Projecting extended optical traps with shape-phase holography

Roichman, Yohai; Grier, David G.

doi:10.1364/ol.31.001675

Cited by 61 publications

(73 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…An alternate phase pattern imprinted on unassigned pixels is used to divert excess light away from the intended trapping pattern. How the SLM plane is divided into assigned and unassigned domains can be tuned to minimize artifacts, improve diffraction efficiency, and optimize accuracy [2,3,4]. The images in Figs.…”

Section: Creating Optical Traps With Phase Gradientsmentioning

confidence: 99%

“…We demonstrate and characterize phase-gradient forces using the optimized holographic optical trapping technique [5,6,21] and shape-phase holography [2,4] to create extended optical traps with specified profiles for both their intensity and phase. Our apparatus, shown schematically in Fig.…”

Section: Creating Optical Traps With Phase Gradientsmentioning

confidence: 99%

“…We demonstrate theoretically and confirm experimentally that OAM-induced torque is a special case of a general class of forces arising from phase gradients in beams of light. We also demonstrate that phase-gradient forces are generically non-conservative, and combine them with the conservative forces exerted by intensity gradients to create novel optical traps with structured force profiles.Our experimental demonstrations of phase-gradient forces make use of extended optical traps created through shape-phase holography [2,3,4] in an optimized [5] holographic optical trapping [6,7] system. Holographically sculpted intensity gradients enable these generalized optical tweezers [8] to confine micrometer-scale colloidal particles to one-dimensional curves embedded in three dimensions.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Optical Forces Arising from Phase Gradients

et al. 2008

Self Cite

View full text Add to dashboard Cite

We demonstrate both theoretically and experimentally that gradients in the phase of a light field exert forces on illuminated objects, including forces transverse to the direction of propagation. This effect generalizes the notion of the photon orbital angular momentum carried by helical beams of light. We further demonstrate that these forces generally violate conservation of energy, and briefly discuss some ramifications of their non-conservativity.Light's ability to exert forces has been recognized since Kepler's De Cometis of 1619 described the deflection of comet tails by the sun's rays. Maxwell demonstrated that the momentum flux in a beam of light is proportional to the intensity and can be transferred to illuminated objects, resulting in radiation pressure that pushes objects along the direction of propagation. This axial force has been distinguished from the transverse torque exerted by helical beams of light carrying orbital angular momentum (OAM) [1]. We demonstrate theoretically and confirm experimentally that OAM-induced torque is a special case of a general class of forces arising from phase gradients in beams of light. We also demonstrate that phase-gradient forces are generically non-conservative, and combine them with the conservative forces exerted by intensity gradients to create novel optical traps with structured force profiles.Our experimental demonstrations of phase-gradient forces make use of extended optical traps created through shape-phase holography [2,3,4] in an optimized [5] holographic optical trapping [6,7] system. Holographically sculpted intensity gradients enable these generalized optical tweezers [8] to confine micrometer-scale colloidal particles to one-dimensional curves embedded in three dimensions. Independent control over the intensity and phase profiles along the curve then provide an ideal model system for characterizing the forces generated by phase gradients in beams of light. OPTICAL FORCES DUE TO PHASE GRADIENTSThe vector potential describing a beam of light of frequency ω and polarizationε may be written in the form A(r, t) = A(r) exp (i ωt)ε.(1)Assuming uniform polarization (and therefore a form of the paraxial approximation), the spatial dependence,is characterized by a non-negative real-valued amplitude, u(r), and a real-valued phase Φ(r). For a plane wave propagating in theẑ direction, Φ(r) = −kz, where k = n m ω/c is the light's wavenumber, c is the speed of light in vacuum, and n m is the refractive index of the medium. Imposing a transverse phase profile ϕ(r) on the wavefronts of such a beam yields the more general formwhereẑ · ∇ϕ = 0 and where the the direction of the wavevector,now varies with position. The associated electric and magnetic fields are given in the Lorenz gauge by E(r, t) = − ∂A(r, t) ∂t and (5)where µ is the magnetic permeability of the medium, which we assume to be linear and isotropic. Following the commonly accepted Abraham formulation [9], the momentum flux carried by the beam iswhere I(r) = u 2 (r) is the light's intensity, and where w...

show abstract

Section: Creating Optical Traps With Phase Gradientsmentioning

confidence: 99%

Section: Creating Optical Traps With Phase Gradientsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Optical Forces Arising from Phase Gradients

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…We have been so far unable to isolate and eliminate this optical tilt with the limited degrees of freedom of our optical train. We suppose that in a holographically generated LOT, 14 it would be straightforward to null both aberrations and tilt by modifying the computed hologram. 21 If this source of error were eliminated, it seems the remaining error due to centroiding could readily be reduced to the nanometer level by further increasing the optical magnification.…”

Section: Instrumental Resolutionmentioning

confidence: 99%

“…11 One-dimensional arrays of particles have also been trapped in the counterpropagating Gaussian beams of fiber optic traps. 12 Recently, similar, unscanned circular and clover-leaf shaped traps 13 and uniform line optical traps 14 have been formed using holographic optical tweezers ͑HOT͒ methods.…”

Section: Introductionmentioning

confidence: 99%

Line optical tweezers instrument for measuring nanoscale interactions and kinetics

Biancaniello

Crocker

2006

Review of Scientific Instruments

View full text Add to dashboard Cite

We describe an optical tweezers instrument for measuring short-ranged colloidal interactions, based on a combination of a continuous wave line optical tweezers, high speed video microscopy, and laser illumination. Our implementation can measure the separation of two nearly contacting microspheres to better than 4 nm at rates in excess of 10 kHz. A simple image analysis algorithm allows us to sensibly remove effects from diffraction blurring and microsphere image overlap for separations ranging from contact to at least 100 nm. The result is a versatile instrument for measuring steric, chemical and single-molecular interactions and dynamics, with a force resolution significantly better than achievable with current atomic force microscopy. We demonstrate the effectiveness of the instrument with measurements of the pair interactions and dynamics of microspheres in the presence of transient molecular bridges of DNA or surfactant micelles. We describe an optical tweezers instrument for measuring short-ranged colloidal interactions, based on a combination of a continuous wave line optical tweezers, high speed video microscopy, and laser illumination. Our implementation can measure the separation of two nearly contacting microspheres to better than 4 nm at rates in excess of 10 kHz. A simple image analysis algorithm allows us to sensibly remove effects from diffraction blurring and microsphere image overlap for separations ranging from contact to at least 100 nm. The result is a versatile instrument for measuring steric, chemical and single-molecular interactions and dynamics, with a force resolution significantly better than achievable with current atomic force microscopy. We demonstrate the effectiveness of the instrument with measurements of the pair interactions and dynamics of microspheres in the presence of transient molecular bridges of DNA or surfactant micelles.

show abstract

Advanced optical trapping by complex beam shaping

Woerdemann

Alpmann

Esseling

et al. 2013

Laser & Photonics Reviews

348

205

View full text Add to dashboard Cite

Optical tweezers, a simple and robust implementation of optical micromanipulation technologies, have become a standard tool in biological, medical and physics research laboratories. Recently, with the utilization of holographic beam shaping techniques, more sophisticated trapping configurations have been realized to overcome current challenges in applications. Holographically generated higher‐order light modes, for example, can induce highly structured and ordered three‐dimensional optical potential landscapes with promising applications in optically guided assembly, transfer of orbital angular momentum, or acceleration of particles along defined trajectories. The non‐diffracting property of particular light modes enables the optical manipulation in multiple planes or the creation of axially extended particle structures. Alongside with these concepts which rely on direct interaction of the light field with particles, two promising adjacent approaches tackle fundamental limitations by utilizing non‐optical forces which are, however, induced by optical light fields. Optoelectronic tweezers take advantage of dielectrophoretic forces for adaptive and flexible, massively parallel trapping. Photophoretic trapping makes use of thermal forces and by this means is perfectly suited for trapping absorbing particles. Hence the possibility to tailor light fields holographically, combined with the complementary dielectrophoretic and photophoretic trapping provides a holistic approach to the majority of optical micromanipulation scenarios.

show abstract

Projecting extended optical traps with shape-phase holography

Cited by 61 publications

References 26 publications

Optical Forces Arising from Phase Gradients

Optical Forces Arising from Phase Gradients

Line optical tweezers instrument for measuring nanoscale interactions and kinetics

Advanced optical trapping by complex beam shaping

Contact Info

Product

Resources

About