Coupled T-Shaped Optical Antennas with Two Resonances Localized in a Common Nanogap

Abstract

Resonant optical antennas with nanoscale gaps are of high interest due to their ability to enhance electric fields in localized subdiffraction-limited volumes. They are especially attractive for coupling with quantum emitters. One challenge for applications that exhibit a spectral shift is to fabricate nanoantennas that provide two distinct resonances at the excitation and emission frequency, respectively. We propose a coupled T-shaped nanoantenna structure that provides independently controllable resonances with a common electromagnetic hot spot in the antenna gap. We demonstrate the fabrication of such structures and investigate experimentally and theoretically their spatial, time-integrated spectral- and polarization-dependent electromagnetic field properties. The nanoantennas exhibit two resonances with unique spectral and polarization responses. The resonance wavelengths are independently tailored by varying the geometry of individual T-shaped antennas.

Polarized Nonlinear Nanoscopy of Metal Nanostructures

“…Observation of spatial phase profiles is however delicate and has so far relied on indirect directionality measurements 52,53 or near field measurements 21 . This method is able to reveal such effect, and could be advantageously coupled to dark field spectroscopy and transmission electron microscopy to investigate the existence and vectorial nature of bonding and anti-bonding modes in multimeric nanorod structures 2,[54][55][56] or more complex oligomeric structures.…”

“…One of the key factors that control their nanoscale optical properties is the polarization of incident electromagnetic fields, which influences the amplitude and polarization of scattered fields. By varying the excitation polarization, one can not only tune the spectral properties of metal nanostructures of complex shapes 1,2 , but also the spatial and vectorial properties of their local fields at the nanoscale. Controlling these properties has opened new routes for optimized biosensors, contrast agents and nano-antennas [3][4][5] , dedicated to new device functions [6][7][8][9][10][11] , but also for the exploration of fundamental light matter coupling properties [12][13][14] .…”

Multi-resonant silicon nanoantennas by evolutionary multi-objective optimization

“…Examples go far beyond multiresonant antennas 41 or polarization dependent tailored optical behavior. 42,43 For instance nanoantennas for optimized nonlinear optical effects are particularly promising with respect to inverse design methods. For the maximization of optical second harmonic generation for instance, 44,45 strong resonances could be concurrently designed at the fundamental and harmonic frequencies and furthermore tailored to yield strongest field-enhancements just at the surface of the nanoparticle.…”

Polarization-Converting Plasmonic Nanoantennas for Light Absorption Enhancement in Anisotropic 2D Black Phosphorus

“…They also confine light in the antenna gap which leads to strong near-field intensity and thus light absorption enhancements. T-shaped nanoantennas were previously proposed as a bimodal antenna structure with two independent resonances localized in a single nanogap [4].…”