Near-field spatial mapping of strongly interacting multiple plasmonic infrared antennas

Grefe, Sarah E.; Leiva, Daan; Mastel, Stefan; Dhuey, Scott; Cabrini, Stefano; Schuck, P. James; Abate, Yohannes

doi:10.1039/c3cp53104j

Cited by 25 publications

(24 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A promising approach to access the full polarization state of the near field around an antenna is scattering-type scanning near-field optical microscopy (s-SNOM) [18][19][20][21][22][23][24][25][26][27][28][29]. In s-SNOM, a scanning tip acts as a scatterer that transfers the near field induced in the vicinity of a nanoantenna to the far field, where it can be collected by a detector.…”

Section: Introductionmentioning

confidence: 99%

Mapping the near fields of plasmonic nanoantennas by scattering‐type scanning near‐field optical microscopy

Neuman

Alonso‐González

García‐Etxarri

et al. 2015

Laser & Photonics Reviews

View full text Add to dashboard Cite

Near-field optical microscopy techniques provide information on the amplitude and phase of local fields in samples of interest in nanooptics. However, the information on the near field is typically obtained by converting it into propagating far fields where the signal is detected. This is the case, for instance, in polarization-resolved scattering-type scanning near-field optical microscopy (s-SNOM), where a sharp dielectric tip scatters the local near field off the antenna to the far field. Up to now, basic models have interpreted S-and P-polarized maps obtained in s-SNOM as directly proportional to the in-plane (E x or E y ) and out-of-plane (E z ) near-field components of the antenna, respectively, at the position of the probing tip. Here, a novel model that includes the multiple-scattering process of the probing tip and the nanoantenna is developed, with use of the reciprocity theorem of electromagnetism. This novel theoretical framework provides new insights into the interpretation of s-SNOM near-field maps: the model reveals that the fields detected by polarization-resolved interferometric s-SNOM do not correlate with a single component of the local near field, but rather with a complex combination of the different local nearfield components at each point (E x , E y and E z ). Furthermore, depending on the detection scheme (S-or P-polarization), a different scaling of the scattered fields as a function of the local near-field enhancement is obtained. The theoretical findings are corroborated by s-SNOM experiments which map the near field of linear and gap plasmonic antennas. This new interpretation of nanoantenna s-SNOM maps as a complex-valued combination of vectorial local near fields is crucial to correctly understand scattering-type near-field microscopy measurements as well as to interpret the signals obtained in field-enhanced spectroscopy.

show abstract

Section: Introductionmentioning

confidence: 99%

Mapping the near fields of plasmonic nanoantennas by scattering‐type scanning near‐field optical microscopy

Neuman

Alonso‐González

García‐Etxarri

et al. 2015

Laser & Photonics Reviews

View full text Add to dashboard Cite

show abstract

“…The choice of the bowtie nanoantenna design for the present demonstration is based on three considerations: (i) in a wire-dipole antenna with width w ( h, the field penetration on the lateral walls would be longer than the antenna size, but for w ¼ h ¼ 250 nm, the antenna gap would be rather wide; (ii) if compared to linear dipoles, a triangular patch presents a hotspot at the narrower end, which is stronger and smaller than that at the broader end; 31 (iii) the bowtie antenna can be considered as two coupled triangular patches, with strong field confinement and field enhancement high enough to be measured. The final design is reported in Fig.…”

Section: à2mentioning

confidence: 99%

Mapping the electromagnetic field confinement in the gap of germanium nanoantennas with plasma wavelength of 4.5 micrometers

Calandrini

Venanzi

Appugliese

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

We study plasmonic nanoantennas for molecular sensing in the mid-infrared made of heavily doped germanium, epitaxially grown with a bottom-up doping process and featuring free carrier density in excess of 1020 cm−3. The dielectric function of the 250 nm thick germanium film is determined, and bow-tie antennas are designed, fabricated, and embedded in a polymer. By using a near-field photoexpansion mapping technique at λ = 5.8 μm, we demonstrate the existence in the antenna gap of an electromagnetic energy density hotspot of diameter below 100 nm and confinement volume 105 times smaller than λ3

show abstract

“…The dipolar and the magnetic resonance intensity drops by 40% and 23% respectively as we migrate from the original structure to the modified one. In the modified structure, the dipolar-dipolar and charge-charge interaction are missing and dipolar-charge interaction is weakened 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 13 alongside the weakening of near field array effect [40]. Due to these combined effects, we see the noticeable degradation of dipolar resonance intensity.…”

Section: Study Of Parametersmentioning

confidence: 96%

Dipolar Resonance Enhancement and Magnetic Resonance in Cross-Coupled Bow-Tie Nanoantenna Array by Plasmonic Cavity

Hasan

Pitchappa

et al. 2015

ACS Photonics

View full text Add to dashboard Cite

We experimentally demonstrate a simple approach for surface current engineering in a cross-coupled bow-tie nanoantenna by inserting a plasmonic cavity that simultaneously offers (i) improved Fano-like dipolar resonance contrast, (ii) electrically induced magnetic resonance, and (iii) enhanced sensitivity. By introducing a small geometric perturbation, we propose two physical parameters, offset (f) and split gap (s), for strong modulation of resonance location and intensity. We report at least 3.75-fold better dipolar resonance compared with the conventional design and demonstrate a unique mechanism for exciting magnetic plasmonic resonance. Finally, we obtain a large wavelength shift of 777.5 and 904 nm per refractive index unit (RIU) with a thin PMMA coating (110 nm) for the dipolar resonance and magnetic resonance, respectively. Numerical study indicates the potential of the proposed bow-tie nanoantenna array structure with a selfsimilar plasmonic cavity (SSP BNA) for sensitive recording of binding events of molecules such as DNA by reestablishing conduction current and providing "on" and "off" states. The high-density plasmonic antenna array structure will be promising for engineering applications in optical magnetism, magnetoplasmonics, optical trapping, and massively parallel ultrasensitive differential detection of molecular fingerprints.

show abstract

Near-field spatial mapping of strongly interacting multiple plasmonic infrared antennas

Cited by 25 publications

References 56 publications

Mapping the near fields of plasmonic nanoantennas by scattering‐type scanning near‐field optical microscopy

Mapping the near fields of plasmonic nanoantennas by scattering‐type scanning near‐field optical microscopy

Mapping the electromagnetic field confinement in the gap of germanium nanoantennas with plasma wavelength of 4.5 micrometers

Dipolar Resonance Enhancement and Magnetic Resonance in Cross-Coupled Bow-Tie Nanoantenna Array by Plasmonic Cavity

Contact Info

Product

Resources

About