Double optical tweezers for ultrasensitive force spectroscopy in microsphere Mie scattering

Fontes, Adriana; Neves, Antonio Alvaro Ranha; Moreira, Wendel L.; Thomaz, André A. de; Barbosa, L. C.; César, Carlos L.; Paula, Ana

doi:10.1063/1.2137896

Cited by 26 publications

(20 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For MDR, Fig. 3 it can be observed that each beam polarization excited each mode, TM or TE, separately as has been demonstrated previously [6]. This can be intuitively understood by noticing that only the radial component of the electric field will excite the TM mode, and only the radial component of the magnetic field will excite the TE modes.…”

Section: Resultsmentioning

confidence: 64%

“…We have shown that a double optical tweezers can be used to perform an ultrasensitive force spectroscopy by observing forces due to the light scattering and selectively coupling the light to either the TE, the TM or both TE and TM microsphere modes in a single isolated particle as function of the beam polarization and position [6,7]. Our results showed how careful one has to be when using optical force models for mechanical properties measurements.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Electromagnetic forces for an arbitrary optical trapping of a spherical dielectric

Neves¹,

Fontes²,

Pozzo³

et al. 2006

Opt. Express

View full text Add to dashboard Cite

Analytical solution for optical trapping force on a spherical dielectric particle for an arbitrary positioned focused beam is presented in a generalized Lorenz-Mie and vectorial diffraction theory. In this case the exact electromagnetic field is considered in the focal region. A double tweezers setup was employed to perform ultra sensitive force spectroscopy and observe the forces, demonstrating the selectively couple of the transverse electric (TE), transverse magnetic (TM) modes by means of the beam polarization and positioning, and to observe correspondent morphology-dependent resonances (MDR) as a change in the optical force. The theoretical prediction of the theory agrees well with the experimental results. The algorithm presented here can be easily extended to other beam geometries and scattering particles. G. Gouesbet, B. Maheu, G. Grehan, "Light scattering from a sphere arbitrarily located in a Gaussian beam using Bromwich formulation," J Opt Soc Am A, 5, 1427-1443 (1988

show abstract

Section: Resultsmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 98%

Electromagnetic forces for an arbitrary optical trapping of a spherical dielectric

Neves¹,

Fontes²,

Pozzo³

et al. 2006

Opt. Express

View full text Add to dashboard Cite

show abstract

“…Polarization effects might be relevant, on the other hand, when the sphere is at a distance from the axis larger than or of the order of the radius [35]. They will be discussed in a forthcoming work.…”

Section: Discussionmentioning

confidence: 99%

Towards absolute calibration of optical tweezers

et al. 2007

View full text Add to dashboard Cite

Aiming at absolute force calibration of optical tweezers, following a critical review of proposed theoretical models, we present and test the results of MDSA (Mie-Debye-Spherical Aberration) theory, an extension of a previous (MD) model, taking account of spherical aberration at the glass/water interface. This first-principles theory is formulated entirely in terms of experimentally accessible parameters (none adjustable). Careful experimental tests of the MDSA theory, undertaken at two laboratories, with very different setups, are described. A detailed description is given of the procedures employed to measure laser beam waist, local beam power at the transparent microspheres trapped by the tweezers, microsphere radius and the trap transverse stiffness, as a function of radius and height in the (inverted microscope) sample chamber. We find generally very good agreement with MDSA theory predictions, for a wide size range, from the Rayleigh domain to large radii, including the values most often employed in practice, and at different chamber heights, both with objective overfilling and underfilling. The results asymptotically approach geometrical optics in the mean over size intervals, as they should, and this already happens for size parameters not much larger than unity. MDSA predictions for the trapping threshold, position of stiffness peak, stiffness variation with height, multiple equilibrium points and 'hopping' effects among them are verified. Remaining discrepancies are ascribed to focus degradation, possibly arising from objective aberrations in the infrared, not yet included in MDSA theory.

show abstract

“…Some evidence for the resonance force enhancement has been obtained in waveguide couplers 35 and in the case of off-axially shifted focused beams. 36 More recently, the notable advance in this field has been made based on theoretical demonstration of high peak-to-background resonant force ratios in evanescent prism couplers. 37,38 However, many properties of resonant light forces still await a thorough investigation.…”

Section: Introductionmentioning

confidence: 99%

Giant resonant light forces in microspherical photonics

Svitelskiy

Maslov³

et al. 2013

Light Sci Appl

View full text Add to dashboard Cite

Resonant light pressure effects can open new degrees of freedom in optical manipulation with microparticles, but they have been traditionally considered as relatively subtle effects. Using a simplified two-dimensional model of surface electromagnetic waves evanescently coupled to whispering gallery modes (WGMs) in transparent circular cavities, we show that under resonant conditions the peaks of the optical forces can approach theoretical limits imposed by the momentum conservation law on totally absorbing particles. Experimentally, we proved the existence of strong peaks of the optical forces by studying the optical propulsion of dielectric microspheres along tapered microfibers. We observed giant optical propelling velocities ,0.45 mm s 21 for some of the 15-20 mm polystyrene microspheres in water for guided powers limited at ,43 mW. Such velocities exceed previous observations by more than an order of magnitude, thereby providing evidence for the strongly enhanced resonant optical forces. We analyzed the statistical properties of the velocity distribution function measured for slightly disordered (,1% size variations) ensembles of microspheres with mean diameters varying from 3 to 20 mm. These results demonstrate a principal possibility of optical sorting of microspheres with the positions of WGM resonances overlapped at the wavelength of the laser source. They can be used as building blocks of the lossless coupled resonator optical waveguides and various integrated optoelectronics devices.

show abstract

Double optical tweezers for ultrasensitive force spectroscopy in microsphere Mie scattering

Cited by 26 publications

References 20 publications

Electromagnetic forces for an arbitrary optical trapping of a spherical dielectric

Electromagnetic forces for an arbitrary optical trapping of a spherical dielectric

Towards absolute calibration of optical tweezers

Giant resonant light forces in microspherical photonics

Contact Info

Product

Resources

About