Multi-frequency near-field scanning optical microscopy

Kohlgraf-Owens, Dana C.; Greusard, L.; Sukhov, Sergey; Wilde, Yannick De; Dogariu, Aristide

doi:10.1088/0957-4484/25/3/035203

Cited by 7 publications

(11 citation statements)

References 18 publications

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“…Previously, a novel AFM based Photo Induced Force Microscopy (PIFM) scheme was introduced to detect and image molecular resonances at nanometer level5678 and produce nanoscale optical force maps910. Near-field Scanning Optical Microscopy (NSOM) has been used to study light-matter interaction beyond the diffraction limit with important applications in many areas of nano-optics, materials science, chemistry and biology11.…”

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confidence: 99%

Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces

Huang

Tamma

Mardy

et al. 2015

Sci Rep

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We demonstrate the application of Atomic Force Microscopy (AFM) for mapping optical near-fields with nanometer resolution, limited only by the AFM probe geometry. By detecting the optical force between a gold coated AFM probe and its image dipole on a glass substrate, we profile the electric field distributions of tightly focused laser beams with different polarizations. The experimentally recorded focal force maps agree well with theoretical predictions based on a dipole-dipole interaction model. We experimentally estimate the aspect ratio of the apex of gold coated AFM probe using only optical forces. We also show that the optical force between a sharp gold coated AFM probe and a spherical gold nanoparticle of radius 15 nm, is indicative of the electric field distribution between the two interacting particles. Photo Induced Force Microscopy (PIFM) allows for background free, thermal noise limited mechanical imaging of optical phenomenon over wide range of wavelengths from Visible to RF with detection sensitivity limited only by AFM performance.

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confidence: 99%

Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces

Huang

Tamma

Mardy

et al. 2015

Sci Rep

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“…As expected, the optical force signal is higher over the coverslip than over the metal particles with peaks located the particle corners. From [10].…”

Section: Discussionmentioning

confidence: 99%

“…An example image is shown in Figure 6 where an array of gold triangles fabricated on a cover slip via nanosphere lithography was measured using a chromium coated AFM probe. A direct comparison of the topography in Figure 6A with the optical force image shown in Figure 6B clearly demonstrates that the force is higher over the open regions of the cover slip than over the particles and also that the largest values of the optical force are localized at the particle vertices [10].…”

Section: Oif In Modulated Fieldsmentioning

confidence: 93%

“…When the strength of these optical forces is comparable to the surface forces, they can induce a measureable effect upon the feedback mechanism. Readout of the changes in cantilever properties may be performed using optical detection [10], piezoelectric [10,11] or piezoresistive effects [12].…”

Section: Radiation Forces In Spmmentioning

confidence: 99%

“…By modulating the light at a sufficiently high frequency (∼50 kHz or more) and using separate lock-in detection at this frequency, one can generate a separate channel with the OIF information, which significantly reduces the influence of thermal effects. The best choice for this modulation frequency is either near a resonance frequency of the tuning fork or cantilever [10] or selected such that a sum or difference of multiple excitation frequencies is near a resonance frequency [83]. In this case, the signal strength of the generated signal will be amplified by a factor of ∼Q on resonance.…”

Section: Oif In Modulated Fieldsmentioning

confidence: 99%

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Optically induced forces in scanning probe microscopy

et al. 2014

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Typical measurements of light in the near-field utilize a photodetector such as a photomultiplier tube or a photodiode, which is placed remotely from the region under test. This kind of detection has many draw-backs including the necessity to detect light in the far-field, the influence of background propagating radiation, the relatively narrowband operation of photodetectors which complicates the operation over a wide wavelength range, and the difficulty in detecting radiation in the far-IR and THz. Here we review an alternative near-field light measurement technique based on the detection of optically induced forces acting on the scanning probe. This type of detection overcomes some of the above limitations, permitting true broad-band detection of light directly in the near-field with a single detector. The physical origins and the main characteristics of optical force detection are reviewed. In addition, intrinsic effects of the inherent optical forces for certain operation modalities of scanning probe microscopy are discussed. Finally, we review practical applications of optical force detection of interest for the broader field of the scanning probe microscopy.

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Resonant optical gradient force interaction for nano-imaging and -spectroscopy

Yang

Raschke

2016

New J. Phys.

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The optical gradient force provides optomechanical interactions, for particle trapping and manipulation, as well as for near-field optical imaging in scanning probe microscopy. Based on recent spectroscopic experiments, its extension and use for a novel form of chemical scanning probe nanoimaging was proposed. Here, we provide the theoretical basis in terms of spectral behavior, resonant enhancement, and distance dependence of the optical gradient force from numerical simulations in a coupled nanoparticle model geometry. We predict an asymmetric line shape of the optical gradient force for molecular electronic or vibrational resonances, corresponding to the real part of the dielectric function of the sample materials. Yet the line shape can become symmetric and absorptive for collective polaritonic excitations. The corresponding magnitudes of the force range from fN to pN, respectively. The distance dependence scales considerably less steeply than simple point dipole model predictions due to multipole effects. The combination of these characteristics of the optical gradient force offers the chance to experimentally distinguish it from competing processes such as thermal expansion induced forces. In addition we provide a perspective for further resonant enhancement and control of optical forces.

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Multi-frequency near-field scanning optical microscopy

Cited by 7 publications

References 18 publications

Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces

Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces

Optically induced forces in scanning probe microscopy

Resonant optical gradient force interaction for nano-imaging and -spectroscopy

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