We suggest using an evanescent wave around a thin fiber to trap atoms. We show that the gradient force of a red-detuned evanescent-wave field in the fundamental mode of a silica fiber can balance the centrifugal force when the fiber diameter is about two times smaller than the wavelength of the light and the component of the angular momentum of the atoms along the fiber axis is in an appropriate range. As an example, the system should be realizable for Cesium atoms at a temperature of less than 0.29 mK using a silica fiber with a radius of 0.2 $μ$m and a 1.3-$μ$m-wavelength light with a power of about 27 mW.
This is a comment on "Guiding, Focusing, and Sensing on the Subwavelength Scale Using Metallic Wire Arrays" by G. Shvets, S. Trendafilov, J. B. Pendry and A. Sarychev published in Phys. Rev. Lett. 99, 053903 (2007), which demonstrates that the endoscope proposed in the letter does not demonstrate satisfactory subwavelength imaging performance.
Subwavelength imaging by microsphere lenses is a promising label-free super-resolution imaging technique. There is a growing interest to use live cells to replace the widely used non-biological microsphere lenses. In this work, we demonstrate the use of yeast cells for such imaging purpose. Using fiber-based optical trapping technique, we successfully trapped a chain of yeast cells and bring them to the vicinity of imaging objects. These yeast cells work as near-field magnifying lenses and simultaneously pick up the sub-diffraction information of the nanoscale objects under each cell and proje…
The aim of this review is to cover recent developments in the mathematical analysis of subwavelength resonators. The use of sophisticated mathematics in the field of metamaterials is reported, which provides a mathematical framework for focusing, trapping, and guiding of waves at subwavelength scales. Throughout this review, the power of layer potential techniques combined with asymptotic analysis for solving challenging wave propagation problems at subwavelength scales is demonstrated.
We demonstrate that graphene placed on top of structured substrates offers a novel approach for trapping and guiding surface plasmons. A monolayer graphene with a spatially varying curvature exhibits an effective trapping potential for graphene plasmons near curved areas such as bumps, humps and wells. We derive the governing equation for describing such localized channel plasmons guided by curved graphene and validate our theory by the first-principle numerical simulations. The proposed confinement mechanism enables plasmon guiding by the regions of maximal curvature, and it offers a versatil…
Silicon carbide (SiC) displays a unique combination of optical and spin-related properties that make it interesting for photonics and quantum technologies. However, guiding light by total internal reflection can be difficult to achieve, especially when SiC is grown as thin films on higher index substrates, like Silicon. Fabricating suspended, subwavelength waveguides requires a single lithography step and offers a solution to the confinement problem, while preserving the design flexibility required for a scalable and complete photonic platform. Here we present a design for such platform, that …
An on-chip multi-grating device is proposed to interface single-atoms and integrated photonic circuits, by guiding and focusing lasers to the area with ~10um above the chip for trapping, state manipulation, and readout of single Rubidium atoms. For the optical dipole trap, two 850 nm laser beams are diffracted and overlapped to form a lattice of single-atom dipole trap, with the diameter of optical dipole trap around 2.7um. Similar gratings are designed for guiding 780 nm probe laser to excite and also collect the fluorescence of 87Rb atoms. Such a device provides a compact solution for future…
Optical metasurfaces of subwavelength pillars have provided new capabilities for the versatile definition of the amplitude, phase, and polarization of light. In this work, we demonstrate that an efficient dielectric metasurface lens can be used to trap and image single neutral atoms with a long working distance from the lens of 3 mm. We characterize the high-numerical-aperture optical tweezers using the trapped atoms and compare with numerical computations of the metasurface lens performance. We predict that future metasurfaces for atom trapping will be able to leverage multiple ongoing develo…
We analyze evanescent fields of laser written waveguides and show that they can be used to trap atoms close to the surface of an integrated optical atom chip. In contrast to subwavelength nanofibres it is generally not possible to create a stable trapping potential using only the fundamental modes. This is why we create a stable trapping potential by using two different laser colors, such that the waveguide supports two modes for the blue detuned laser, while for the red detuned light the waveguide has only a single mode. In particular, we study such a two-color trap for Cesium atoms, and calc…
We introduce a novel approach for all-optical trapping and manipulation of absorbing aerosol particles based on a photophoretic force. We demonstrate experimentally, in open air, the robust three-dimensional guiding of agglomerates of carbon nanoparticles with the size spanned for two orders of magnitude, from 100 nanometers to 10 microns, over the distances of a few millimeters, as well as their acceleration up to velocities of 1 cm/s and simultaneous trapping of a large number of particles.
In this letter, we propose a new proof-of-concept of optical nano-tweezer on the basis of a pair of dielectric rectangular rods capable of generating a novel class of controlled finite-volume near field light capsules. The finite-difference time-domain simulations of light spatial structure and optical trapping forces of the gold nanoparticle immersed in water demonstrate the physical concept of an in-plane subwavelength optical capsule, integrated with the microfluidic mesoscale device. It is shown that refractive index and distance between dielectric rectangular rods can control the shape an…
Subwavelength plasmonic waveguides show the unique ability of strongly localizing (down to the nanoscale) and guiding light. These structures are intrinsically two-way optical communication channels, providing two opposite light propagation directions. As a consequence, when light is coupled to these planar integrated devices directly from the top (or bottom) surface using strongly focused beams, it is equally shared into the two opposite propagation directions. Here, we show that symmetry can be broken by using incident circularly polarized light, on the basis of a spin-orbital angular moment…
In this work, we optically trapping microparticles with higher order Frozen Wave using holographic optical tweezers. Frozen Waves are diffraction resistant optical beams, obtained by superposing copropagating Bessel beams with the same frequency and order, obtaining efficient modeling of its shape. Based on this, we developed a holographic optical tweezers system for the generation of Frozen Waves and with this, it was possible to create traps in a stable way for the trapping and guiding of the microparticles in the transverse plane. The experimental results show that it is possible to obtain …
We present an optical investigation of surface plasmon polaritons propagating along nanoscale Au-wires, lithographically defined on GaAs substrates. A two-axis confocal microscope was used to perform spatially and polarization resolved measurements in order to confirm the guiding of surface plasmon polaritons over lengths ranging from $5-20 μm$ along nanowires with a lateral dimension of only $\approx 100 nm$. Finite difference time domain simulations are used to corroborate our experimental observations and highlight the potential to couple proximal quantum dot emitters to propagating plasmon…
In this work we report two designs of subwavelength fibers packaged for practical terahertz wave guiding. We describe fabrication, modeling and characterization of microstructured polymer fibers featuring a subwavelength-size core suspended in the middle of a large porous outer cladding. This design allows convenient handling of the subwavelength fibers without distorting their modal profile. Additionally, the air-tight porous cladding serves as a natural enclosure for the fiber core, thus avoiding the need for a bulky external enclosure for humidity-purged atmosphere. Fibers of 5 mm and 3 mm …
We provide the first demonstration of nonlinear self-trapping of light in solutions of food coloring dyes, leading to dirt cheap soliton waveguides. The optical self-focusing nonlinearity observed in such solutions is attributed to the optical absorption force acting on dye molecules, as the thermal effect at relatively higher power results in a self-defocusing nonlinearity. We found the nonlinear response increases when the laser wavelength is switched to near the peak absorption for all food dyes tested. Furthermore, the absorption-dependent nonlinearity can be tuned by making purposive samp…
Tailored multipolar optical trapping with higher-order structured light
The Institute of Optics, University of Rochester（罗切斯特大学光学研究所）；Department of Physics, University of Rochester（罗切斯特大学物理系）；Center for Coherence and Quantum Optics, University of Rochester（罗切斯特大学相干与量子光学中心）
Optical binding allows creation of mechanically stable nanoparticle configurations owing to formation of self-consistent optical trapping potentials. While the classical diffraction limit prevents achieving deeply subwavelength arrangements, auxiliary nanostructures enable tailoring optical forces via additional interaction channels. Here, a dimer configuration next to metal surface was analyzed in details and the contribution of surface plasmon polariton waves was found to govern the interaction dynamics. It was shown that the interaction channel, mediated by resonant surface waves, enables a…
We demonstrate that the introduction of a subwavelength periodic modulation into a metallic structure strongly modifies the guiding characteristics of the surface plasmon modes supported by the system. Moreover, it is also shown how a new type of a tightly confined surface plasmon polariton mode can be created by just milling a periodic corrugation into a metallic ridge placed on top of a metal surface.
In this work, we present the experimental optical trap of microparticles with an Airy beams array using a holographic optical tweezers. The Airy beams array are attractive for optical manipulation of particles owing to their non--diffracting and autofocusing properties. An Airy beams array is composed of N Airy beams which accelerate mutually and symmetrically in opposite direction, for different ballistic trajectories, that is, with different initial launch angles. Based on this, we developed a holographic optical tweezers system for the generation of non-diffracting beams and with it, we inv…
Osmotic conditions play an important role in the cell properties of human red blood cells (RBCs), which are crucial for the pathological analysis of some blood diseases such as malaria. Over the past decades, numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes. Here, we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions. Specifically, we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three …
We report trapping and propagation of photonic Dirac mode in a helically twisted hollow core photonic crystal fiber (HC-PCF) where the trapped light in the hollow (air) defect can preserve the orbital angular momentum (OAM). We show that a photonic Dirac point can emerge even in a twisted system for a suitable choice of curvilinear coordinate and the related waveguide defect modes defined in the new basis can preserve the associated OAM during axial translation. The effect of twist rate, defect geometry and crystal dimension on the propagation of OAM carrying trapped Dirac modes is critically …
Optical nanofibres are used to confine light to subwavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical nanofibre into a magneto-optical trap for $^{87}$Rb atoms. The nanofibre, with a waist diameter of $\sim$700 nm, supports both the fundamental and first group of higher order modes and is used for atomic fluorescence and absorption studie…
We experimentally realize an optical fiber ring resonator that includes a tapered section with subwavelength-diameter waist. In this section, the guided light exhibits a significant evanescent field which allows for efficient interfacing with optical emitters. A commercial tunable fiber beam splitter provides simple and robust coupling to the resonator. Key parameters of the resonator such as its out-coupling rate, free spectral range, and birefringence can be adjusted. Thanks to the low taper- and coupling-losses, the resonator exhibits an unloaded finesse of F=75+/-1, sufficient for reaching…
Research School of Physics, Australian National University（澳大利亚国立大学物理研究学院）；School of Physics and Engineering, ITMO University（ITMO大学物理与工程学院）；Nanophotonic Systems Laboratory, Department of Mechanical and Process Engineering, ETH Zürich（苏黎世联邦理工学院机械与工艺工程系纳米光子系统实验室）
Wave modes induced by cross-phase reshaping of a probe photon in the guiding structure of a periodic train of temporal pulses are investigated theoretically with emphasis on exact solutions to the wave equation for the probe. The study has direct connection with recent advances on the issue of light control by light, the focus being on the trapping of a low-power probe by a temporal sequence of periodically matched high-power pulses of a dispersion-managed optical fiber. The problem is formulated in terms of the nonlinear optical fiber equation with averaged dispersion, coupled to a linear equ…
