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Dynamics of plasmonic vortices are observed using time-resolved two-photon PEEM (40 nanometers, 100 attoseconds resolution). The measured orbital angular momentum surprisingly differs from theory due to the observation from the rotating frame of circular polarization.
We experimentally reveal the sub-optical cycle dynamic formation, revolution and decay of plasmonic vortices using time-resolved two-photon photoemission electron microscopy with <30 nanometers lateral and 100 atto-seconds time-step resolution. The combination of spin and angular momentum results in surprising vortex formations.
In this work we use a hybrid geometrical and wave-optical approach to design and simulate stacked microlenses with varying fields of view. After 3D printing, an excellent agreement of simulated and measured imaging performance is found.
We present powerful alternatives to the “classical” optical parametric oscillator for frequency conversion of ultrafast pulses at high repetition rate. Applications of these sources to stimulated Raman scattering microscopy and high-brilliance Fourier-transform infrared spectroscopy are demonstrated.
We investigate the spatiotemporal characteristics of subpicosecond pulse propagation in the nonlinear defocusing regime below the band edge of bulk GaAs. We observe temporal and spatial pulse compression and instabilities.
A theoretical approach to the description of semiconductor near-field optics is presented. Starting from the microscopic light-matter interaction, the equations of motion for the relevant observables are derived and analyzed. Selected applications include optical near-field distributions in mesoscopic semiconductor structures, near-field selection rules and spatio-temporal wavepacket dynamics.
We combine surface-enhanced infrared absorption and a high brilliance optical parametric light source to enable ultra-sensitive and fast Fourier-transform infrared spectroscopy of only 10 000 molecules; inaccessible with conventional thermal light sources or synchrotron radiation.
In this contribution, a method to select discrete wavelengths that allow an accurate estimation of the glucose concentration in a biosensing system based on metamaterials is presented. The sensing concept is adapted to the particular application of ophthalmic glucose sensing by covering the metamaterial with a glucose-sensitive hydrogel and the sensor readout is performed optically. Due to the fact...
We present a novel concept for ophthalmic glucose sensing using a biosensing system that consists of plasmonic dipole metamaterial covered by a layer of functionalized hydrogel. The metamaterial together with the hydrogel can be integrated into a contact lens. This optical sensor changes its properties such as reflectivity upon the ambient glucose concentration, which allows in situ measurements in...
In the radiofrequency domain wireless signal transfer with antennas instead of cable connections has led to a plethora of new applications. In the optical regime, however, free-space signal transfer on the nanoscale using plasmonic antennas has so far only been proposed theoretically [1].
Embedding a single quantum emitter in an artificial nanostructure allows engineering the optical properties of the emitter. Plasmon resonant structures are particularly interesting for this purpose, as they allow confining electromagnetic fields to the nanoscale. This results in highly modified light-matter interaction. The extreme field localization requires the plasmonic structure to be positioned...
Assessing the near-field distribution of plasmonic nanoantennas offers fundamental insight into light-matter coupling. In particular resonantly enhanced near-field intensities in the IR and THz region are important since the molecular fingerprints of various molecules are situated in this spectral domain.
We directly map plasmonic near-field intensities by resonantly enhanced infrared far-field spectroscopy. We position a nanoscopic molecular probe at different locations of plasmonic rod and gap-type antennas and measure the vibrational signal with FTIR spectroscopy.
We perform third harmonic spectroscopy of complex plasmonic nanoantennas which exhibit EIT-like Fano resonances in their linear extinction spectrum. Strong third harmonic emission is found at the lower energy mode of the coupled plasmonic system.
We demonstrate a chiral optical response in stacked arrangements of resonantly coupled plasmonic nanostructures possessing the capability to encode their 3D arrangement in unique spectra making then ideal candidates for a 3D chiral plasmonic ruler.
We present the classical analog of electromagnetically induced absorption which is achieved by tuning the coupling phase between a bright and a dark plasmonic resonance in the intermediate regime and thus obtaining constructive interference.
The light emission properties of a single quantum system may be significantly modified by placing the emitter close to a nanostructure. Plasmon resonant metal structures are particularly interesting as the electromagnetic field may be significantly enhanced at the plasmon resonance. This allows controlling, e.g., the excitation and emission rate [1] as well as the emission pattern of the emitter [2],...
We introduce a novel concept to plasmonic sensing. Specifically, we demonstrate a perfect narrow-band plasmonic absorber, which allows for the extremely sensitive detection of the concentration change of glucose solution at a fixed frequency.
We experimentally demonstrate a nanoplasmonic analog of electromagnetically induced transparency utilizing a stacked optical metamaterial. Specifically, we achieve a very narrow transparency window with high modulation depth due to nearly complete suppression of radiative losses.
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