Increasing trap stiffness with position clamping in holographic optical tweezers

Preece, Daryl; Bowman, Richard; Linnenberger, Anna; Gibson, Graham M.; Serati, Steven A.; Padgett, Miles J.

doi:10.1364/oe.17.022718

Cited by 65 publications

(65 citation statements)

References 24 publications

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“…Our system is similar to that described in [22], designed around a commercially available inverted microscope (Axiovert 200, Zeiss). A 4 W 800 nm wavelength laser beam, generated by a titanium sapphire ring laser (899, Coherent) pumped by a solid state laser (Verdi-V18, Coherent) is expanded to fill an electrically addressed spatial light modulator (P512-0785, Boulder Nonlinear Systems) controlled using a LabVIEW (National Instruments) interface, with each hologram calculation performed on a PC graphics card (nVidia, Quadro FX 5600) in under 1 ms [23]. The beam is then passed through a polarising beam splitter and imaged onto the back aperture of an objective lens (1.3 NA 100 × Plan-Neufluar, Zeiss).…”

Section: Probe Control and Measurementmentioning

confidence: 99%

“…In our system the maximum refresh rate of the spatial light modulator is 203 Hz, and the maximum camera frame rate over the required region of interest is 1 kHz with an integration time of 1 ms. The reaction time from measurement of probe position to trap movement is ∼10 ms -more details of this are discussed in [23]. These time delays limit the maximum stiffness attainable with closed-loop control.…”

Section: Position and Rotation Clampingmentioning

confidence: 99%

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An optically actuated surface scanning probe

et al. 2012

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Abstract:We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultra-low, femto-Newton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of ∼ 11 nm. Using equipartition theory, we estimate that an average force of only ∼ 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples. 288-290 (1986). 2. A. Pralle, M. Prummer, E. L. Florin, E. H. K. Stelzer, and J. K. H. Horber, "Three-dimensional high-resolution particle tracking for optical tweezers by forward scattered light," Microsc.

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Section: Probe Control and Measurementmentioning

confidence: 99%

Section: Position and Rotation Clampingmentioning

confidence: 99%

An optically actuated surface scanning probe

et al. 2012

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“…The OpenGL Shader Language kernel that renders the holograms is able to be modified from within LABVIEW, making it easy to change the holograms that are rendered. It is also possible to add tabs and plugins to the graphical interface to change the control logic (for example, to effect closed loop control 20,30 ). Image analysis allows us to track the particles in our traps using either centre of mass or a symmetry-based algorithm, implemented as a dynamic-link library (DLL) written in C and called from LABVIEW.…”

Section: Software Controlmentioning

confidence: 99%

“…We have incorporated our own SLM control software, developed using a combination of LABVIEW and OpenGL, which is capable of generating holograms at hundreds of Hz. 20 In ada) Electronic mail: Graham.Gibson@glasgow.ac.uk. URL: www.gla.ac.uk/ schools/physics/research/groups/optics/.…”

Section: Introductionmentioning

confidence: 99%

A compact holographic optical tweezers instrument

Gibson

Bowman

Linnenberger

et al. 2012

Review of Scientific Instruments

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Visual and dynamical measurement of Rayleigh-Benard convection by using fiber-based digital holographic interferometry J. Appl. Phys. 112, 113113 (2012) Guide-star-based computational adaptive optics for broadband interferometric tomography Appl. Phys. Lett. 101, 221117 (2012) Limits of elemental contrast by low energy electron point source holography J. Appl. Phys. 110, 094305 (2011) Cantilever biosensor reader using a common-path, holographic optical interferometer Appl. Phys. Lett. 97, 221110 (2010) Extended depth of focus in a particle field measurement using a single-shot digital hologram Appl. Phys. Lett. 95, 201103 (2009) Additional information on Rev. Sci. Instrum. Holographic optical tweezers have found many applications including the construction of complex micron-scale 3D structures and the control of tools and probes for position, force, and viscosity measurement. We have developed a compact, stable, holographic optical tweezers instrument which can be easily transported and is compatible with a wide range of microscopy techniques, making it a valuable tool for collaborative research. The instrument measures approximately 30×30×35 cm and is designed around a custom inverted microscope, incorporating a fibre laser operating at 1070 nm. We designed the control software to be easily accessible for the non-specialist, and have further improved its ease of use with a multi-touch iPad interface. A high-speed camera allows multiple trapped objects to be tracked simultaneously. We demonstrate that the compact instrument is stable to 0.5 nm for a 10 s measurement time by plotting the Allan variance of the measured position of a trapped 2 μm silica bead. We also present a range of objects that have been successfully manipulated.

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“…For stereoscopic imaging, the only image analysis required is tracking objects in 2D, which can be achieved to sub-pixel accuracy at up to several kHz [10], enabling the measurement of power spectra and the use of this technique in closed-loop systems [23,24]. We fit to the marginal distributions of an image to determine the x and y positions of the bead with subpixel accuracy.…”

Section: Optical Systemmentioning

confidence: 99%

Particle tracking stereomicroscopy in optical tweezers: Control of trap shape

Bowman¹,

Gibson²,

Padgett³

2010

Opt. Express

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Abstract:We present an optical system capable of generating stereoscopic images to track trapped particles in three dimensions. Two-dimensional particle tracking on each image yields three dimensional position information. Our approach allows the use of a high numerical aperture (NA= 1.3) objective and large separation angle, such that particles can be tracked axially with resolution of 3 nm at 340 Hz. Spatial Light Modulators (SLMs), the diffractive elements used to steer and split laser beams in Holographic Optical Tweezers, are also capable of more general operations. We use one here to vary the ratio of lateral to axial trap stiffness by changing the shape of the beam at the back aperture of the microscope objective. Beams which concentrate their optical power at the extremes of the back aperture give rise to much more efficient axial trapping. The flexibility of using an SLM allows us to create multiple traps with different shapes.

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Increasing trap stiffness with position clamping in holographic optical tweezers

Cited by 65 publications

References 24 publications

An optically actuated surface scanning probe

An optically actuated surface scanning probe

A compact holographic optical tweezers instrument

Particle tracking stereomicroscopy in optical tweezers: Control of trap shape

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