426 Works

Editorial: 10th Anniversary

Martijn De Sterke
Editor-in-Chief Martijn de Sterke celebrates the tenth anniversary of Optics Express.

Editorial: 10th Anniversary

Martijn De Sterke
Editor-in-Chief Martijn de Sterke celebrates the tenth anniversary of Optics Express.

Phase velocity nonuniformity-resulted beam patterns in difference frequency generation

Daquan Lu, Liejia Qian, Yongzhong Li, Hua Yang, Heyuan Zhu & Dianyuan Fan
The evolution of the difference frequency generation between a planar pump wave and a focused signal wave has been numerically investigated in this paper. We show that, at the difference frequency wave, various beam patterns such as ring and moon-like, are resulted due to the nonuniform distribution of phase velocity in the focused signal wave. The subluminal and superluminal regions can be identified by the intersection of two generated beam profiles that correspond to a...

Phase velocity nonuniformity-resulted beam patterns in difference frequency generation

Daquan Lu, Liejia Qian, Yongzhong Li, Hua Yang, Heyuan Zhu & Dianyuan Fan
The evolution of the difference frequency generation between a planar pump wave and a focused signal wave has been numerically investigated in this paper. We show that, at the difference frequency wave, various beam patterns such as ring and moon-like, are resulted due to the nonuniform distribution of phase velocity in the focused signal wave. The subluminal and superluminal regions can be identified by the intersection of two generated beam profiles that correspond to a...

Fabrication of a dual-tier thin film micropolarization array

Viktor Gruev, Alessandro Ortu, Nathan Lazarus, Jan Van Der Spiegel & Nader Engheta
A thin film polarization filter has been patterned and etched using reactive ion etching (RIE) in order to create 8 by 8 microns square periodic structures. The micropolarization filters retain the original extinction ratios of the unpatterned thin film. The measured extinction ratios on the micropolarization filters are ~1000 in the blue and green visible spectrum and ~100 in the red spectrum. Various gas combinations for RIE have been explored in order to determine the...

Fabrication of a dual-tier thin film micropolarization array

Viktor Gruev, Alessandro Ortu, Nathan Lazarus, Jan Van Der Spiegel & Nader Engheta
A thin film polarization filter has been patterned and etched using reactive ion etching (RIE) in order to create 8 by 8 microns square periodic structures. The micropolarization filters retain the original extinction ratios of the unpatterned thin film. The measured extinction ratios on the micropolarization filters are ~1000 in the blue and green visible spectrum and ~100 in the red spectrum. Various gas combinations for RIE have been explored in order to determine the...

Rapid prototyping of optical components for surface plasmon polaritons

Roman Kiyan, Carsten Reinhardt, Sven Passinger, Andrei L. Stepanov, Andreas Hohenau, Joachim R. Krenn & Boris N. Chichkov
Advanced femtosecond laser technology allows the fabrication of arbitrary 2D and 3D dielectric micro- and nanoscale structures by two-photon polymerization (2PP). In this paper, we present first investigations on excitation of surface plasmon polaritons (SPPs) on dielectric 2D structures fabricated on metal surfaces with this technology. Straight and curved line- and dot- structures built of the negative-tone photoresist ORMOCER (organically modified ceramic) are investigated by plasmon leakage radiation microscopy. Polarization dependent excitation efficiencies and focusing...

Rapid prototyping of optical components for surface plasmon polaritons

Roman Kiyan, Carsten Reinhardt, Sven Passinger, Andrei L. Stepanov, Andreas Hohenau, Joachim R. Krenn & Boris N. Chichkov
Advanced femtosecond laser technology allows the fabrication of arbitrary 2D and 3D dielectric micro- and nanoscale structures by two-photon polymerization (2PP). In this paper, we present first investigations on excitation of surface plasmon polaritons (SPPs) on dielectric 2D structures fabricated on metal surfaces with this technology. Straight and curved line- and dot- structures built of the negative-tone photoresist ORMOCER (organically modified ceramic) are investigated by plasmon leakage radiation microscopy. Polarization dependent excitation efficiencies and focusing...

Optical trapping of director structures and defects in liquid crystals using laser tweezers

Ivan I. Smalyukh, Daniel S. Kaputa, Aliaksandr V. Kachynski, Andrey N. Kuzmin & Paras N. Prasad
We demonstrate optical manipulation of structures and defects in liquid crystals (LCs). The effective refractive index depends on the LC molecular orientations and the laser beam’s polarization. We use the orientation-mediated refractive index contrast for the laser trapping in LCs with a homogeneous composition, but with spatially-varying patterns of molecular orientations. Tightly-focused polarized beams allow for optical trapping of disclinations and their clusters, dislocations and oily streaks, cholesteric fingers and focal conic domains, etc. We...

Optical trapping of director structures and defects in liquid crystals using laser tweezers

Ivan I. Smalyukh, Daniel S. Kaputa, Aliaksandr V. Kachynski, Andrey N. Kuzmin & Paras N. Prasad
We demonstrate optical manipulation of structures and defects in liquid crystals (LCs). The effective refractive index depends on the LC molecular orientations and the laser beam’s polarization. We use the orientation-mediated refractive index contrast for the laser trapping in LCs with a homogeneous composition, but with spatially-varying patterns of molecular orientations. Tightly-focused polarized beams allow for optical trapping of disclinations and their clusters, dislocations and oily streaks, cholesteric fingers and focal conic domains, etc. We...

Finite element modeling of acoustic field induced by laser line source near surface defect

Yifei Shi, Zhonghua Shen, Xiaowu Ni, Jian Lu & Jianfei Guan
A numerical model of acoustic field induced by laser line source near the surface defect is established by finite element method (FEM), where a surface notch of rectangular shape has been introduced to represent the fatigue defect for the convenience of modeling. After calculating numerically the transient displacement distributions, which are generated by the laser irradiation, the ultrasonic wave modes on the surface and in the body of the plate material are presented in details....

Doppler optical cardiogram gated 2D color flow imaging at 1000 fps and 4D in vivo visualization of embryonic heart at 45 fps on a swept source OCT system

Adrian Mariampillai, Beau A. Standish, Nigel R. Munce, Cristina Randall, George Liu, James Y. Jiang, Alex E. Cable, I. Alex Vitkin & Victor X.D. Yang
We report a Doppler optical cardiogram gating technique for increasing the effective frame rate of Doppler optical coherence tomography (DOCT) when imaging periodic motion as found in the cardiovascular system of embryos. This was accomplished with a Thorlabs swept-source DOCT system that simultaneously acquired and displayed structural and Doppler images at 12 frames per second (fps). The gating technique allowed for ultra-high speed visualization of the blood flow pattern in the developing hearts of African...

Doppler optical cardiogram gated 2D color flow imaging at 1000 fps and 4D in vivo visualization of embryonic heart at 45 fps on a swept source OCT system

Adrian Mariampillai, Beau A. Standish, Nigel R. Munce, Cristina Randall, George Liu, James Y. Jiang, Alex E. Cable, I. Alex Vitkin & Victor X.D. Yang
We report a Doppler optical cardiogram gating technique for increasing the effective frame rate of Doppler optical coherence tomography (DOCT) when imaging periodic motion as found in the cardiovascular system of embryos. This was accomplished with a Thorlabs swept-source DOCT system that simultaneously acquired and displayed structural and Doppler images at 12 frames per second (fps). The gating technique allowed for ultra-high speed visualization of the blood flow pattern in the developing hearts of African...

Finite element modeling of acoustic field induced by laser line source near surface defect

Yifei Shi, Zhonghua Shen, Xiaowu Ni, Jian Lu & Jianfei Guan
A numerical model of acoustic field induced by laser line source near the surface defect is established by finite element method (FEM), where a surface notch of rectangular shape has been introduced to represent the fatigue defect for the convenience of modeling. After calculating numerically the transient displacement distributions, which are generated by the laser irradiation, the ultrasonic wave modes on the surface and in the body of the plate material are presented in details....

Plasmonic materials in transparency and cloaking problems: mechanism, robustness, and physical insights

Andrea Alù & Nader Engheta
The possibility of making a given object transparent to the impinging radiation, or cloaking it, by employing a suitable metamaterial or plasmonic cover has been recently studied theoretically, showing how this technique may overcome the limitations of other currently available techniques. Here we discuss the underlying mechanisms, physical insights and some computer simulations on the role of such homogeneous isotropic metamaterial covers near their plasma frequency in order to dramatically reduce the fields scattered by...

Plasmonic materials in transparency and cloaking problems: mechanism, robustness, and physical insights

Andrea Alù & Nader Engheta
The possibility of making a given object transparent to the impinging radiation, or cloaking it, by employing a suitable metamaterial or plasmonic cover has been recently studied theoretically, showing how this technique may overcome the limitations of other currently available techniques. Here we discuss the underlying mechanisms, physical insights and some computer simulations on the role of such homogeneous isotropic metamaterial covers near their plasma frequency in order to dramatically reduce the fields scattered by...

Spatial mode discrimination using second harmonic generation

V. Delaubert, M. Lassen, D.R.N. Pulford, H-A. Bachor & C.C. Harb
Second harmonic generation (SHG) can be used as a technique for controlling the spatial mode structure of optical beams. We demonstrate experimentally the generation of higher-order spatial modes, and the possibility to use nonlinear phase matching as a predictable and robust technique for the conversion of transverse electric modes of the second harmonic output. The details of this effect are well described by our wave propagation models, which include mode dependent phase shifts. This is,...

Parametric amplification and compression to ultrashort pulse duration of resonant linear waves

C. Aguergaray, T. V. Andersen, D. N. Schimpf, O. Schmidt, J. Rothhardt, T. Schreiber, J. Limpert, E. Cormier & A. Tünnermann
We report on an optical parametric amplification system which is pumped and seeded by fiber generated laser radiation. Due to its low broadening threshold, high spatial beam quality and high stability, the fiber based broad bandwidth signal generation is a promising alternative to white light generation in bulky glass or sapphire plates. We demonstrate a novel and successful signal engineering implemented in a setup for parametric amplification and subsequent recompression of resonant linear waves resulting...

Spatial mode discrimination using second harmonic generation

V. Delaubert, M. Lassen, D.R.N. Pulford, H-A. Bachor & C.C. Harb
Second harmonic generation (SHG) can be used as a technique for controlling the spatial mode structure of optical beams. We demonstrate experimentally the generation of higher-order spatial modes, and the possibility to use nonlinear phase matching as a predictable and robust technique for the conversion of transverse electric modes of the second harmonic output. The details of this effect are well described by our wave propagation models, which include mode dependent phase shifts. This is,...

Parametric amplification and compression to ultrashort pulse duration of resonant linear waves

C. Aguergaray, T. V. Andersen, D. N. Schimpf, O. Schmidt, J. Rothhardt, T. Schreiber, J. Limpert, E. Cormier & A. Tünnermann
We report on an optical parametric amplification system which is pumped and seeded by fiber generated laser radiation. Due to its low broadening threshold, high spatial beam quality and high stability, the fiber based broad bandwidth signal generation is a promising alternative to white light generation in bulky glass or sapphire plates. We demonstrate a novel and successful signal engineering implemented in a setup for parametric amplification and subsequent recompression of resonant linear waves resulting...

Integral holography: white-light single-shot hologram acquisition

Natan T. Shaked, Joseph Rosen & Adrian Stern
A new method for obtaining digital Fourier holograms, under spatially incoherent white-light illumination and in a single camera shot, is presented. Multiple projections of the 3-D scene are created in the image plane of a microlens array, and a digital camera acquires the entire projections in a single shot. Then, each projection is computer processed to yield a single point in a Fourier hologram. The new method, designated as integral holography, is proved for the...

Integral holography: white-light single-shot hologram acquisition

Natan T. Shaked, Joseph Rosen & Adrian Stern
A new method for obtaining digital Fourier holograms, under spatially incoherent white-light illumination and in a single camera shot, is presented. Multiple projections of the 3-D scene are created in the image plane of a microlens array, and a digital camera acquires the entire projections in a single shot. Then, each projection is computer processed to yield a single point in a Fourier hologram. The new method, designated as integral holography, is proved for the...

Spatial solitons in nematic liquid crystals: from bulk to discrete

G. Assanto, A. Fratalocchi & M. Peccianti
We review theoretical and experimental results on spatial solitons in nematic liquid crystalline cells, including two-dimensional solitons in bulk and discrete solitons in one-dimensional waveguide arrays. In bulk we describe the propagation of continuous solitons in the presence of adjustable walk-off, their interaction with light-induced defects and refraction-reflection at a voltage-tunable interface. In optical lattices we address the transition from discrete diffraction to localization, as well as all-optical beam steering.

Spatial solitons in nematic liquid crystals: from bulk to discrete

G. Assanto, A. Fratalocchi & M. Peccianti
We review theoretical and experimental results on spatial solitons in nematic liquid crystalline cells, including two-dimensional solitons in bulk and discrete solitons in one-dimensional waveguide arrays. In bulk we describe the propagation of continuous solitons in the presence of adjustable walk-off, their interaction with light-induced defects and refraction-reflection at a voltage-tunable interface. In optical lattices we address the transition from discrete diffraction to localization, as well as all-optical beam steering.

Three-dimensional optical manipulation using four collimated intersecting laser beams

J. Huisken, J. Swoger & E.H.K. Stelzer
The optical Earnshaw theorem states that a small particle cannot be trapped solely by scattering forces. This limitation is overcome in a novel differential all-optical manipulator. It utilizes four collimated laser beams arranged along the axes of a tetrahedron to confine and move a microscopic sample in an aqueous medium. By adjusting the intensity of each beam individually the magnitude and direction of the optical forces acting on the sample, and via these its position,...

Resource Types

  • Collection
    426

Publication Year

  • 2007
    426