This PDF file contains the front matter associated with SPIE Proceedings Volume 10252, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

We observed the collective motion of colloidal particles moving along a circular path in water as a model system of artificial active matter. The particles were driven by optical vortex using holographic optical tweezer. They exhibit rhythmic motion with spontaneous formation of clusters and their dissociation by hydrodynamic interaction. The hydrodynamic interaction in spatially confined system alter their rhythmic motion dramatically. For example, we found that the relative magnitude of the angular velocity for a doublet to a singlet reversed in free space and in strongly confined system. The transition of rhythmic motions was observed by varying spatial confinement.

We present a novel manipulation technique for living cyanobacteria on a plasmonic substrate. Upon plasmon excitation, a local temperature around the excitation area was elevated, leading to a microbubble formation in water. Subsequently, living cyanobacteria were transported to the microbubble by a thermal convection. The cyanobacteria were permanently fixed on the area even after switching off the plasmon excitation. We found that about a half of the fixed cyanobacteria were alive. We succeeded in a micro-ring pattern of living cyanobacteria by the technique.

PhotoAcoustic (PA) imaging is a promising imaging method using the pulsed-laser light source and ultrasound detector. PA image shows the features of optical contrast in biological tissue with ultrasound-like depth and resolution. In the human body, Hemoglobin of the blood is strong optical absorber, so the high-contrast blood distribution (vascular) image is obtained by PA imaging. Recently, FUJIFILM has developed the PA imaging system to explore its application in medical imaging field. In this system, the fusion of PA and conventional ultrasound image is realized, for example, ultrasound Doppler image is superposed to the PA and B-mode image. The system features and some results of clinical studies will be introduced.

Metallic nanoparticles with diameters from 10 nm to 250 nm can be optically trapped and manipulated in 3D using a single tightly focused near infrared laser beam. This will result in a significant heating of the particle and its vicinity, with temperature increases easily reaching hundreds degrees Celsius. If such a hot metallic nanoparticle is brought into the contact zone between two cells or vesicles, this local temperature increase can cause a total fusion of the selected cells or vesicles. Upon fusion, both the membrane and the cargos become completely mixed and we also show that the cells remain viable after fusion. The presented method has potential for single-cell targeted drug delivery and for the creation of hybrid cells.

Molecular dynamics of glutamate receptor, which is major neurotransmitter receptor at excitatory synapse located on neuron, is essential for synaptic plasticity in the complex neuronal networks. Here we studied molecular dynamics in an optical trap of AMPA-type glutamate receptor (AMPAR) labeled with quantum-dot (QD) on living neuronal cells with fluorescence imaging and fluorescence correlation spectroscopy (FCS). When a 1064-nm laser beam for optical trapping was focused on QD-AMPARs located on neuronal cells, the fluorescence intensity of QD-AMPARs gradually increased at the focal spot. Using single-particle tracking of QD-AMPARs on neurons, the average diffusion coefficient decreased in an optical trap. Moreover, the decay time obtained from FCS analysis increased with the laser power and the initial assembling state of AMPARs depended on culturing day, suggesting that the motion of QD-AMPAR was constrained in an optical trap.

A fundamental problem of using photonic states as carriers of quantum information is that they interact weakly with matter and that the interaction volume is typically limited by the wavelength of light. The use of metallic structures in quantum plasmonics has the potential to alleviate these problems. Here, we present the first results showing that a single subwavelength plasmonic nanoaperture can controllably modify the quantum state of light. We achieve this effect by using a specially engineered two photon state to match the properties of the nanoaperture.

Single angular momentum (OAM) mode emissions from a vertical cavity surface emitting laser (VCSEL) were demonstrated by an external optical feedback using computer generated holograms, which are optimized on the OAM modal gain of the free-running VCSEL. Side-mode suppression ratio of more than 23 dB was achieved for the OAM modes with l = ±1.

We experimentally generate the Bessel-Gauss coherence functions using the cross-correlations between the two speckle patterns obtained using the perfect optical vortices (POV) of different orders. POV beams are generated using the Fourier transform of Bessel-Gauss beams by displaying the axicon hologram on spatial light modulator. A ground glass plate is used for scattering POV beams and the speckles are recorded. The cross-correlation function of two speckle patterns is Bessel-Gauss functions whose order is given by the difference in the orders of two POV beams used for scattering. The auto-correlation function of these speckles is Bessel-Gauss function of order zero.

Light Robotics is a new field of research where ingredients from photonics, nanotechnology and biotechnology are put together in new ways to realize light-driven robotics at the smallest scales to solve major challenges primarily within the nanobio-domain but not limited hereto. Exploring the full potential of this new ‘drone-like’ light-printed, light-driven, light-actuated micro- and nanorobotics in challenging geometries requires a versatile and real-time reconfigurable light addressing that can dynamically track a plurality of tiny tools in 3D to ensure real-time continuous light-delivery on the fly. Our latest developments in this new and exciting research area will be reviewed.

We present the realization and analysis of tailored vector fields including polarization singularities. The fields are generated by a holographic method based on an advanced system including a spatial light modulator. We demonstrate our systems capabilities realizing specifically customized vector fields including stationary points of defined polarization in its transverse plane. Subsequently, vectorial flowers and spider webs as well as unique hybrid structures of these are introduced, and embedded singular points are characterized. These sophisticated light fields reveal attractive properties that pave the way to advanced application in e.g. optical micromanipulation. Beyond particle manipulation, they contribute essentially to actual questions in singular optics.

We reported on high average power ultraviolet (UV) picosecond optical vortex generation without any spatial separation of the phase singularity due to the walk-off effect by employing a pair of β-BaB₂O₄ and reversed β-BaB₂O₄ crystals. The UV vortex output power was measured to be 1.76 W, corresponding to the optical-optical conversion efficiency of 17 %.

A new method for the ultrafast rotation of ring-shaped optical lattices based on frequency-chirping of optical pulses was demonstrated in THz regime, which is three orders of magnitude faster than those by the conventional methods. Our optical lattice generator with a spatial light modulator is robust thanks to the 4-f configuration and enables us to flexibly control their rotational symmetry. The generated ultrafast-rotating ring-shaped optical lattices with a rotational frequency of 0.59 THz were successfully boosted from 5 μJ up to 125 μJ by using a home-built 4-pass Ti:sapphire amplifier without any limitation by optical damage to the spatial light modulator.

We originally perform an analytical form to explore the influence of the astigmatism on the degenerate effect in nearly hemispherical cavities. The frequency spectrum near hemispherical cavities clearly reveals that not only the difference of cavity lengths between each degeneracies but also frequency gaps have significant difference from non-hemispherical cavities. We further thoroughly demonstrate the laser experiment under the condition of nearly hemispherical cavities to confirm the theoretical exploration that the transverse topology of three-dimensional (3D) structured light in the degenerate cavities is well localized on the Lissajous curves.

Laser ablation is one of the most fundamental processes in laser processing, and the understanding of its dynamics is of key importance for controlling and manipulating the outcome. In this study, we propose a novel way of observing the dynamics in the time domain using an electro-optic sampling technique. We found that an electromagnetic field was emitted during the laser ablation process and that the amplitude of the emission was closely correlated with the ablated volume. From the temporal profile of the electromagnetic field, we analyzed the motion of charged particles with subpicosecond temporal resolution. The proposed method can provide new access to observing laser ablation dynamics and thus open a new way to optimize the laser processing.

We reported on a plasmonic metal Au nano-needle by nanosecond optical vortex pulse illumination. The Au nano-needle with a tip-diameter of <100 nm was structured by illumination of a single vortex pulse.

Remote acceleration of a molecular recognition will open an avenue for the control of various biological functions. Here, we have developed a new principle for the rapid macroscopic assembly based on the light-induced molecular recognition via nanoparticles. Remarkably, as an application of this principle, we have demonstrated the submillimetre network formation triggered by light-induced hybridization of zmol-level DNA within a few minutes. This finding will be used for the rapid and highly sensitive genetic screening without fluorescent labeling.

We presented the irradiation of optical vortex to ultraviolet (UV) curing resin structures a twisted polymer fiber. A continuous-wave ultraviolet optical vortex, focused at a glass cell containing the cure resin, allowed us to shape a twisted polymeric fiber with a diameter of a few micrometer and a length of ~160 μm with an exposure time of < 1 second. Twisted direction of the fiber was also controlled by inverting the handedness of the optical vortex.

Plasmon-induced photo-polymerization of the conductive polymer was performed on the Au-TiO₂ composite photo electrode. Thorough the examination of the spatial distribution of the conductive polymer which was deposited in the vicinity of metal nano-structures, the visualization of the spatially localized strong optical field have been achieved. Not only for the visualization of the generated strong optical field but also the determination of the absolute electrochemical potential for the generated hole for the oxidation of the monomer molecules. Using the present technique, the higher order resonances at the Au nanorod structures are also examined to generate highly-selective polymer deposition.

We discovered that a helical surface relief can be created in azo-polymer film merely by the irradiation of circularly-polarized light without any orbital angular momentum. The chirality of the surface relief was also determined by the handedness of the circular polarized light.

We fabricated semiconductor ZnO microspheres via the pulsed laser ablation in the superfluid helium. The scanning electron microscope observation revealed the high sphericity and smooth surface. We also observed whispering gallery mode resonances, the electromagnetic eigenmode resonances within the microspheres, in the cathodoluminescence spectrum, verifying the high symmetry of the fabricated microspheres. Further, we cross-sectioned the microspheres with using focused ion beam. The scanning electron microscope observation of the cross section uncovers the existence of small holes within the microspheres. The inner structure examination helps us to understand the microscopic mechanism of our fabrication method.

We reported on crystalline silicon structures formed on a silicon (111) substrate through picosecond optical vortex pulse illumination. A crystalline silicon needle with a height of 20 µm was structured through single vortex pulse illumination. Sixteen overlaid vortex pulses shaped the silicon into a crystalline pillar with a height of ~45 µm.

Optical binding refers to an optically mediated inter-particle interaction that creates new equilibrium positions for closely spaced particles [1–5]. Optical binding of mesoscopic particles levitated in vacuum can pave the way towards the realisation of a large scale quantum bound array in cavity-optomechanics [6–9]. Recently we have demonstrated trapping and rotation of two mesoscopic particles in vacuum using a spatial-light-modulator-based approach to trap more than one particle, induce controlled rotation of individual particles, and mediate interparticle separation [10]. By trapping and rotating two vaterite particles, we observe intensity modulation of the scattered light at the sum and difference frequencies with respect to the individual rotation rates. This first demonstration of optical interference between two microparticles in vacuum has lead to a platform to explore optical binding. Here we demonstrate for the first time optically bound two microparticles mediated by light scattering in vacuum. We investigate autocorrelations between the two normal modes of oscillation, which are determined by the centre-of-mass and the relative positions of the two-particle system. In situ determination of the optical restoring force acting on the bound particles are based on measurement of the oscillation frequencies of the autocorrelation functions of the two normal modes, thereby providing a powerful and original platform to explore multiparticle entanglement in cavity-optomechanics.

Plasmonic tweezers based on nano-ring arrays on gold thin film are demonstrated. A cylindrical surface plasmon resonance is generated in the aperture of a nano-ring and a transmission peak results. When nano-slits are included to connect the nano-rings, the transmission peak becomes narrower. When the size of the aperture of the nano-ring is reduced, this peak is red-shifted. Both 0.5 μm and 1 μm polystyrene particles are trapped successfully by nano-ring arrays. A self-induced back-action effect is observed when a red-shifted laser beam is used. With multiple trapping sites provided by the nano-ring array, this type of plasmonic tweezers has huge potential to be integrated in lab-on-a-chip systems for life sciences research.

We synthesize, optically trap, and rotate individual nanovaterite crystals with a mean particle radius of 423 nm. Rotation rates of up to 4.9 kHz in heavy water are recorded [1]. Laser-induced heating due to residual absorption of the nanovaterite particle results in the superlinear behavior of the rotation rate as a function of trap power. A finite element method based on the Navier-Stokes model for the system allows us to determine the residual optical absorption coefficient for a trapped nanovaterite particle. This is further confirmed by the theoretical model. Our data reveal that the nanoparticle experiences a different Stokes drag torque or force depending on whether we consider rotational or translational motion, which is in a good agreement with the theoretical prediction of the rotational hot Brownian motion [2]. The data allow us to determine the correction factors for the local viscosity for both the rotational and translational motion of the nanoparticle. The use of nanovaterite particles opens up new studies for levitated optomechanics in vacuum [3–6] as well as microrheological properties of cells or biological media [7]. For these latter studies, nanovaterite offers prospects of microviscosity measurements in ultrasmall volumes and, due to its size, potentially simpler uptake by cellular media [8].

We investigated the optical binding between dielectric microparticles in the evanescent fields of the first group of higher order microfiber modes. Particle groups consisting of up to five particles were propelled along the fiber and neighboring interactions were experimentally investigated and supported by numerical simulation.

Atoms can be individually captured and guided by light through optical dipole-trapping. However, applying this to many atoms simultaneously has been difficult due to the low inertia of atoms. Recently dynamically-controlled laser beams achieved such demonstrations, enabling a bottom-up approach to form arbitrary atom lattices, deterministic atom loading, atom-sorting, and even single-atom-level machinery. Here we report the latest improvements of the single-atom-level dynamic holographic optical tweezers. With the hardware and software upgrades to be explained in the text, the overall performance has improved to form arbitrary 2D lattices of a size about N=20, with success probability exceeding 50%.

We demonstrate the transfer of orbital angular momentum to optically levitated microparticles in vacuum [1]. We prepare two-dimensional and three-dimensional optical potentials. In the former case the microparticle is placed within a Laguerre-Gaussian beam and orbits the annular beam profile with increasing angular velocity as the air drag coefficient is reduced. We explore the particle dynamics as a function of the topological charge of the levitating beam. Our results reveal that there is a fundamental limit to the orbital angular momentum that may be transferred to a trapped particle, dependent upon the beam parameters and inertial forces present. This effect was predicted theoretically [2] and can be understood considering the underlying dynamics arising from the link between the magnitude of the azimuthal index and the beam radius [3]. Whilst a Laguerre-Gaussian beam scales in size with azimuthal index `, recently we have created a “perfect” vortex beam whose radial intensity profile and radius are both independent of topological charge [4, 5]. As the Fourier transform of a perfect vortex yields a Bessel beam. Imaging a perfect vortex, with its subsequent propagation thus realises a complex three dimensional optical field. In this scenario we load individual silica microparticles into this field and observe their trajectories. The optical gradient and scattering forces interplay with the inertial and gravitational forces acting on the trapped particle, including the rotational degrees of freedom. As a result the trapped microparticle exhibits a complex three dimensional motion that includes a periodic orbital motion between the Bessel and the perfect vortex beam. We are able to determine the three dimensional optical potential in situ by tracking the particle. This first demonstration of trapping microparticles within a complex three dimensional optical potential in vacuum opens up new possibilities for fundamental studies of many-body dynamics, mesoscopic entanglement [6, 7], and optical binding [8, 9].

We studied the opto-mechanical response of droplets composed of cholesteric liquid crystal (ChLC) to a circularly polarized optical tweezers. Although the alignment of LC molecular within a droplet depends on the relative ratio of the droplet diameter d to the helical pitch p, the optically induced rotation was found to be asymmetric to the direction of circularly polarized light irrespective to the inner molecular alignment. We studied the rotation of the droplets with various sizes, helical pitch (strength of chirality) and different chirality. In the case of d/p ~ 1, the direction of the rotation was simply determined by chirality of ChLC and the rotation was also observed for linearly polarized light, which has already been reported by Yang et al.

In this work, hollow whispering gallery resonators with thin walls are filled with a water solution containing 500 nm nanoparticles. The quasi-droplet modes of the hollow resonator create an optical scattering force which pushes the particles around with velocities far exceeding 1.2 mm/s. The optical modes are observed to shift up to tens of GHz in the presence of the nanoparticle. By using counter propagating modes, the position and direction of the particles are controlled, this is the first time trapping and control of nanoparticles has been demonstrated in a quasi-droplet micoresonator.

In this work, we demonstrate an original single-nanoparticle deposition process based on near-field optical forces arising from much localized plasmonic resonant gap-mode. At first, nanoparticles exclusively made of fluorescent dye molecules are fabricated in aqueous colloidal suspension. Near-field optical forces are then used to attract and deposit single nanoparticles in the nanogap of plasmonic nanoantennas. This one-step deposition process allows targeted deposition of nanoscale materials directly from a colloidal dispersion to a few-nanometer large area of interest.

In this paper, we have demonstrated a nano-particle rotation above a plasmonic gold trimer nano-structure with a nanogap. We designed the plasmonic trimer nano-structure which has a resonant frequency matched to excitation and made it with electron beam lithography with metal lift-off process. At first, with an actively rotating linearly polarized beam excitation, we have realized a rotational motion of a trapped nano-particle synchronized to a polarization of beam. Next, we observed a nano-particle rotation using a circularly polarized beam. From the auto-correlation of position time trace with sinusoidal fitting, we confirmed a faster rotation of nano-particle than that of an actively rotating linearly polarized beam.

We proposed a technique to manipulate a metal particle in glass optically. The glass in the neighborhood of the laserheated metal particle softened; hence, the metal particle migrated in the glass. In our numerical calculation, the temperature difference in the metal particle generated the inhomogeneous distribution of the interfacial tension between melted metal particle and softened glass. The inhomogeneous distribution generated driving force. In this presentation, the experimental temperature measurement by using emitted light of the migrating metal particle in glass was discussed. The temperature was approximately 2400 K and corresponded with the numerical calculated temperature reported before.

Near-field optical forces arise from evanescent electromagnetic fields and can be advantageously used for on-chip optical trapping. In this work, we investigate how evanescent fields at the surface of photonic cavities can efficiently trap micro-objects such as polystyrene particles and bacteria. We study first the influence of trapped particle’s size on the trapping potential and introduce an original optofluidic near-field optical microscopy technique. Then we analyze the rotational motion of trapped clusters of microparticles and investigate their possible use as microfluidic micro-tools such as integrated micro-flow vane. Eventually, we demonstrate efficient on-chip optical trapping of various kinds of bacteria.

We investigate the optical manipulation of nanoparticles with the resonant nonlinear optical response. Efficient trapping of nanoparticles observed in experiments under the resonance condition is elucidated by considering optical nonlinearity. Also, we propose the flexible optical manipulations of nanoparticles that have gain by optical pumping. The pulling force and the rotational switching are demonstrated, where the stimulated emission from nanoparticles with inverted population is considered. These results show that utilizing nonlinear optical effect will greatly enhance the degrees of freedom to manipulate nanoparticles.

We experimentally demonstrate that non-chiral plasmonic nanostructured materials interacting with linearly polarized (non-chiral) light generate elliptically polarized (chiral) optical near-fields in local nano spaces around the materials.

Plasmonic enhancements of optical near-fields with metal nanostructures offer extensive potential for amplifying lightmatter interactions. We analytically formulate the enhancement of linear and nonlinear optical responses of molecular vibrations through resonant nanoantennas, based on a coupled-dipole model. We apply the formulae to evaluation of signal enhancement factors in the antenna-enhanced vibrational spectroscopy.

We investigate the wavelength dependence of localized plasmonic field distributions in a gold nanodimer structure under total internal reflection condition. Although a gold dimer structure is well known to induce strong localized mode at a nanogap, we find that the higher-order plasmonic modes are excited by the oblique light incidence and their interference effect enables us to observe the modification of localized filed distributions at the nano-scale even in a simple gold nanodimer structure depending on the detection wavelength. This change in the plasmonic field distribution would provide important knowledge for their potential applications such as plasmonic trapping, spectroscopy, and sensing.

Bow-tie nano-antennas are the kind of plasmonic structures that are widely used in optical applications to obtain strong electric fields in a limited volume. Their capability to enhance the incident light can be greatly improved by constructing these structures from several alternating metal/dielectric layers. Following this approach, we introduce and then analyze the performance of a multilayered Au/SiO₂ bow-tie nano-antenna in the finite-difference time-domain software. We show that the gold/silica thickness ratio of 50% leads to the improvement of the electric field enhancement on almost 50%, when compared to a monolithic gold device, which makes the proposed design attractive for various sensing applications.

We investigate the tight focusing of radially polarized ultrashort pulse laser beam. It is found that pulse delay phenomenon occurs near the focus. This is, near the focus, the photon travels slower than the speed of light.

The emission spectra of CdSe/ZnS core-shell dots have been monitored after the dilution of their toluene solution with organic solvents (toluene, n-hexane, diethyl ether, acetone, ethanol, and methanol). In addition to the well-known difference of the emission efficiency according to the solvent, we found their time variation depending on the solvent. From the discussion based on the solubility of the capping organic ligand, hexadecylamine (HDA), to each solvent it is suggested that the observed time variation is caused by the liquation of the capping molecules form the dot surface and the resulting change of the number of the trap site for charges in the quantum dot.

Partially coherent beam is generated by imposing dynamic random phase to completely coherent beam. The coherence of partially coherent beam can be controlled by the randomness of random phase. The speckle pattern of the partially coherent beam passing through scattering medium is studied. The speckle pattern can be modulated into a bright focal spot by wavefront shaping. The influence of the coherence on the focusing is investigated.

High energy nanosecond vortex beams and cylindrically polarized beams are generated in Nd:YAG amplifiers. Vortex seed beams and cylindrically polarized seed beams are converted from a conventional Nd:YAG laser by spiral phase plate and polarization converter, respectively. Maximum output energy of optical vortex up to 995 mJ and cylindrically polarized beams up to 772 mJ have been achieved at 10 Hz in a 10-ns pulse, respectively. The amplification efficiency, the beam quality and pulse width of the amplification output are studied. Both the topological charge of the vortex seed beams and polarization state of cylindrically polarized beams are confirmed to be conserved during the amplification. The generation of high energy vortex beams and cylindrically polarized beams would be beneficial to laser material processing.

Previously, we have established hole-patterned liquid crystal (LC) lens consisted of a floating ring electrode (FRE LC lens). However, while the applied voltage is given across the FRE LC lens, the disclination lines are induced as conventional hole-patterned LC lens, degrading the lens quality. To avoid the appearrance of disclination lines, the polymer stabilization is adopted to construct the FRE LC lens. The polymer stabilized FRE LC lens not only excludes the occurrence of the disclination lines during applied voltages but also preserves optical properties similar to the ordinary FRE LC lens.

A prism compressor can compensate dispersion of femtosecond light pulses travelling in air for laser ranging. An accurate expression of the group delay dispersion (GDD) of a prism compressor at arbitrary incident angle and at arbitrary incident point is obtained, which is of benefit to finely compensating dispersion of femtosecond pulses. Influences of several parameters on group delay dispersion are analyzed for the active compensation of dispersion of femtosecond pulses. These expressions are convenient to applications of intra- and extra-cavity dispersion compensation of ultra-short laser pulses, as well as fine compensation of satellite laser ranging and laser altimetry.

Octahedral Au-core Pt-shell (Au@Pt) nanoparticles were successfully prepared via a galvanic replacement of Cu monolayer underpotentially deposited on Au core with a Pt monolayer. The visible light irradiation to Au@Pt nanoparticles-immobilized electrodes enlarged a cathodic current of oxygen reduction reaction (ORR), suggesting that the electrocatalytic activity of Pt shell layer was enhanced by the photoexcitation of localized surface plasmon resonance peak of octahedral Au-core particles.

We have produced superconducting sub-micron particles by laser ablation in superfluid helium and trapped them using quadrupole magnetic field due to the diamagnetism.