Thorsten Feichtner
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View article: Double Helical Plasmonic Antennas
Double Helical Plasmonic Antennas Open
Plasmonic double helical antennas are a means to funnel circularly polarized light down to the nanoscale. Here, an existing design tool for single helices is extended to the case of double helices and used to design antennas that combine l…
View article: Modulation of surface response in a single plasmonic nanoresonator
Modulation of surface response in a single plasmonic nanoresonator Open
Scattering of light by plasmonic nanoparticles is classically described using bulk material properties with infinitesimally thin boundaries. However, because of the quantum nature of electrons, real interfaces have finite thickness, leadin…
View article: Double helical plasmonic antennas
Double helical plasmonic antennas Open
Plasmonic double helical antennas are a means to funnel circularly polarized light down to the nanoscale. Here, an existing design tool for single helices is extended to the case of double helices and used to design antennas that combine l…
View article: Chiral and directional optical emission from a dipole source coupled to a helical plasmonic antenna
Chiral and directional optical emission from a dipole source coupled to a helical plasmonic antenna Open
Plasmonic antennas with helical geometry can convert linearly polarized dipole radiation into purely circularly polarized far-fields, and vice versa. Besides large Purcell enhancements, they possess a wide tunability due to the geometry de…
View article: Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a Novel SERS Sensing Platform
Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a Novel SERS Sensing Platform Open
Achieving reliable and quantifiable performance in large‐area surface‐enhanced Raman spectroscopy (SERS) substrates poses a formidable challenge, demanding signal enhancement while ensuring response uniformity and reproducibility. Conventi…
View article: Controlling Field Asymmetry in Nanoscale Gaps for Second Harmonic Generation
Controlling Field Asymmetry in Nanoscale Gaps for Second Harmonic Generation Open
Field hotspots in nanoscale gaps of plasmonic antennas can boost nonlinear processes such as harmonic generation, photoelectron emission, and ultrafast electron transport. Alongside large field enhancement, such phenomena often require con…
View article: Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a SERS Sensing Platform
Evolutionary Optimized, Monocrystalline Gold Double Wire Gratings as a SERS Sensing Platform Open
Achieving reliable and quantifiable performance in large-area surface-enhanced Raman spectroscopy (SERS) substrates has long been a formidable challenge. It requires substantial signal enhancement while maintaining a reproducible and unifo…
View article: Direct electrical modulation of surface response in a single plasmonic nanoresonator
Direct electrical modulation of surface response in a single plasmonic nanoresonator Open
Classical electrodynamics describes the optical response of systems using bulk electronic properties and infinitesimally thin boundaries. However, due to the quantum nature of electrons, interfaces have a finite thickness. Non-classical su…
View article: Controlling field asymmetry in nanoscale gaps for second harmonic generation
Controlling field asymmetry in nanoscale gaps for second harmonic generation Open
Plasmonic dimer antennas create strong field enhancement by squeezing light into a nanoscale gap. These optical hotspots are highly attractive for boosting nonlinear processes, such as harmonic generation, photoelectron emission, and ultra…
View article: Coherent Control of the Nonlinear Emission of Single Plasmonic Nanoantennas by Dual‐Beam Pumping (Advanced Optical Materials 20/2022)
Coherent Control of the Nonlinear Emission of Single Plasmonic Nanoantennas by Dual‐Beam Pumping (Advanced Optical Materials 20/2022) Open
An asymmetric plasmonic nanoantenna mediates the nonlinear mixing between ultrashort infrared laser pulses at frequency ω and 2ω. The third harmonic at ω + ω + ω and the sum frequency at ω + 2ω are coherent and degenerate at the visible fr…
View article: Coherent Control of the Nonlinear Emission of Single Plasmonic Nanoantennas by Dual‐Beam Pumping
Coherent Control of the Nonlinear Emission of Single Plasmonic Nanoantennas by Dual‐Beam Pumping Open
The control of nonlinear optical signals in nanostructured systems is pivotal to develop functional devices suitable for integration in optical platforms. A possible control mechanism is exploiting coherent interactions between different n…
View article: The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication
The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication Open
Focused beams of helium ions are a powerful tool for high-fidelity machining with spatial precision below 5 nm. Achieving such a high patterning precision over large areas and for different materials in a reproducible manner, however, is n…
View article: Experimental investigation of new optical antenna designs found by a genetic algorithm
Experimental investigation of new optical antenna designs found by a genetic algorithm Open
Most currently studied optical antenna geometries are based on radio wave antenna designs. However, material properties at optical frequency largely differ from the perfect metal case at radio frequencies. Recently, evolutionary algorithms…
View article: Nanoantennae on AFM-Tips for enhanced fluorescence detection
Nanoantennae on AFM-Tips for enhanced fluorescence detection Open
To investigate the enhanced light-matter interaction mediated by optical nanoantennas, there is a need for reliable quantum emitters (QE). Nanodiamonds (ND) with N-V-centers and single-walled carbon nanotubes (SWCNT) are a good choice, sin…
View article: Resonant behavior of a single plasmonic helix: supplementary material
Resonant behavior of a single plasmonic helix: supplementary material Open
Supplemental document
View article: Mode Matching for Optical Antennas
Mode Matching for Optical Antennas Open
The emission rate of a point dipole can be strongly increased in the presence of a well-designed optical antenna. Yet, optical antenna design is largely based on radio-frequency rules, ignoring, e.g., Ohmic losses and non-negligible field …
View article: Plasmonic nanoantenna design and fabrication based on evolutionary optimization
Plasmonic nanoantenna design and fabrication based on evolutionary optimization Open
Nanoantennas can tailor light-matter interaction for optical communication, sensing, and spectroscopy. Their design is inspired by radio-frequency rules which partly break down at optical frequencies. Here we find unexpected nanoantenna de…
View article: Electromechanically Tunable Suspended Optical Nanoantenna
Electromechanically Tunable Suspended Optical Nanoantenna Open
Coupling mechanical degrees of freedom with plasmonic resonances has potential applications in optomechanics, sensing, and active plasmonics. Here we demonstrate a suspended two-wire plasmonic nanoantenna acting like a nanoelectrometer. Th…
View article: New insights into colloidal gold flakes: structural investigation, micro-ellipsometry and thinning procedure towards ultrathin monocrystalline layers
New insights into colloidal gold flakes: structural investigation, micro-ellipsometry and thinning procedure towards ultrathin monocrystalline layers Open
High-quality fabrication of plasmonic devices often relies on wet-chemically grown ultraflat, presumably single-crystalline gold flakes due to their superior materials properties. However, important details about their intrinsic structure …