This PDF file contains the front matter associated with SPIE Proceedings Volume 10712, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

We elucidated femtosecond laser trapping dynamics of Rayleigh particles by modifying the surface property of nanoparticles and changing the viscosity. Through bright field, dark field and backscattering images, we monitored ejection behavior of nanoparticles which takes place in the direction perpendicular to laser polarization and switched from one side to the other. For very hydrophobic nanoparticle, we succeeded in observing directly a transient assembly and confirmed that its formation is responsible to the directional ejection. Also the trapping dynamics was compared for femtosecond and continuous-wave lasers in highly viscous solvent, which gives a new viewpoint for understanding femtosecond laser trapping mechanism.

Three-dimensional super-resolution microscopy based on fluorescence depletion (3D-SRM) was applied to the observation of immunostained microtubules having complicated structures stacking each other. Owing to a high depth resolution overcoming the diffraction limit, we can observe the tubulin fibers intertwined in a cell with improved image quality. Since the 3D-SRM system can be setup by adopting a simple two-color annular wave plate (TAWP) to a commercial laser scanning microscope (LSM), 3D-SRM is expected to be a powerful measurement method in life science.

AMPA-type glutamate receptor (AMPAR) is one of the major neurotransmitter receptors at excitatory synapses. The initial assembling states of AMPARs at cell surface are essential for synaptic transmission, which is related with learning and memory in living neural systems. To realize artificial control of synaptic transmission, we demonstrate to modulate the initial assembling states of quantum-dot conjugated AMPARs (QD-AMPARs) with optical trapping. The optical trapping dynamics of QD-AMPARs on living neurons was evaluated with fluorescence imaging and fluorescence correlation spectroscopy (FCS). The transit time at laser focus of QD-AMPARs on neurons estimated from FCS analysis increased with the culturing days and addition of neurotransmitter, which suggests that QD-AMPARs are confined at the focal spot due to optical trapping.

We developed a method to collect micro- and nano-vesicles on a glass substrate using the optical pressure of a laser beam. The laser beam was focused on the glass substrate which sandwiches a suspension containing micro- or nano-sized vesicles prepared by a phospholipid. The optical pressure generated at the interface of the medium and the vesicles accelerated the vesicles to form aggregates on the glass surface. Two types of glass substrates, hydrophilic and aminated ones, showed no difference in the adsorption property of the vesicles. Time to be required for collecting a certain amount of the vesicles was inversely proportional to the concentration of the vesicles. To enhance the collection efficiency, gold nanoparticles were added to the suspension of the vesicles. We found that gold nanoparticles reduced the collection time as short as 1/10-times.

We report stable and reproducible trapping of different micro and nanoparticles using a far field dual fiber tip optical tweezers. The tweezers properties are analyzed by studying the trapped particles residual Brownian motion. The trapping potential is harmonic and the trapping forces in transverse direction are typically three times larger with respect to axial direction. Interference fringe trapping is observed for 300 nm YAG particles. Depending on their length, NaYF4 nanorods are trapped in single or dual fiber tip configurations. Longest rods could be trapped with one single fiber tip at 5 μm away from tip. The experimental results are discussed using numerical simulations based on exact Maxwell Stress Tensor approach.

Optical microscopy has been a tool of choice ever since van Leeuwenhoek used Hooke's microscope to observe biological specimens. Chief among its advantages is the fact that imaging is noninvasive. In combination with the straightforward sample preparation and general convenience, optical microscopes remain essential to many aspects of modern-day research.

A tightly focused laser beam exerts optical force on nanoparticles dispersed in an aqueous solution, leading to an optical trapping of them at the focal point. Recently, we have developed plasmonic optical tweezers for soft nano-matters such as DNA, thermoresponsive polymer chains, and dye aggregates. We observed the interested trapping behaviors of the soft nanomaterials on such liquid-solid interfaces. Our attention is paid to such optical trapping of them on interfaces because optical force strongly depends on the dielectric constant of the surrounding medium. In the present study, we demonstrated that optical trapping of quantum dots and octahedral gold nanocrystals at water-oil interface. Dark-field microscopy was a powerful tool to observe the trapping behaviors of the gold nanoparticles, while fluorescence microscopy was used for the observations of the quantum dots.

We experimentally demonstrated the manipulation and transportation of nano-diamonds with diameters of 50 nm using a thin tapered fiber. When a green laser was injected from one side of the fiber and a near-infrared laser was also injected from the opposite side, nano-diamonds could be stopped on the fiber. When the balanced power for stopping nanodiamonds, we confirmed that the balanced powers were clearly different for fluorescent and non-fluorescent nanodiamonds and that for fluorescent nano-diamonds was smaller than non-fluorescent ones, which could be responsible for the difference in absorption. This result suggested the possibility that the macroscopic motion of nano-materials could be controlled based on their resonant absorption property.

The exploitation of single objective lens for both trapping and imaging in standard optical trapping system confines the trapping and imaging planes to the focal plane, which hinders the development of optical trapping along axial direction. To break the limitation, we develop an axial-plane optical trapping and imaging setup and demonstrated simultaneous trapping and imaging in axial plane. A modified Gerchberg-Saxton iterative algorithm based on axial-plane Fourier transform is proposed for direct shaping of novel optical traps in axial plane. With the combination of the proposed algorithm and the axial-plane imaging technique, axial-plane holographic optical tweezers is demonstrated and parallel calibration of multiple traps along axial direction is realized. The proposed technique also provides direct visualization of the trapped particles for study on trap performance of various optical fields, including Bessel beams, Airy beams and snake beams.

Optical tweezers have played a significant role in the advancement of micro-manipulation. However, optically trappable objects are limited to a certain size and material range. To overcome these constraints, we propose a noncontact micro-manipulation technique, which uses optically trapped particles to locally manipulate the surrounding fluid and thus freely diffusing particles within it. We show that our method can be used to successfully suppress both translational and rotational Brownian motion of a free-floating object, using hydrodynamic interactions alone, in an easily reconfigurable setup.

We have experimentally demonstrated remote plasmonic optical trapping on a chemically-synthesized silver nanowire (AgNW) induced by nonlinear optical effects, i.e. sum-frequency generation (SFG) and four wave-mixing (FWM). AgNWs were spin coated on a clean cover slip, and then covered with quantum dot (QD) aqueous solution. Two femtosecond IR laser pulses having different energies were focused on one end of the AgNW. SFG and FWM signal was observed at not only the excitation spot but also another end of AgNW through launching propagating plasmon modes. As results, it was found that QDs were trapped on the AgNW when two pulses were overlapped in time. QD resonance wavelength dependence on the trapping behavior indicates that trapping site on AgNW can be controlled.

Optical trapping and manipulation using focused laser beams has emerged as a powerful tool in the biological and physical sciences. However, scaling this technique to nanoparticles remains challenging. In this work, we propose a novel strategy to optically trap nanoparticles even under the most challenging situation using engineered optical field. The distribution of the optical forces can be tailored through optimizing the spatial distribution of a vectorial optical illumination to favor the stable trapping of a variety of nanoparticles. It is shown that the proposed optical tweezers has the ability of supporting stable three-dimensional trapping for nanoparticles while avoiding trap destabilization due to optical overheating. Besides, the interaction between the angular momentum of the light and the nanoparticle is also explored to control the movement behavior of the nanoparticle. The technique presented in this work offers a versatile solution for trapping nanoparticles and may open up new avenues for optical manipulation.

Photoisomerization induced molecular motion in azo polymers is an area of research that witnessed intensive studies owing to its potential in optical manipulation. In this paper, we give an overview of the theory of matter motion induced by photoisomerization. We show that besides photoisomerization, a gradient of light intensity is necessary to generate motion; e.g. generate a photoisomerization force to move matter. In concept, matter motion is due to competing forces, including viscous and photoisomerization forces, and possible radiation pressure and elastic forces, as well as a random force due to thermal fluctuations. In solid films of azo-polymers, the photoisomerization force overcomes other forces due to softening and decrease of viscosity of the material by photoisomerization.

We discover that 1.06 μm picosecond vortex pulses induce chiral mass-transport to form a single-armed chiral surface relief in azo-polymer through two photon absorption process. The surface relief exhibits a diameter of a 2.5μm, i.e. 0.7 times of diffraction limit.

We found that plasmonic optical trapping of soft nanomaterials were driven not only by an enhanced optical force but also by thermophoretic force. Since thermophoresis exerted on the nanomaterials strongly depends on their size and the surrounding medium, it is potentially applicable for a manipulation method of nanomaterials. In the present study, by taking advantage of the thermophoresis, we demonstrated thermophoresis-assisted optical trapping of pyrene-labeled hydrophilic polymer chains on plasmonic nanostructures.

We demonstrate a self-written sub-millimeter (>300 μm) helical fiber in a photo-cure resin by irradiation of non-diffractive 1^st-order Bessel beam with an orbital angular momentum. The twisted direction of the helical fiber can be controlled by only reversing the sign of the topological charge of Bessel beam.

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

We have reported that laser-induced metal particle migration in glass. Laser illumination heated a metal particle in glass. The surrounding glass of the metal particle was also heated and softened; hence, the metal particle migrated in the glass. The temperature gradient caused the driving force. The interfacial tension between the glass and the metal particle was varied by the temperature. The temperature nonuniformity caused the interfacial tension nonuniformity and metal particle migration. In this presentation, we demonstrated metal particle migration by the surface heating of the glass with a CO₂ laser. Heating of glass surface moved metal particle located 200 μm below the surface. The particle was moved out of the glass after 400 s illumination. The migration speed was 0.3~0.7 μm/s.

We present the new structured materials, i.e. string-shaped Au nano-structures, formed by employing the optical vortex ablation processing on an Au thin film. We also address the filament formation of Au particles by deposition of optical vortex pulse. Such structured Au particles have the potential to pave the pathway towards advanced chemical reaction.

We fabricated semiconductor cadmium selenide (CdSe) quantum dots via the pulsed laser ablation in the superfluid helium. The fabricated quantum dots showed blue-shifted fluorescence due to the strong quantum confinement effect. The fluorescence blinking phenomena were also observed indicating the single photon emission process. Our proposed scheme is a simple, robust, and reliable method to fabricate quantum dots and to introduce the highly fluorescence nanoparticles into superfluid helium appropriate for resonant optical manipulation and nano-tracers for liquid helium visualization.

We first demonstrated the generation of an optical bottle beam with a zero-intensity region surrounded by threedimensional bright regions from an intra-cavity frequency-doubled Nd:YVO4 laser with a nearly hemispherical cavity configuration. We also numerically analyzed the components of the generated bottle beam which consists of a series of Laguerre–Gaussian modes. The experimental results can be excellently reconstructed with the theoretical model.

We demonstrated direct surface-emitting of Laguerre–Gaussian beams with wavefront modulated lasers. This integrable phase-modulating surface-emitting lasers has potential to emit arbitrarily configured beam patterns without requiring any optical elements or scanning devices. The fabricated devices are on-chip-sized, making them suitable for integration. We introduce a phase-modulating resonator in a semiconductor laser, which analogically behaves as phaseonly holograms, kinoform, to allow the concurrent realization of lasing and phase modulation. Particularly, this is promising in the use for free-space optical communications due to the fact that coaxial propagation of orbital angular momentum (OAM) properties with different OAM mode states are mutually orthogonal.

Theoretical wave functions are analytically derived to formulate the propagation evolution of the Hermite-Gaussian (HG) beams transformed by single lens astigmatic mode converter with arbitrary angle. The derived wave functions are associated with the combination of the rotation transform and the antisymmetric fractional Fourier transform. The derived formula are validated by the mode conversions of high-order HG beams generated by an off-axis diode-pumped solidstate laser. In addition to validation, the creation and evolution of vortex structures in the transformed HG beams are numerically manifested. The present theoretical model can be applied not only to characterize the evolution of the transformed beams but to design the optical vortex beams with various forms.

Anharmonic behavior of coincidence count rate obtained with the hologram shifting method can be used to probe highdimensional effect of orbital angular momentum entangled photon pairs. We perform numerical analysis for the case where the photon pairs are created by spontaneous parametric downconversion, and both photons are observed through singlemode fibers after mode conversion with phase-only holograms. The center of the holograms are shifted by a constant distance from the beam axis and the relative shift direction is scanned. We explore effects of pump beam width and crystal length with respect to the hologram shift distance.

Off-axis pumped Nd:YAG/Cr⁴⁺:YAG lasers under degenerate cavity conditions are explored to achieve high-pulseenergy geometric modes for beam transformation. The employment of Nd:YAG crystal promises efficient passively Qswitched (PQS) operation with a flexible cavity length to ensure various PQS geometric modes with stable structures can be generated. It is experimentally confirmed that the output energy and peak power of the PQS geometric modes can easily reach up to over 100 μJ and 10 kW with fairly stable pulse trains in pure linear polarization. Various high-energy vortex beams carrying large angular momentum and diverse phase structures are achieved by converting the planar geometric modes into the circular ones to offer promising light sources for potential applications.

Optical beams with Orbital Angular Momentum (OAM) can potentially be used to probe forbidden transitions. However, the size of the vortex beam has to be comparable to that of an atom, molecule or an artificial atom. We propose and demonstrate a de-magnifying hyperlens allowing reducing the size of the vortex beam to the nanometer scale.

We have demonstrated a nano-particle rotation above a plasmon-resonant gold multimer nano-structures with a nano-gap and a circularly polarized laser. We have confirmed that the rotational direction depends on the number of triangle nano-structure. And the multiple position trapping has been realized with a control of triangle nano-structure.

Launching and control of graphene plasmon are crucial for nanodevice applications. To achieve that, previous studies used foreign object and/or angled illumination to provide plasmon launching and directional control. In this study, we considered graphene nanoridges, which is a defect-free natural structure of graphene to launch plasmon, using analytic method and simulation. The result shows that a single graphene nanoridge can launch plasmon, with an interesting relationship between the SPP amplitude and ridge physical curve length. By using two nanoridges with different size, the interference between SPP wave launch from each ridge result in right-left asymmetric plasmon launching. With the proper size and separation, unidirectional, bidirectional, or wavelength-sorted plasmon launching can be achieved.

A laser-induced micro-bubble and fluid flow can assemble dispersoids locally and rapidly by CW laser illumination to light absorptive materials in a suspension. However, the control method of such a process hasn’t been well established. In this study, we tried to construct a quantitative analysis method based on the projection area of the assembled dispersoids and to clarify the factors for the control of the laser-induced assembly. As a result, it was clarified that adsorption of the amphiphile onto gas-liquid interface of the bubble/suspension plays an important role for the controllability. Particularly, we found that there is a high correlation between the projection area of the assembled dispersoids and its concentration under the controlled assembly. These findings are crucial not only for the control of the laser-induced assembly but also for the rapid concentration measurement techniques.

We investigate motion of particle pairs optically bound in tractor beam. The tractor beam can exert a negative force on a scatterer, in contrast to the pushing force associated with radiation pressure, which can pull the scatterer towards the light source. The particle movements can be enhanced by long-range interaction between illuminated objects, called optical binding. We study optical binding of two micro-particles in various geometrical configurations and investigate their motional behaviour in tractor beam. We demonstrate that motion of two optically bound objects strongly depends on their mutual distance and spatial orientation. Such configuration-dependent optical forces add an extra flexibility to our ability to control matter with light. Understanding these interactions opens the door to new applications involving the sorting or delivery of colloidal self-organized structures.

We present a few of our recent theoretical and experimental results related to the behavior of micron-scale particles placed into nonlinear optical potentials. The two-dimensional optical ratchet can rectify motion of Brownian particles in any direction in the plane and unstable cubic optical potential results in noise-induced particle motion. Action of optical spin-force was demonstrated in a novel geometry where it is responsible for particle orbiting.

Various optical properties originated from the surface plasmon resonance have been much studied, as the example of extraordinary optical transmission (EOT) arising in the metallic thin film with a nano-hole array (NHA). In the analytical chemistry, these phenomena can be applied to the sensors for viruses and bacteria based on the peak shift caused by the change in surrounding refractive index. We have clarified that the amount of EOT peak shift can be enhanced by designing the surface structure of NHA with the random nano-spikes. The results indicate the two cases that the peak shift is enhanced with and without the EOT, which leads to the understanding of the applicable range of random NHA design.

An experimental study of the nonlinear self-action of Bloch surface waves (BSWs) is reported. The BSWs are excited by a continuous-wave diode laser at the interface between a one-dimensional photonic crystal and a water suspension of 50-nm polystyrene particles, as revealed by the angular reflectance spectrum. Redistribution of the particles under the action of the gradient optical forces leads to a significant modification of the BSW resonance curve at an incident power as low as 14 mW. The results highlight that nanosuspensions can be used as artificial Kerr media to perform model experiments on the optical switching of surface waves.

We investigated resonant light scattering properties of single wavelength-scale metallic or dielectric nanorods in the energy-momentum space. High-refractive-index silicon nanostructures supporting strong Mie resonances allow light manipulation beyond the optical diffraction limit. Based on dark-field microscopy and numerical modal analysis, we revealed that the waveguide dispersion of the silicon nanorod determines and controls the resonant scattering properties. We also demonstrated for the first time quantitative measurement of the differential far-field scattering cross-section of a single metal nanostructure over the full hemisphere. While conventional back-focal-plane imaging suffers from optical aberration/distortion and numerical aperture limit of the objective lens, goniometer-based direct solid angle scanning provides quantitative and flawless information of far-field scattering from nanostructures on the wavelength scale or less.

Chiral nanostructures exhibiting circular dichroism (CD) activities absorb different amounts of left- (LCP) and righthanded circularly polarized (RCP) light. Here, we report the observation of dissymmetry between two-photon-induced LCP and RCP photoluminescence (TPIPL) from two-dimensional (2D) chiral plasmonic nanostructures. Under linearly polarized ultrashort pulse irradiation with a low input power of 3 mW, the excited multipolar responses of the 2D chiral nanostructure yield circularly polarized TPIPL. The handedness of the circularly polarized TPIPL was dependent on the handedness of the chiral nanostructure. The chiral nature of TPIPL may find potential applications in sensing of chiral molecules and materials.

We report a development of microscopic size gradient index vortex masks using modified stack-and-draw technique. Vortex mask has a form of tens of microns thick, flat-surface all-glass plate. Its functionality is determined by internal nanostructure composed of two types of soft glass nanorods. Their spatial arrangement ensures that the average refractive index mimics continuous refractive index distribution imposing azimuthal phase modulation of optical beam. The mask of thickness of 40 microns is used to demonstrate generation of optical vortices with charges 1 and 2, in the femtosecond and cw regimes, respectively.

We study optical properties of the gradient index vortices obtained using effective medium approach. Vorteces with charge +1 has been was developed using two types of nanorods made of thermally matched low and high refractive index glasses. Their optical properties of vortices are analyzed in the context of glass refractive index and size of the components. Consequently vortex has been integrated with single mode optical fiber and such a system is analyzed.

We study optical properties of gradient index vortex masks based on an effective medium approach. We consider masks with single charge developed using two types of nanorods made of thermally matched low and high refractive index glasses. Optical performance of generated vortices are analyzed in terms of glass refractive index difference and spatial dimension of the components. A fabricated vortex mask has been combined with single mode optical fiber. Optical performance of the resulting fiber integrated vortex mask is characterized and discussed.

In photoinduced force microscopy (PiFM), amplitude modulation techniques, such as direct mode, and heterodyne amplitude modulation techniques have been used to detect the photoinduced force. These amplitude modulation techniques are affected by other forces because the resonance frequency of a cantilever shifts and non-conservative force damp the cantilever motion. Here, we investigate and propose the heterodyne frequency modulation technique (heterodyne-FM) for reduction of the influence of the other forces and photothermal force. Heterodyne-FM PiFM enabled the acquisition of PiFM images and force spectra without those artifacts. Using the heterodyne-FM technique, we succeed to visualize and evaluate photoinduced force between a tip and a quantum dot on gold surface.

We investigate how an optical vortex radiation modulates magnetic spin order of a metallic chiral magnet. The optical vortex carries its intrinsic orbital angular momentum and has a toroidal field intensity, hence such a helical beam is expected to couple to angular momentum of electrons. Here we theoretically construct microscopic interactions between an optical vortex and electrons in the chiral magnet. As a result, we derive a spin-spin interaction which is induced by the optical vortex radiation in the one-dimensional tight-binding model, and find that this interaction can modulate the magnetic order. The optical vortex should be one of the plausible candidates for spin control source, and open a new door to future spintronics devices.

The process of remapping the intensity profile of a laser beam is presented. Bimorph deformable mirror was used to change the beam phase; the control signals for the mirror were calculated in accordance with both phase analysis and far-field intensity distribution measurements.

The optical property of plasmon-active metal nano dimer structure strongly depends on its shape and gap distance. Thus, the precise control of metal nano structure has been receiving much attention in various field. In the present study, we have tried to control the plasmonic property by combining electrochemical method with in-situ dark-field microscopy. Controlled metal dissolution in the size range below a few nm leads to the successful switching from the charge transfer plasmon (CTP) to the bonding dipolar plasmon (BDP) mode. The highly localized plasmonic field generated during the switching could be applied for various applications including molecular optical trapping in solution at room temperature.

When nanoparticles are exposed to an optical field with orbital angular momentum, that is optical vortex, such particles are swirled around optical axis. Although such a phenomenon was observed experimentally, theoretical and numerical approaches have not been developed enough. In this study, we propose a numerical model for dynamical motions of a single nanoparticle. Based on Rayleigh scattering regime, the gradient force which dominantly acts on a nanoparticle is computed. The gradient force is usually derived from time averaged electric field and then, a tangential component is vanished. Herein, we carefully treat the tangential term by using time dependent electromagnetic fields. Consequently, it is found that a tangential component in the gradient force induce swirling motions of a nanoparticle.

Abstracts A method, based on particle swarm optimization (PSO) and finite-difference time-domain (FDTD) simulation, is proposed to optimize micro-well structural parameter of SPRi sensor with polarization contrast modulation. According to PSO algorithm, these six structural parameters are optimized. Following that, the electromagnetic field characteristics of the gold micro-well structure involving the background gold film thickness are simulated and optimized by FDTD. It is proved that the sensitivity of the optimized structure is four times higher than the traditional one, which shows the practicability of the home-built SPRi sensor, in addition, as a result of the high signal-to-noise ratio, the refractive index resolution of the sensor is two order of the magnitude lower. Besides that, optimization algorithm provides a new way for other SPR sensor optimization.

Invoking Maxwell’s classical electrodynamics in conjunction with expressions for the electromagnetic (EM) energy, momentum, force, and torque, we use a few simple examples to demonstrate the nature of linear and angular momentum exchange between a wave-packet and a small spherical particle. The linear and angular momenta of the EM field, when absorbed by the particle, will be seen to elicit different responses from the particle.

Coherent measurement of orbital angular momentum (OAM) spectrum of light fields plays a key role in many important applications, such as OAM-based multiplexing in optical communications. The existing methods for measuring the OAM spectrum by spatially separating OAM components or interferometric technique suffer from poor efficiency and interferometric stability requirements. Here, we propose a novel technique to measure the OAM spectrum of light fields in a single shot manner by exploiting a scattering optical element. Our technique enables to directly extract the OAM spectrum from a recorded single-shot speckle pattern using algorithms based on the speckle-correlation scattering matrix and spatial mode decomposition method. As a proof of concept, we built a robust measurement system based on a fast digital micromirror device to demonstrate the feasibility of the proposed technique.

We propose polarization control system based on graphene-dielectric multilayer stacking arrays and numerically investigate the characteristics of transmission spectrum and phase shift. The results show a high extinction ratio polarizer, and the operating frequency of which can be designed via changing the geometric parameters and Fermi level. In addition, a large phase difference is generated in the x and y directions, and polarization control can be achieved by the superposition of the two modes along the orthogonal directions. The proposed structure demonstrates excellent polarization manipulation capability, ultrathin thickness and flexible control of the operating frequency, providing a good avenue for integration of device in the infrared.

The generations of photonic jet array using rectangle phase diffraction grating at visible light region are demonstrated numerically and experimentally for the first time. The power flow patterns for the rectangle diffraction grating are simulated by using the finite-difference time-domain method. In experiment, the rectangle phase diffraction grating was fabricated with polydimethylsiloxane material. The direct imaging of the spatial and amplitude features for the gratingassisted photonic jet array is performed with a scanning optical microscope system. The focusing qualities of photonic jet array are evaluated in terms of focal length and transversal width along propagation and transversal directions. The photonic jet array could be operated in a wide range application for nanotechnology, self-assembly, energy generation and storage materials through the rectangle phase diffraction grating.

To realize optical manipulation and measurement for isolated quantum dots (QDs) in gaseous phase, we are developing experimental apparatus for dispersing QDs into a gas by using droplets of organic solvents. The droplet was generated with a nebulizer using a piezoelectric element and was monitored by observing the scattered light. The time variation of the QD density was also monitored by observing the fluorescence from the QDs. In the case of the diethyl ether solution of CdSe/ZnS core-shell type QDs, it was confirmed that the evaporation of the droplet was enhanced with a liquid-nitrogen trap and its typical lifetime was roughly 30 s, which was considered to be determined from the descent by the force of the gravity, the evaporation, and the diffusion.

Utilizing three unique defining properties of volume holograms, namely, wavelength degeneracy, angular selectivity, and multiplexing capability, here we show the recording and simultaneous reconstruction of the Airy and Dual Airy beam from multiplexed volume holographic gratings (MVHGs). Each grating acts independently and creates its own diffraction pattern corresponding to the shape of the grating. Multicolor reconstruction of MVHGs are shown. Experimental results demonstrate that volume holograms are capable of reproducing optical wavefront with high precision without affecting the structural properties of beams at any optical wavelengths. These MGHGs acts as wavelength-independent mode shaper and can be used to make compact optical systems. The volume hologram based beam shaping technique is simple and cost-effective and has potential for the mass production.

The unimorph deformable mirror (DM) is favored in the field of synchrotron radiation due to its simple structure, dynamic surface figure and adaptive adjustment. The request of mirror surface accuracy on the synchrotron radiation beam focus can be up to sub-nanometer RMS. Ion beam figuring is a high precision processing method with noncontacting and roughness damage. However, because it belongs to the type of thermal manufacturing, the adhesive layer characteristic is changed and the DM’s figuring accuracy is reduced by the thermal deformation. In this paper, thermal simulation and temperature test of the adhesive during ion beam processing are carried out; The variation law of temperature and thermal stress of the adhesive layer with different ion beam diaphragms and scanning times are obtained. Therefore, the selective guideline for the diaphragm is obtained. With the optimal process parameters, the temperature of the adhesive layer is decreased with the minimum temperature between the glass transition temperature Tg and 1/2 of the Curie temperature Tc.

Semiconductor quantum dots (QDs) composed of ZnTe-AgInTe2 solid solution ((AgIn)_xZn_2(1-x)Te₂, ZAITe) were synthesized by a thermal reaction of corresponding metal acetates and a Te precursor in 1-dodecanethiol. TEM observations revealed that rod-shaped QDs with width of ca. 4 nm and length of ca. 16 nm were formed regardless of chemical composition of particles, x value. The absorption onset and the band-edge PL peak energy were enlarged from 1.13 to 1.53 eV and from 1.23 eV to 1.53 eV, respectively, with a decrease in x from 1.0 to 0.25. The observed optical properties of ZAITe QDs were largely tunable in the near-IR region , being suitable for optical applications.

Manipulating single cell with optical tweezers in vitro or in vivo plays an important role in biological research, whereas the manipulation of individual cells might be affected by the neighbor cells especially in the crowd environment. To overcome this problem, an annular beam formed by the far-field Bessel beam is introduced to serve as an optical shield to protect the target cells from being disturbed. We demonstrate that an individual cell can be trapped and manipulated through the crowd cells. What’s more, the interaction between two cells can be investigated by using a dual-trap optical tweezers in the crowd environment with the help of the optical shield.

Shaping complex fields with a digital micromirror device (DMD) has attracted much attention recently due to its potential application in optical communication and microscopy. In this paper, we present an optimized Lee method to achieve dynamic shaping of orbital-angular-momentum (OAM) beams using a binary DMD. An error diffusion algorithm is introduced to enhance the accuracy for binary-amplitude hologram design, making it possible to achieve high fidelity wavefront shaping while retaining a high resolution. As a proof of concept, we apply this method to create different classes of OAM beams and experimentally demonstrate the dynamic shaping of different OAM beams including pure modes and mixed modes with a switching rate of up to 17.8 kHz.

We theoretically study the optical selective transport of nanoparticles with electronic resonance levels using counterpropagating laser beams. In our previous work, we suggested the possibility of selective transport of nanoparticles with electronic resonance levels by using the corresponding resonant light. However, such transporting is difficult when the contribution of the background dielectric constant is much larger than that of the electric resonance. Even in such situation, the selective transport is possible if we use counter-propagating laser beams. We show this possibility by the calculation of exerted force on nanoparticles and Brownian dynamics analysis.

The principle of optical trapping is conventionally based on the interaction of optical fields with linear-induced polarizations. However, the optical force originating from the nonlinear polarization becomes significant when nonlinear optical nanoparticles are trapped by femtosecond laser pulses. Herein we develop the time-averaged optical forces on a nonlinear optical nanoparticle using high-repetition-rate femtosecond laser pulses, based on the linear and nonlinear polarization effects. We investigate the characteristics of transverse and longitudinal optical forces for particles exhibiting self-focusing and defocusing effects. It is shown that the self-focusing effect increases the trapping force strength and improves the confinement of particles, whereas the self-defocusing effect leads to the splitting of potential well at the focal plane and destabilizes the optical trap, resulting in ejections of trapped particles along the direction of the beam’s propagation. The optical forces exerted on the nonlinear optical particles are experimentally related to the trapping stiffness. It is expected that the self-focusing (or self-defocusing) effect increases (or decreases) the trapping efficiency and stiffness. Our results successfully explain the reported experimental observations and provide theoretical support for capturing nonlinear nanoparticles with femtosecond laser trapping.

Here we demonstrated a GaN metalens array to project a light spots array which can be a light shape generator in the structure light applications. The advantages of this metadevice is light weight, small, ultrathin, durable and easy to compact with other device. The light spot size is a function with the distance of detector. A metalens array which arranged by the single metalens diameter is 20 μm projected a light spots array whose diameter of single light spot is 2.22 um in average at the distance is 150 cm far away and. Our design provides a new avenue for the structure light application such as distance sensing and 3D environmental construction.

We demonstrate here that control of local optical field near a single non-chiral gold nano-rectangle irradiated with linearly polarized light is possible from linearly polarized to nearly pure left- or right-handed circular polarization, by adjusting the angle of the incident polarization relative to the rectangle.

We demonstrate manipulation of nonlinear vibration of graphene mechanical resonator (G-MR) optically by photothermal effects of laser. Different photothermal effects are induced by combining of scattering light and different standing waves of light, which have different effects on nonlinear vibration. Experimental results indicate that nonlinearity is suppressed or promoted for each photothermal effects without almost changing its amplitude. These changes cannot be explained by conventional nonlinear vibration that the nonlinearity increases with increasing amplitude. To reveal the principle of the modulation, we proposed novel vibration model including photothermal effects in nonlinear vibration. Numerical calculation from the model well fits experimental results and revealed the principle. We believe that these technics of controlling nonlinear vibration open the further applications of G-MR.

Transition metal dichalcogenide such as MoS₂ is expected as high performance nano-electro-mechanical devices due to their unique electrical, optical and mechanical properties. One can expect that the combination of these properties are efficient to develop the novel functional devices. Here, we demonstrates the amplitude control of resonance characteristics of a cantilevered MoS₂ on the planar substrate, which is actuated by electrostatically. The AC and DC bias voltage dependences of the vibration amplitudes are well explained by the simplified model under linear elastic regime. Moreover, we demonstrate the optical manipulation of the vibration amplitude at the resonance. Under the irradiation of strongly absorbed light by MoS₂, the vibration amplitude is successfully manipulated by the laser intensity change.

Secure optical data links can be implemented using quantum communication (QC) protocols that offer physical-layer encryption without the mathematical complexity of traditional cryptography. Data encoding can be achieved using polarization entanglement and it is further proposed to obtain additional degrees of freedom for each single particle quantum state by using hyper-entanglement. For example, multiple carrier signals arriving at the same time can be assigned specific frequencies in the 100 GHz International Telecommunication Union (ITU) grid and be processed simultaneously by a receiver that uses a hyperspectral quantum optical circuit. In this paper, we address preservation of hyper-entanglement as the signals propagate through optical components of the quantum circuits and encounter their realistic properties.

We have studied plasmonic optical tweezers (POT) for nanomaterials such as DNA and polymers. These nanomaterials would be efficiently trapped by a plasmon-enhanced optical force. However, plasmon excitation also leads to a photothermal effect. Such heat generation has frequently hindered POT. Recently, we have developed a novel optical trapping technique; Nano-Structured Semi-Conductor-Assisted (NASSCA) optical tweezers. In NASSCA optical tweezers, we used a metal-free black silicon with a nanoneedles structure on the surface. NASSCA optical tweezers presents a useful and powerful manipulation technique without heat generation.

Poly(N-isopropylacrylamide) solution, which is a representative thermoresponsive polymer, exhibits a phase separation with a formation of polymer-rich microparticles due to dehydration and aggregation of the polymer chains above a lower critical solution temperature (LCST). However, little is known about the details of polymer concentration in the particle. We have developed optical tweezers combined with confocal Raman microspectroscopy to analyze a hydration structure in a single polymer rich particle. A focused near-infrared laser beam produced the microparticle at the focal point due to an optical force and a photothermal effect. In this study, we investigated that molecular weight dependence of the polymer concentration in the polymer-rich particle by means of Raman microspectroscopy.

Fluorescence correlation spectroscopy was applied to the evaluation of the local heating at the focal spot of nearinfrared laser for optical trapping. Based on the translational diffusion coefficient of probe dyes at the focal spot in solution, the relation between temperature rise and incident laser power, ΔT/ΔP, were determined for water, ethylene glycol, 1-pentanol, 1-hexanol, 1-octanol, 1-nonanol, and 1-decanol. The value of ΔT/ΔP linearly increased with a/l (a and l is the absorption coefficient and thermal conductivity of solvent, respectively) as predicted by a simple theoretical model.

Gold nanoparticles (Au NPs) exhibit strong light absorption due to localized surface plasmon resonance (LSPR), and efficiently convert light energy into heat under illumination. Heat transfer from Au NPs to surrounding matrices induces an increase in temperature, resulting in nanobubbles generation owing to explosive evaporation of the medium. In particular, stationary bubbles can be produced by illuminating CW laser for single Au NPs. These stationary bubbles in microscopic region drive fluid convection of medium and suggest the potential application to the manipulation of colloidal particles and molecules. In the present work, we have investigated the thermo-physical properties of the stationary bubbles and fluid convection of surrounding water by integrating experimental results with those by the theoretical calculation.

We have attempted to control molecular behavior of a small number of molecules which are strongly coupled with the localized light energy in the vicinity of the metal nano structures. The new hybridized state derived from the formation of the strong coupling state shows unique optical properties, so the active control of this has been attracting researches in various fields. At the present attempts, we have achieved controlling the LSP energy and the coupling strength of the coupling via electrochemical method. The electronic and vibrational states of organic dye molecules in strongly coupled with LSP has been investigated through electrochemical in-situ surface-enhanced Raman scattering (SERS) measurements, providing the vibrational and the electronic structure of molecule in the coupling state.

It is predicted by various theoretical studies that nanometer size molecules could be trapped in the strong electromagnetic field due to its steep spatial gradient of the filed intensity. In this study, we have attempted to observe the plasmonic molecular trapping behavior in the mixed solution of 4,4’-bipyridine and 2,2’-bipyridine by surface enhanced Raman scattering measurements. In order to control the molecular optical trapping selectivity, we have introduced the electrochemical potential control into the system. The experimental results would indicate the achievement of the selective control of molecular optical trapping at room temperature in solution.

A 100 micrometer sized hierarchical structure consisting of nanosheet can be obtained at the focus of laser beam in nanosheet colloid. This large sized structure was obtained from the colloidal liquid crystallinity of two-dimensional inorganic particles and laser radiation pressure. The scattering force of the laser beam converted the parallel nanosheet alignment to the direction of the incident laser beam. A giant tree-ring-like nanosheet texture is independent of the polarization direction, was organized at the periphery of the focal point.