Accepted papers to appear in an upcoming issue
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Effective collinear optical pumping for nuclear spin polarization
- received 04/28/2014; accepted 08/06/2014; posted 08/07/2014; Doc. ID 210900
- [full text: PDF (1709) KB)]
- Abstract: By numerically solving the density matrix equations, we show that the laser frequency ramping method by means of position-dependent Zeeman splitting can efficiently polarize nuclear spin of atoms/ions in an accelerator beamline. This minimizes a quantum phenomenon, coherent population trapping, which limits the optical pumping efficiency in the polarized beam line for radioactive nuclear spin polarization. We consider the 8Li atomic system interacting with two circularly polarized laser beams in the presence of time-dependent magnetic field. From numerical results, we find that optimum frequency ramping allows efficient optical pumping for a short interaction time, e.g. 2 μs.
- (020.1670) Atomic and molecular physics : Coherent optical effects
- (020.2930) Atomic and molecular physics : Hyperfine structure
- (140.5560) Lasers and laser optics : Pumping
Quantum Correlations of Quadratic Optomechanical Oscillator
- received 06/04/2014; accepted 08/05/2014; posted 08/18/2014; Doc. ID 213449
- [full text: PDF (1434) KB)]
- Abstract: Quantum optomechanical system serves as an interface for coupling between photons, excitons and mechanical vibrations. We use the quantum Langevin approach to study a hybrid system which contains a single undoped semiconductor quantum-well in a cavity, where one of its mirrors is a thin dielectric membrane having quadratic response to the cavity fields. A decorrelation method is employed to solve for a large number of coupled equations. Transient mean numbers of cavity photons, moving membrane and exciton we obtain the two-boson correlation functions for the cavity field, membrane oscillator number, and the cross-correlation. The nonclassical quantum statistical properties provide useful insights of the quadratic optomechanical system.
- (200.4880) Optics in computing : Optomechanics
- (270.0270) Quantum optics : Quantum optics
- (120.4880) Instrumentation, measurement, and metrology : Optomechanics
Nonlinear optics of graphene in the presence of Rabi oscillation
- received 06/02/2014; accepted 08/04/2014; posted 08/06/2014; Doc. ID 213288
- [full text: PDF (3560) KB)]
- Abstract: When graphene is subject to a strong light field, its nonlinear optical response allows only odd harmonic emissions because of a centrosymmetric structure. We demonstrate that this limitation no longer holds when the generation of an electric current density is considered within a quantum theory, because of the involvement of the Rabi oscillation in the nonlinear optical response. By transforming the time-dependent Dirac equation into the length gauge, the Rabi frequency in graphene can be defined, allowing the identification of the Rabi coupling effect on the current-induced harmonic spectra. In particular, a peak at the spectral position of the second harmonic of the incident light can be generated in graphene when the intensity of the incident light causes the Rabi frequency to become comparable to the frequency of the incident light, which was ever demonstrated in ZnO with a measurement of carrier- envelope-offset frequency in Phys. Rev. Lett. 90, 217404 (2003). Moreover, as the light intensity increases, we show that a broadband harmonic spectrum is generated and that a compact electron distribution caused by multi-photon absorptions is produced because of the highly nonlinear effects associated with the Rabi oscillation.
- (160.4330) Materials : Nonlinear optical materials
- (190.2620) Nonlinear optics : Harmonic generation and mixing
- (190.4180) Nonlinear optics : Multiphoton processes
- (190.4400) Nonlinear optics : Nonlinear optics, materials
- (270.6620) Quantum optics : Strong-field processes
Disordered Photonic Crystals: A Cluster-Coherent-Potential Approach using Photonic Wannier Functions
- received 05/12/2014; accepted 07/31/2014; posted 08/01/2014; Doc. ID 211751
- [full text: PDF (1950) KB)]
- Abstract: We present a Cluster-Coherent-Potential Approach for disordered Photonic Crystals that is based on maximally localized Wannier functions. In particular, the Wannier basis facilitates an efficient representation of the photonic band structure of a defect-free Photonic Crystal and the Green's function thereof which we discuss first. Moreover, the Wannier basis allows for adapting elaborate approaches developed for the analysis of disorder in electronic and phononic systems to Photonic Crystals. Our detailed studies reveal that neither the Virtual Crystal Approximation nor the single-site Coherent Potential Approximation provide a reliable description of the effects of disorder in Photonic Crystals. Rather, we demonstrate that a cluster based Coherent-Potential Approximation yields qualitatively and quantitatively useful results even for strong disorder. In all these approaches we include multiple bands, enforce the proper translational properties of the effective medium and incorporate interaction beyond nearest neighbor coupling. We also discuss the efficient evaluation of the corresponding system of equations. Our results establish a firm basis for various extensions such as to the theory of Anderson localization or random lasing in disordered Photonic Crystals.
- (050.1755) Diffraction and gratings : Computational electromagnetic methods
- (050.5298) Diffraction and gratings : Photonic crystals
- (160.5298) Materials : Photonic crystals
(PNR2014) Photon-number uncertainty in a superconducting transition-edge sensor beyond resolved-photon-number determination
- received 06/20/2014; accepted 07/28/2014; posted 08/01/2014; Doc. ID 214380
- [full text: PDF (355) KB)]
- Abstract: As part of an effort to extend fundamental single-photon measurements into the macroscopic regime, we explore how best to assign photon-number uncertainties to output waveforms of a superconducting transition edge sensor (TES) and how those assignments change over that extended dynamic range. Three methods are used. At the lowest photon numbers (up to 20 photons), the widths of histogram peaks of individual waveforms. From 100 to 1000 photons, mean waveforms are used to create a photon-number scale. The photon-number uncertainty of the detector in this range is given by the excess of the total variance of the photon number obtained from individual waveforms on this scale beyond the shot noise due to the source. In the mid-range (from 10 to 100 photons), including a range where the two other methods do not produce definitive results, we fit waveforms to several adjacent mean waveforms to estimate the photon-number uncertainty. A 1~standard deviation uncertainty in photon number of no more than $\pm1$ is found for pulses of up to 100 photons.
- (040.3780) Detectors : Low light level
- (040.5570) Detectors : Quantum detectors
(30th Anniversary) (Invited) Mini-review: Spatial solitons supported by localized gain
- received 06/02/2014; accepted 07/28/2014; posted 08/08/2014; Doc. ID 213280
- [full text: PDF (1754) KB)]
- Abstract: The creation of stable 1D and 2D localized modes in lossy nonlinear media is a fundamental problem in optics and plasmonics. This article gives a short review of theoretical methods elaborated for this purpose, using localized gain applied at one or several "hot spots"(HSs). The introduction surveys a broad class of models for which this approach was developed. Other sections focus in some detail on basic 1D continuous and discrete systems, where the results can be obtained, partly of fully, in an analytical form (verified by comparison with numerical results), which provides a deeper insight into the nonlinear dynamics of optical beams in dissipative nonlinear media. In particular, considered are the single and double HS in the usual waveguide with the self-focusing (SF) or self-defocusing (SDF) Kerr nonlinearity, which gives rise to rather sophisticated results, in spite of apparent simplicity of the model; solitons attached to a PT -symmetric dipole embedded into the SF or SDF medium; gap solitons pinned to an HS in a Bragg grating (BG); and discrete solitons in a 1D lattice with a "hot site".
- (140.3280) Lasers and laser optics : Laser amplifiers
- (190.0190) Nonlinear optics : Nonlinear optics
- (190.4360) Nonlinear optics : Nonlinear optics, devices
- (230.4320) Optical devices : Nonlinear optical devices
- (190.6135) Nonlinear optics : Spatial solitons
(LIM2014) Dichroic colored luster of laser-induced silver nanoparticle gratings buried in dense inorganic films
- received 06/12/2014; accepted 07/25/2014; posted 08/08/2014; Doc. ID 213967
- [full text: PDF (3792) KB)]
- Abstract: The paper deals with the colorimetric properties of silver nanoparticle gratings buried in a dense titania film that result from a continuous wave laser-induced self-organization process. The samples exhibit shinning colors in the direction of the specular reflection, which are very sensitive to polarization. We show that a large color gamut and a tunable dichroism can be reached by varying the exposure conditions. We also discuss about the physical meaning of the observed variations in the dichroism. This laser process provides a single pass marking with a micrometer resolution and could be useful to develop innovative solutions in fields like active color displays, security, polarization imaging or design.
- (140.3390) Lasers and laser optics : Laser materials processing
- (330.1710) Vision, color, and visual optics : Color, measurement
- (160.4236) Materials : Nanomaterials
- (310.6628) Thin films : Subwavelength structures, nanostructures
Analysis of silica filled-slot waveguides based on hyperbolic metamaterials: erratum
- received 08/12/2014; accepted ; posted 08/12/2014; Doc. ID 220647
- [full text: PDF (374) KB)]
- Abstract: In this erratum we have replaced the wrong figures and corrected several misprints that were found in our recently published paper.
- (230.7370) Optical devices : Waveguides
- (160.3918) Materials : Metamaterials