Laser trapping of deformable objects

Murazawa, Naoki; Juodkazis, Saulius; Misawa, Hiroaki; Wakatsuki, Hiroshi

doi:10.1364/oe.15.013310

Cited by 9 publications

(8 citation statements)

References 21 publications

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“…There are also push-pull forces exerted on the interfaces due to the very same Fresnel scaling laws, since Force = Power / c , where c is velocity of light inside the medium. As light passes through the boundary, a mechanical force is applied3334. This might affect molecular alignment and stretching of analyte species and be utilized for further control over the SERS signal.…”

Section: Discussionmentioning

confidence: 99%

Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

Jayawardhana

Rosa

Juodkazis

et al. 2013

Sci Rep

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Surface-enhanced Raman scattering (SERS) is attracting increasing interest for chemical sensing, surface science research and as an intriguing challenge in nanoscale plasmonic engineering. Several studies have shown that SERS intensities are increased when metal island film substrates are excited through a transparent base material, rather than directly through air. However, to our knowledge, the origin of this additional enhancement has never been satisfactorily explained. In this paper, finite difference time domain modeling is presented to show that the electric field intensity at the dielectric interface between metal particles is higher for “far-side” excitation than “near-side”. This is reasonably consistent with the observed enhancement for silver islands on SiO2. The modeling results are supported by a simple analytical model based on Fresnel reflection at the interface, which suggests that the additional SERS signal is caused by near-field enhancement of the electric field due to the phase shift at the dielectric interface.

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Section: Discussionmentioning

confidence: 99%

Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

Jayawardhana

Rosa

Juodkazis

et al. 2013

Sci Rep

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“…Shape changes induced by linear momentum of light induces dimples on the surface of bubbles and facilitates trapping of an object similar to the SIBA principle. [ 119 ] This principle of laser pinning of a bubble was implemented to remove them from a glass melt. Bubbles become unstable and undergo shape change and pinning followed by disintegration.…”

Section: Optical Trapping In Plasmonic Nanocavitiesmentioning

confidence: 99%

Novel Plasmonic Nanocavities for Optical Trapping‐Assisted Biosensing Applications

Koya

Cunha

Guo

et al. 2020

Advanced Optical Materials

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However, due to the intrinsic low optical response of small objects, there has been a clear trade-off between the size of a material and its response to light. [5] Recently, plasmonic nanostructures have emerged as leading platforms to enhance the weak optical signals of low dimensional materials including quantum dots (QDs), [6] small molecules, [7,8] and 2D monolayers. [9] The plasmonic enhancement of linear and nonlinear optical processes capitalizes on the near-and far-field properties of metallic (e.g., gold and silver) nanostructures. [10] One of the defining features of plasmonic nanostructures is their potential to confine light into deep subwavelength volumes, which has opened a new door to trap and manipulate dielectric, metallic, and biological nano-objects. [11] Moreover, metallic nanostructures are characterized by their capability to amplify the intensity of optical fields by orders of magnitude. The enhancement of local field intensity is attributed to the resonance of plasmon polaritons arising from the coupling of external electromagnetic fields to the collective oscillations of the conduction electrons. [12] A small perturbation (or change in the refractive index) of the near field zone of plasmonic nanostructures leads to significant shift in the plasmon polariton resonance wavelength, which has important implications for surface-enhanced sensing and spectroscopic applications. [13,14] Thus, for the ad-hoc enhancement of optical Plasmonic nanocavities have proved to confine electromagnetic fields into deep subwavelength volumes, implying their potentials for enhanced optical trapping and sensing of nanoparticles. In this review, the fundamentals and performances of various plasmonic nanocavity geometries are explored with specific emphasis on trapping and detection of small molecules and single nanoparticles. These applications capitalize on the local field intensity, which in turn depends on the size of plasmonic nanocavities. Indeed, properly designed structures provide significant local field intensity and deep trapping potential, leading to manipulation of nano-objects with low laser power. The relationship between optical trappinginduced resonance shift and potential energy of plasmonic nanocavity can be analytically expressed in terms of the intercavity field intensity. Within this framework, recent experimental works on trapping and sensing of single nanoparticles and small molecules with plasmonic nanotweezers are discussed. Furthermore, significant consideration is given to conjugation of optical tweezers with Raman spectroscopy, with the aim of developing innovative biosensors. These devices, which take the advantages of plasmonic nanocavities, will be capable of trapping and detecting nanoparticles at the single molecule level.

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“…As light passes throughout the boundary, mechanical force is applied. 17,18 This might affect molecular alignment and stretching of analyte species and be utilized for further control over the SERS signal.…”

Section: Resultsmentioning

confidence: 99%

Additional enhancement in surface-enhanced Raman scattering due to excitation geometry

Rosa¹,

Jayawardhana²,

Juodkazis³

et al. 2012

SPIE Proceedings

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It is well known that surface-enhanced Raman scattering (SERS) substrates based on metal island films exhibit higher levels of enhancement when excited through a transparent base material than when excited directly through air. However, to our knowledge, the origin of this enhancement has never been satisfactorily explained. An initial suggestion that the additional enhancement was due to a "nearest layer effect" cannot account for the observation of additional enhancement for monolayer adsorbates. In this paper, finite difference time domain (FDTD) modelling is presented to show that the electric field intensity in between metal particles at the interface is higher for "far-side" excitation. This is reasonably consistent with the observed enhancement for silver islands on SiO2. The modelling results are in agreement with a simple physical model based on Fresnel reflection at the interface. This suggests that the additional enhancement is due to a near-field enhancement of the electric field due to the phase shift at the dielectric interface, when the light passes from the higher to the lower region of refractive index

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Laser trapping of deformable objects

Cited by 9 publications

References 21 publications

Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism

Novel Plasmonic Nanocavities for Optical Trapping‐Assisted Biosensing Applications

Additional enhancement in surface-enhanced Raman scattering due to excitation geometry

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