Apertureless scanning near-field optical microscopy: a comparison between homodyne and heterodyne approaches

Gomez, Lewis Mortimer; Bachelot, Renaud; Bouhélier, Alexandre; Wiederrecht, Gary P.; Chang, Shun‐Ping; Gray, Stephen K.; Feng, Huan; Jeon, Seokwoo; Rogers, John A.; Castro, Miguel E.; Blaize, Sylvain; Stefanon, Ilan; Lerondel, Gilles; Royer, Pascal

doi:10.1364/josab.23.000823

Cited by 92 publications

(74 citation statements)

References 29 publications

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“…Characteristic features help us narrow down the options and avoid consideration of all reflected/scattered waves reaching the photodiode (for theoretical aspects of a full-wave approach, especially also for the application of the reciprocity theory, see Refs. [18][19][20][21]; for a consideration of the role of light that is scattered at the edges but does not convert to SPPs, see comments in Supplemental D). The modulations must arise from SPPs generated at or reflected from the edges to form intensity peaks/valleys parallel to them.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

et al. 2017

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Abstract:We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM). The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.

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Section: Experimental Results and Analysismentioning

confidence: 99%

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

et al. 2017

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“…Harmonic generation occurs due to the nonlinear dependence of the near-field signal on the tip-sample distance described by the signal Fourier series expansion. 103,[136][137][138] The signal-tobackground ratio is increased by demodulation to higher order harmonics. Utilizing this technique allows for interferometric collection of pure optical contrast images.…”

Section: Applicationmentioning

confidence: 99%

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

2016

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Near-field optics and superlenses for imaging beyond Abbe's diffraction limit are reviewed. A comprehensive and contemporary background is given on scanning near-field microscopy and superlensing. Attention is brought to recent research leveraging scanning near-field optical microscopy with superlenses for new nano-imaging capabilities. Future research directions are explored for realizing the goal of low-cost and high-performance sub-diffraction-limited imaging systems. © 2016 Author(s)

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“…[20][21][22][23] However, the notorious interference and electromagnetic coupling of the probe tip especially to metallic samples continues to be a troublesome limiting factor. Often it prevents even qualitative interpretation of aSNOM images.…”

Section: Introductionmentioning

confidence: 99%

“…The photoelectric signal is therefore not proportional to scattered intensity but the electric field itself. [20][21][22][23] Recording it twice with a relative phase shift of 90°in the reference yields optical amplitude and phase information. Figure 2 (and Figure 4) show representative measurement results for small and large nanodisks.…”

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confidence: 99%

Direct Near-Field Optical Imaging of Higher Order Plasmonic Resonances

et al. 2008

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We map in real space and by purely optical means near-field optical information of localized surface plasmon polariton (LSPP) resonances excited in nanoscopic particles. We demonstrate that careful polarization control enables apertureless scanning near-field optical microscopy (aSNOM) to image dipolar and quadrupolar LSPPs of the bare sample with high fidelity in both amplitude and phase. This establishes a routine method for in situ optical microscopy of plasmonic and other resonant structures under ambient conditions.When nanoscopic metallic structures are illuminated at adequate frequencies, the incoming radiation can couple to charge density oscillations and excite so-called localized surface plasmon polaritons (LSPPs). Recently, the nearfield enhancing qualities of LSPPs have been realized to hold promise for a bounty of novel applications in optics and photonics. 1 These applications often rely on the fine details of LSPPs and their interactions with nanostructures. For example, in the fields of ultra sensitive bio(chemo)detectors 2,3 or plasmonic metamaterials, 4-6 direct near-field optical microscopy of LSPPs would be of great benefit. While spectroscopic far-field properties of LSPP resonances are routinely accessible, real-space near-field information is difficult to obtain.To assess LSPPs of real nanostructures, microscopy techniques are required that are capable of spatially resolving the relevant structure sizes. One approach is the subsequent investigation by means of atomic force microscopy (AFM) of chemical or mechanical changes induced in suitable substrates by the excitation of optical eigenmodes. 7,8 A second approach uses electron energy loss or induced cathode-luminescence scanning electron microscopy to map LSPPs with nanometer resolution. 9,10 This technique requires vacuum compatible samples.For many applications in plasmonics, an all-optical detection of LSPPs with ultimate spatial resolution is called for. Characterizing local optical fields under ambient conditions has been achieved with AFM by carrying nanoscopic optical probes to the immediate vicinity of the nanostructures. [11][12][13][14][15][16] However, such an optical probe has to perform contradicting tasks: as an "optical nano-antenna", its reception/emission efficiency improves with larger size, 17 and as a near-field detector, the achievable spatial resolution improves with smaller size, which can also reduce parasitic interference and coupling effects between probe and sample. 14 In this communication, we demonstrate that these competing demands can be concerted by polarization control of the exciting and scattered radiation, even with off-the-shelf AFM tips as optical probes. We are able to clearly map dipolar and quadrupolar LSPPs, both in phase and in amplitude.In apertureless scanning near field optical microscopy (aSNOM), parasitic background signal from bulk scattering in the sample and tip is often suppressed by anharmonic lockin detection techniques, 18,19 and homodyne, heterodyne, or pseudoheterodyne inte...

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Apertureless scanning near-field optical microscopy: a comparison between homodyne and heterodyne approaches

Cited by 92 publications

References 29 publications

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

Review of near-field optics and superlenses for sub-diffraction-limited nano-imaging

Direct Near-Field Optical Imaging of Higher Order Plasmonic Resonances

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