry) to the gain at zero perturbation frequency when the values of the Raman coefficients in each directional coupler are equal and with same (opposite) sign. Finally, we show that an efficient control of the modulation instability can be realized by adjusting self-steepening effect and intrapulse Raman scattering, even in the presence of a saturable nonlinearity.

Frequency tunable perfect absorber in visible and near-infrared regime based on VO2 phase transition using planar layered thin films

Jiran Liang, Luhui Hou, and Jingpeng Li

Doc ID: 259523 Received 16 Feb 2016; Accepted 16 Apr 2016; Posted 19 Apr 2016  View: PDF

Abstract: We show a frequency tunable perfect absorber in visible and near-infrared regime based on VO2 phase transition with the wide tuning capability typical of asymmetric Fabry-Perot (FP) cavities, comprising only an un-patterned, ultra-thin (~ /15) film of vanadium dioxide (VO2) deposited on a metal reflecting substrate (VOM). VO2 undergoes a structural transition from an insulating phase (i-VO2) to a metallic phase (m-VO2) at 68℃. Perfect absorption wavelength can be dynamic tuned over a wide wavelength range over 175 nm (from 905 nm to 730 nm in measured spectrum) in visible and near-infrared regime by controlling the temperature. More importantly, its absorption peaks become even stronger during the process of temperature increasing (from the 97.6% at the 905nm to 99.4% at the 730nm). The frequency tunable absorption peaks were explained with that both index of the i-VO2 and m-VO2 are very close to the maximum absorption point in n-k parameter space and the excitation of planar SPPs.

Dispersion effects on the nonlinear foci of femtosecond pulse

Wenbin Lin and Cunliang Ma

Doc ID: 257988 Received 21 Jan 2016; Accepted 14 Apr 2016; Posted 15 Apr 2016  View: PDF

Abstract: The nonlinear foci is an important parameter for the filamentation phenomena since it denotes the beginning of the filamentation stage when the initial power is near or larger than the filamentation threshold $P_{TH}$ ( [Optics Letters 19, 862 (1994)] and [Physical Review A 78, 033826 (2008)]). We combine the pulse's dispersion length with the Dawes and Marburger's formula, and achieve a new formula which can predict the nonlinear foci very well regardless of the dispersion being important or not. We also find there exists a threshold $P_{ML}$ for the initial peak power, with which the nonlinear foci has a maximum length due to the competition between Kerr self-focusing and the dispersion.

Temporal Waveguides for Optical Pulses

Brent Plansinis, William Donaldson, and Govind Agrawal

Doc ID: 259024 Received 08 Feb 2016; Accepted 13 Apr 2016; Posted 15 Apr 2016  View: PDF

Abstract: Temporal total internal reflection (TIR), in analogy to the conventional TIR of an optical beam at a dielectric interface, is the total reflection of an optical pulse inside a dispersive medium at a temporal boundary across which the refractive index changes. A pair of such boundaries separated in time should act as the temporal analog of planar dielectric waveguides. We analytically and numerically study the propagation of optical pulses inside such a temporal waveguide and show that a pulse is confined to the temporal region between the two boundaries when the TIR condition is satisfied. In contrast with the spatial case, the confinement can occur even when the central region has a lower refractive index. We also analyze the modes of a temporal waveguide and show how a single-mode temporal waveguide can be created in practice.

Comparative study of optical levitation traps: focused-Bessel beam vs Gaussian beams

Yareni Aguilar, Alejandro Arzola, and Karen Volke-Sepulveda

Doc ID: 255708 Received 14 Dec 2015; Accepted 13 Apr 2016; Posted 13 Apr 2016  View: PDF

Abstract: In optical levitation traps, a light beam propagating upward is focused with a relatively low numerical aperture (NA), producing a large scattering force along the propagation direction which is balanced by the effective weight of a particle. Here we present a detailed study of four levitation traps obtained when the trapping beam is a fundamental Gaussian mode focused with different NA, in comparison with a levitation trap obtained with a Bessel beam focused through a lens with NA=0.40. A theoretical analysis for the optical field and trapping forces along the lateral and axial directions is presented for all the traps, and contrasted with experimental results. We show that the focusedBessel trap (FBT) offers highly superior capabilities formanipulation of individual glass beads in three dimensions, along with other advantages in comparison with standard optical tweezers, such as an extended working distance, larger field of view and lower spherical aberration.

Design Considerations for a Dynamic Metamaterial Aperture for Computational Imaging at Microwave Frequencies

Timothy Sleasman, Michael Boyarsky, Mohammadreza Imani, Jonah Gollub, and David Smith

Doc ID: 256590 Received 04 Jan 2016; Accepted 13 Apr 2016; Posted 15 Apr 2016  View: PDF

Abstract: We investigate the imaging capabilities of a one-dimensional, dynamic, metamaterial aperture that operates at the base of K-band microwave frequencies (17.5-21.1 GHz). The dynamic aperture consists of a microstrip transmission line with an array of radiating, complementary, subwavelength metamaterial irises patterned into the upper conductor. Diodes integrated into the metamaterial resonators provide voltage-controlled switching of the resonant metamaterial elements between radiating and non-radiating states. Applying a series of \emph{on}/\emph{off} patterns to the metamaterial resonators produces a series of distinct radiation patterns that sequentially illuminate a scene. The backscattered signal contains encoded scene information over a set of measurements that can be post-processed to reconstruct an image. We present a series of design considerations for the dynamic aperture, as well as a series of experimental studies performed using a dynamic aperture prototype. High-fidelity, real-time, diffraction-limited imaging using the prototype is demonstrated. The dynamic aperture suggests a path to fast and reliable imaging with low-cost and versatile hardware, for a variety of applications including security screening, biomedical diagnostics, and through-wall imaging.

End-fire coupling efficiencies of surface plasmons for silver, gold, and plasmonic nitride compounds

Caitlin Fisher, Lindsay Botten, Chris Poulton, Ross McPhedran, and C. Martijn de Sterke

Doc ID: 256398 Received 11 Jan 2016; Accepted 12 Apr 2016; Posted 12 Apr 2016  View: PDF

Abstract: We present a semi-analytical study exploring the end-fire coupling of a freespace incident beam into a surface plasmon propagating along the interfaceof a dielectric and a lossy plasmonic material. Using a projection method, which calculates the surface plasmon coupling efficiencies for this configuration, we explain in detail how the challenges of including loss, and thus having complex permittivities, have been overcome. A comparison is made of the coupling efficiencies of four plasmonic materials: Ag, Au, TiN and ZrN. We show that TiN out-performs the other three for wavelengths between 0.5 μm and 2.0 μm, but that all four are capable of providing end-fire coupling efficiencies above 87%.

Attosecond optics and technology: Progress to-date and future prospects (Centennial)

Zenghu Chang, Paul Corkum, and Stephen Leone

Doc ID: 256713 Received 04 Jan 2016; Accepted 11 Apr 2016; Posted 12 Apr 2016  View: PDF

Abstract: The milestones of attosecond optics research in the last fifteen years are briefly reviewed, and the latest trends in applications in gaseous and condensed matter are introduced. An outlook on future development of attosecond soft x-ray sources and their application is provided.

Dye embedded and nanopatterned hyperbolic metamaterials for spontaneous emission rate enhancement

Koduru Hari Krishna, Sreekanth Kandammathe Valiyaveedu, and Giuseppe Strangi

Doc ID: 256526 Received 04 Jan 2016; Accepted 11 Apr 2016; Posted 11 Apr 2016  View: PDF

Abstract: Enhancement of spontaneous emission is a dynamic and challenging fundamental quantum phenomenon in optics and in nutshell it opens new avenues for spectrum of futuristic applications. Here, we experimentally demonstrate a large improvement in spontaneous emission rate enhancement of fluorescent molecules using dye embedded and grating coupled (nanopatterned) multi-layered metal-dielectric hyperbolic metamaterials. About 35-fold spontaneous emission decay rate enhancement of dye molecules is obtained using a two-dimensional (2D) silver diffraction grating coupled with dye embedded hyperbolic metamaterial. Further, we numerically and experimentally demonstrate a comparative study on modification of spontaneous emission of fluorescent dye molecules placed in the vicinity of HMM structure and dye molecules embedded HMM structure. The obtained results pave the way of finding fruitful applications including single photon sources.

Impact of high-order-mode loss on high-power fiber amplifiers

shaofeng Guo, Liangjin Huang, Lingchao Kong, Jinyong Leng, Pu Zhou, and Xiang'ai Cheng

Doc ID: 256108 Received 22 Dec 2015; Accepted 10 Apr 2016; Posted 11 Apr 2016  View: PDF

Abstract: In this paper, we demonstrate a model accounting for the impact of the loss of high-order-mode (HOM) on the performances of high-power fiber amplifiers with various parameters such as pump wavelength, pumping direction and fiber length. The results show that uniform gain distribution along the fiber length in the counter-pumping scheme benefits the HOM suppression compared with the co-pumping case. Besides, the results indicate that the total HOM loss should be greater than the total HOM gain over the propagation distance in order to achieve effective single-mode (ESM) operation. Furthermore, the loss of HOM should exceed the maximum achieved local gain of the HOM for not only suppressing the HOM but also achieving high efficiency and low cladding light. The results will provide guidelines on designing large-mode-area fiber aiming at ESM output based on differential loss between the HOMs and the fundamental mode.

Towards room-temperature superfluidity of exciton polaritons in an optical microcavity with an embedded MoS2 monolayer

German Kolmakov, Leonid Pomirchi, and Roman Kezerashvili

Doc ID: 259153 Received 12 Feb 2016; Accepted 09 Apr 2016; Posted 11 Apr 2016  View: PDF

Abstract: By considering driven diffusive dynamics of exciton polaritons in an optical microcavity with an embedded molybdenum disulfide monolayer, we determine experimentally relevant range of parameters at which room-temperature superfuidity can be observed. It is shown that the superfluid transitions occurs in a trapped polariton gas at laser pumping power P > 600 mW and and trapping potential strength k > 50 eV/cm2. We also propose a simple analytic model that provides a useful estimate for the polariton gas density, which enables one to determine the conditions for observation of room temperature polariton superfluidity.

Bulk sensing using a long-range surface-plasmon triple-output Mach-Zehnder interferometer

Hui Fan and Pierre Berini

Doc ID: 258602 Received 01 Feb 2016; Accepted 08 Apr 2016; Posted 08 Apr 2016  View: PDF

Abstract: A triple-output Mach-Zehnder interferometric sensor operating with long-range surface plasmon-polaritons at free-space wavelengths near 1310 nm was constructed by etching a microfluidic channel through the top cladding (Cytop) of one arm of the interferometer to expose the Au stripe embedded therein. Optical bulk (refractometric) sensing was conducted by sequentially flowing sample solutions with different refractive indices through the microfluidic channel and measuring the optical powers of the three outputs, which responded sinusoidally and were separated by ~2π/3 rad as expected in theory. Three detection schemes are analyzed and compared, demonstrating that the device benefits from a 3× larger dynamic range and the ability to suppress common perturbations relative to its single-output counterpart, thus improving the detection limit. The device is promising for application to biosensing.

Dicke Superradiance in Solids

Junichiro Kono, Kankan Cong, Qi Zhang, Yongrui Wang, Gary Noe, and Alexy Beyanin

Doc ID: 259437 Received 18 Feb 2016; Accepted 07 Apr 2016; Posted 08 Apr 2016  View: PDF

Abstract: Recent advances in optical studies of condensed matter systems have led to the emergence of a variety of phenomena that have conventionally been studied in the realm of quantum optics. These studies have not only deepened our understanding of light-matter interactions but also introduced aspects of many-body correlations inherent in optical processes in condensed matter systems. This article is concerned with the phenomenon of superradiance (SR), a profound quantum optical process originally predicted by Dicke in 1954. The basic concept of SR applies to a general $N$-body system where constituent oscillating dipoles couple together through interaction with a common light field and accelerate the radiative decay of the whole system. Hence, the term SR ubiquitously appears in order to describe radiative coupling of an arbitrary number of oscillators in many situations in modern science of both classical and quantum description. In the most fascinating manifestation of SR, known as superfluorescence (SF), an incoherently prepared system of $N$ inverted atoms spontaneously develops macroscopic coherence from vacuum fluctuations and produces a delayed pulse of coherent light whose peak intensity $\propto N^2$. Such SF pulses have been observed in atomic and molecular gases, and their intriguing quantum nature has been unambiguously demonstrated. In this review, we focus on the rapidly developing field of research on SR phenomena in solids, where not only photon-mediated coupling (as in atoms) but also strong Coulomb interactions and ultrafast scattering processes exist. We describe SR and SF in molecular centers in solids, molecular aggregates and crystals, quantum dots, and quantum wells. In particular, we will summarize a series of studies we have recently performed on semiconductor quantum wells in the presence of a strong magnetic field. In one type of experiment, electron-hole pairs were incoherently prepared, but a macroscopic polarization spontaneously emerged and cooperatively decayed, emitting an intense SF burst. In another type of experiment, we observed the SR decay of coherent cyclotron resonance of ultrahigh-mobility two-dimensional electron gases, leading to a decay rate that is proportional to the electron density. These results show that cooperative effects in solid-state systems are not merely small corrections that require exotic conditions to be observed; rather, they can dominate the nonequilibrium dynamics and light emission processes of the entire system of interacting electrons.

Near-field probing of Bloch surface waves in a dielectric multilayer using photonic force microscopy

Andrey Fedyanin, Daniil Shilkin, Evgeny Lyubin, and Irina Soboleva

Doc ID: 262041 Received 06 Apr 2016; Accepted 07 Apr 2016; Posted 19 Apr 2016  View: PDF

Abstract: The potential of photonic force microscopy (PFM) for probing the optical near-field in the vicinity of a dielectric multilayer is demonstrated.An experimental study of Bloch surface waves (BSWs) using PFM is described in detail. The applied technique is based on measuring the BSW-induced gradient force acting on a probe particle combined with precise control of the distance between the particle and the multilayer surface. The BSW-induced potential profile measured using PFM is presented. The force interaction between the probe and the BSW evanescent field is numerically studied.The results indicate that a polystyrene particle with a diameter of 1~$\mu$m does not significantly perturb the BSW field and can be used to probe the optical near-field intensity in an elegant, non-invasive manner.

Controlling the entanglement of a L-type atom in abimodal cavity via atomic motion

Hassan Safari, Mohammad Javad Faghihi, and Mahnaz Ghorbani

Doc ID: 252289 Received 19 Oct 2015; Accepted 04 Apr 2016; Posted 05 Apr 2016  View: PDF

Abstract: In this paper, a model describing the interaction between a moving three-level atom and a two-mode cavity field with nondegenerate two-photon transitions is considered in the presence of intensity-dependent coupling and detuning parameters. In order to evaluate the entanglement between the subsystems, the exact time-dependence of the state vector of the overall system is obtained. After studying the dynamics of the atom by considering atomic population inversion, entanglement of formation as a suitable measure of entanglement degree, is discussed, in detail. It is deduced from the numerical results that, the duration and the maximum amount of entanglement criteria can be suitably controlled by appropriately choosing the intensity-dependent nonlinearity function, the field-mode structure parameters and detuning.

Saturable and inverse saturable absorption in multi-walled-carbon-nano-tubes-doped fast Sol-gel hybrid glasses

Raphi Dror, ZeeV Burshtein, Raz Gvishi, and Mariana Pokrass

Doc ID: 232480 Received 14 Jan 2015; Accepted 10 Apr 2015; Posted 10 Apr 2015  View: PDF

Abstract: Dynamics of saturable absorption and inverse saturable absorption of Multi walled carbon nano tubes (MWCNT)-doped fast Sol-gel hybrid glasses was studied by optical transmission of 532-nm laser beam pulses at two extreme conditions: 6-ns long temporally isolated single pulses up to 0.02 J/cm2, and a pulse train at different intensities in the range 0.72-10.7 kW/cm2 (quasi-CW illumination). The temporally isolated single pulses were analysed by the slow saturable absorber limit; The quasi-CW illumination at steady state was analysed by the fast inverse saturable absorber limit. A fresh, corrected solution to the rate equation was developed for the latter. The time dependence of reaching steady state absorption in the quasi-CW case was analysed by a numerical simulation of a state model. The single-pulse case analysis yields a ground-state density N=5.1×1015cm-3, a ground-state absorption cross-section σgs=5.5×10-15cm2 , and a first excited-state absorption cross-section σes1=3.6×10-15cm2. The quasi-CW case analysis is consistent with the occurrence of the MWCNT transition upon illumination into a highly absorbing/scattering state ("plasma" state). The analysis yields a ground-state concentration estimation N=3.2×1015cm-3, and a ground-state absorption cross-section σgs=6.3×10-15cm2. The "plasma" lower-state absorption/ scattering cross-section is σes2=2.3×10-14cm2. The light-intensity dependent transition rate between the first MWCNT excited-state and its "plasma" lower state followed the relation τ-1inc[s-1]=12.25exp(4×10-7I[W/cm2]); the transition rate between the lowest "plasma" state and the MWCNT ground-state, was also light-intensity dependent, following the relation τ-1[s-1]=3.5exp(2.54×10-7I[W/cm2]).

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