Holographic techniques significantly extend the capabilities of laser tweezing, making possible extended trapping patterns for manipulating large numbers particles and volumes soft matter. We describe practical methods creating arbitrary configurations optical tweezers using computer-generated diffractive elements. While discussion focuses on ways to create planar arrays identical tweezers, approach can be generalized three-dimensional arrangements heterogeneous patterns.

High-temperature superconductors exhibit harmonic generation when immersed in an ac magnetic field. To explain this phenomenon, we propose a macroscopic critical-state model as alternative to the loop used by Jeffries et al. While original Bean of critical state only predicts odd harmonics, our extended also even harmonics taking into account dependence current upon The results measurements signals function field, dc temperature, and number are consistent with proposed model. In particular,...

We measure, in a single experiment, both the radiation pressure and torque due to wide variety of propagating acoustic vortex beams. The results validate, for first time directly, theoretically predicted ratio orbital angular momentum linear beam. experimentally determine this using simultaneous measurements levitation force on an absorber exerted by broad range helical ultrasonic beams produced 1000-element matrix transducer array. In general, with phase fronts have been shown contain as...

We discuss the application of spatial light modulators (SLMs) to field atom optics. show that SLMs may be used generate a wide variety optical potentials are useful for guiding and dipole trapping atoms. This functionality is demonstrated by production number different using single SLM device. These include Mach-Zender interferometer patterns generation bottle-beam. also current limitations in technology with regard both static dynamically deformed their use

JOHANNES Kepler is famous for discovering the laws of planetary motion, but he less well known writing what may have been first science-fiction story to involve space travel. During his observations, German astronomer noticed that tails comets always point away from Sun, which suggested Sun was exerting a sort radiant pressure. This led him in 1609 – year published propose sailing Earth Moon on light itself. Of course, and still stuff science fiction, 400 years later Kepler's initial ideas...

Negative radiation forces act opposite to the direction of propagation, or net momentum, a beam but have previously been challenging definitively demonstrate. We report an experimental acoustic tractor generated by ultrasonic array operating on macroscopic targets (>1 cm) demonstrate negative and map out regimes over which they dominate, we compare simulations. The result geometrically simple configuration show that effect is due nonconservative forces, produced redirection momentum flux...

Quantum ghost imaging uses photon pairs produced from parametric downconversion to enable an alternative method of image acquisition.Information either one the photons does not yield image, but can be obtained by harnessing correlations between them.Here we present examination resolution limits such systems.In both conventional and quantum is limited point-spread function optics associated with spatially resolving detector.However, whereas in systems only this point spread function, show...

Multiple low index particles (micrometer-sized ultrasound contrast agent), have been optically trapped using a 4 x Laguerre- Gaussian trap array. The trapping efficiency of the Laguerre-Gaussian arrangement was measured Stokes' flow approach whereby critical relative fluid velocity required to remove from optical measured. dependence on beam power also explored and optimum parameters were identified. Finally, utility array as selective filter demonstrated by tweezing multiple low-index...

To extend beyond the limited field of view associated with optical tweezers, we implement a new geometry for lensless trapping (“LOT”). A Ronchi ruling is imaged at sample interface critical angle total internal reflection imposing local structure upon fields. Due to resulting transverse gradients, more than one thousand microparticles spanning 1mm2 were organized into microchannels that are entirely in origin. generalized approach presented, allowing either guiding or stable trapping, as...

The temperature dependences of the transient photoinduced conductivity at different light levels in single crystals ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ and ultrathin (\ensuremath{\sim}40-\AA{}) epitaxial films ${\mathrm{DyBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ with fixed \ensuremath{\delta} are qualitatively quantitatively similar to those doping-induced oxygen...

As a step toward isolating the influence of modulated substrate potential on dynamics and phase transitions in two dimensions, we have studied behavior monolayer colloidal spheres driven by hydrodynamic forces into large array holographic optical tweezers. These traps constitute whose symmetry, separation, depth modulation can be varied independently. We describe particular set experiments, which invades pinning much as magnetic flux lines invade type II superconductors, including...

We demonstrate the use of a spatial light modulator (SLM) to facilitate trapping particles in three-dimensional structures through time-sharing. This method allows be held complex, configurations using cycling simple holograms. Importantly, we discuss limiting factors inherent current phase only SLM design for applications both optical tweezing and atom trapping.

Solid spheres, disks, and ellipsoids with micrometer-scale bipolar anisotropic character respond to external electric fields by aligning their mean optical axes parallel the field. The monodisperse, optically colloids (see Figure) are synthesized photopolymerization of a monodisperse liquid-crystal emulsion after mechanical deformation drops.

We synthesize, optically trap, and rotate individual nanovaterite crystals with a mean particle radius of 423 nm. Rotation rates up to 4.9 kHz in heavy water are recorded. Laser-induced heating due residual absorption the results superlinear behavior rotation rate as function trap power. A finite element method based on Navier–Stokes model for system allows us determine optical coefficient trapped particle. This is further confirmed by theoretical model. Our data show that translational...

Significance The emergence of “negative” frequencies in physical systems is often accompanied by intriguing consequences. For example, supersonic motion between a source and an observer leads to negative Doppler-shifted frequency, the meaning which time reversal received signal. To our knowledge, rotational analogue this situation—the consequences generating rotationally waves—has not been studied. Here we show, using acoustic source, that Doppler shift associated with handedness orbital...

Abstract Contactless sample confinement would enable a whole host of new studies in developmental biology and neuroscience, particular, when combined with long-term, wide-field optical imaging. To achieve this goal, we demonstrate contactless acoustic gradient force trap for light sheet microscopy. Our approach allows the integration real-time environmentally controlled experiments low photo-toxic imaging, which on variety marine animal embryos larvae. illustrate key advantages our approach,...

We describe optical trapping techniques based on holographic tweezer arrays useful for assembling colloidal particles into arbitrary arrangements photonics, optoelectronic, and sensor applications.

As normally used, no commercially available camera has a low-enough dark noise to directly produce video recordings of double-slit interference at the photon-by-photon level, because readout significantly contaminates or overwhelms signal. In this work, levels are reduced by turning on only when presence photon been heralded arrival, an independent detector, time-correlated produced via parametric down-conversion. This triggering scheme provides improvement required for direct imaging...

Researchers experimentally investigate the superluminal kinematics of scattering light sources through ultrafast time-resolved imaging.