Field-resolved detection of the temporal response of a single plasmonic antenna in the mid-infrared
2021, Fischer, Marco P., Maccaferri, Nicolò, Gallacher, Kevin, Frigerio, Jacopo, Pellegrini, Giovanni, Paul, Douglas J., Isella, Giovanni, Leitenstorfer, Alfred, Biagioni, Paolo, Brida, Daniele
Unveiling the spatial and temporal dynamics of a light pulse interacting with nanosized objects is of extreme importance to widen our understanding of how photons interact with matter at the nanoscale and trigger physical and photochemical phenomena. An ideal platform to study light–matter interactions with an unprecedented spatial resolution is represented by plasmonics, which enables an extreme confinement of optical energy into sub-wavelength volumes. The ability to resolve and control the dynamics of this energy confinement on the time scale of a single optical cycle is at the ultimate frontier towards a full control of nanoscale phenomena. Here, we resolve in the time domain the linear behavior of a single germanium plasmonic antenna in the mid-infrared by measuring the complex optical field response in amplitude and phase with sub-optical-cycle precision, with the promise to extend the observation of light–matter interactions in the time domain to single quantum objects. Accessing this fundamental information opens a plethora of opportunities in a variety of research areas based on plasmon-mediated photonic processes and their coherent control, such as plasmon-enhanced chemical reactions and energy harvesting.
Broadly tunable ultrafast pump-probe system operating at multi-kHz repetition rate
2018-01-01, Grupp, Alexander, Budweg, Arne, Fischer, Marco P., Allerbeck, Jonas, Soavi, Giancarlo, Leitenstorfer, Alfred, Brida, Daniele
Femtosecond systems based on ytterbium as active medium are ideal for driving ultrafast optical parametric amplifiers in a broad frequency range. The excellent stability of the source and the repetition rate tunable to up to hundreds of kHz allow for the implementation of an advanced two-color pump probe setup with the capability to achieve excellent signal-to-noise performances with sub-10 fs temporal resolution.
Coherent field transients below 15 THz from phase-matched difference frequency generation in 4H-SiC
2017-07-15, Fischer, Marco P., Bühler, Johannes, Fitzky, Gabriel, Kurihara, Takayuki, Eggert, Stefan, Leitenstorfer, Alfred, Brida, Daniele
We experimentally demonstrate tunable, phase-matched difference frequency generation covering the spectral region below 15 THz using 4H-SiC as a nonlinear crystal. This material combines a non-centrosymmetric lattice and strong birefringence with broadband transparency at low optical frequencies. Thorough refractive index measurements in the terahertz spectral range allow us to calculate phase-matching conditions for any near-infrared pump laser source. 4H-SiC is also exploited as a detector crystal for electro-optic sampling. The results allow us to estimate the effective second-order nonlinear coefficient.
Germanium plasmonic nanoantennas for third-harmonic generation in the mid infrared
2016-09, Fischer, Marco P., Riede, Aaron, Grupp, Alexander, Gallacher, Kevin, Frigerio, Jacopo, Ortolani, Michele, Paul, Douglas J., Isella, Giovanni, Leitenstorfer, Alfred, Brida, Daniele
Recent advances in semiconductor film deposition allow the growth of heavily doped germanium with effective plasma frequencies of up to 30 THz. This technology paves the way for mid-infrared (MIR) nanoplasmonics with application to integrated telecommunications systems and to precise sensing in the spectral region defined as the vibrational fingerprint of molecules. Characteristics like CMOS compatibility, low electron effective mass and tunable dielectric function give advantage to Ge over metal plasmonics or other semiconductors.
Field-Resolved Detection of the Temporal Response of a Mid-Infrared Plasmonic Antenna
2019, Fischer, Marco P., Gallacher, Kevin, Frigerio, Jacopo, Pellegrini, Giovanni, Isella, Giovanni, Leitenstorfer, Alfred, Paul, Douglas J., Biagioni, Paolo, Brida, Daniele
We performed electro-optic sampling of the pulses re-emitted by a heavily-doped germanium antenna resonant in the mid-infrared. This field-resolved measurement allows observing the time domain response of a single plasmonic structure in amplitude and phase.
Components for Integrated Ge on Si for Mid-Infrared Photonic Sensors
2018, Gallacher, Kevin, Millar, Ross W., Griskeviciute, Ugne, Fischer, Marco P., Riede, Aaron, Frigerio, Jacopo, Baldassarre, Leonetta, Pellegrini, Giovanni, Leitenstorfer, Alfred, Brida, Daniele
Components for mid-infrared chip-scale sensors are reviewed including loss measurements of Ge-on-Si waveguides between 8 and 10.5 μm wavelength. Third-harmonic generation is demonstrated using Ge nano-antennas. Such components are essential for a Ge-on-Si mid-infrared platform technology for healthcare, security and environmental sensing applications.
Mid-Infrared Third-Harmonic Emission from Heavily-Doped Germanium Plasmonic Nanoantennas
2017, Fischer, Marco P., Riede, Aaron, Grupp, Alexander, Gallacher, Kevin, Frigerio, Jacopo, Pellegrini, Giovanni, Ortolani, Michele, Isella, Giovanni, Leitenstorfer, Alfred, Brida, Daniele
We investigate the nonlinear optical properties of single resonant plasmonic antennas fabricated from heavily-doped Germanium films. Excitation with intense and ultrashort mid-infrared pulses at 10.8 µm wavelength produces emission at 3.7 µm via third-harmonic generation.
Plasmonic mid-infrared third harmonic generation in germanium nanoantennas
2018-12-12, Fischer, Marco P., Riede, Aaron, Gallacher, Kevin, Frigerio, Jacopo, Pellegrini, Giovanni, Ortolani, Michele, Paul, Douglas J., Isella, Giovanni, Leitenstorfer, Alfred, Brida, Daniele
We demonstrate third harmonic generation in plasmonic antennas consisting of highly doped germanium grown on silicon substrates and designed to be resonant in the mid-infrared frequency range that is inaccessible with conventional nonlinear plasmonic materials. Owing to the near-field enhancement, the result is an ultrafast, subdiffraction, coherent light source with a wavelength tunable between 3 and 5 µm, and ideally overlapping with the fingerprint region of molecular vibrations. To observe the nonlinearity in this challenging spectral window, a high-power femtosecond laser system equipped with parametric frequency conversion in combination with an all-reflective confocal microscope setup is employed. We demonstrate spatially resolved maps of the linear scattering cross section and the nonlinear emission of single isolated antenna structures. A clear third-order power dependence as well as mid-infrared emission spectra prove the nonlinear nature of the light emission. Simulations support the observed resonance length of the double-rod antenna and demonstrate that the field enhancement inside the antenna material is responsible for the nonlinear frequency mixing.
Dispersion of the nonlinear susceptibility in gold nanoantennas
2017-09-19, Knittel, Vanessa, Fischer, Marco P., Vennekel, Maike, Rybka, Tobias, Leitenstorfer, Alfred, Brida, Daniele
Femtosecond optical pulses tunable in the near infrared are exploited to drive third harmonic generation (THG) and incoherent multiphoton photoluminescence (MPPL) in gold plasmonic nanoantennas. By comparing the yield of the two processes concurrently occurring on the same nanostructure, we extract the coherent third-order response of the antenna. Its contribution is enhanced at shorter excitation wavelengths allowing the observation of dispersion in the nonlinear susceptibility of gold.
Germanium Nanoantennas for Plasmon-Enhanced Third Harmonic Generation in the Mid Infrared
2017, Fischer, Marco P., Riede, Aaron, Grupp, Alexander, Gallacher, Kevin, Frigerio, Jacopo, Pellegrini, Giovanni, Ortolani, Michele, Paul, Douglas J., Leitenstorfer, Alfred, Brida, Daniele
Recent advances in semiconductor film deposition allow for the growth of heavily-doped germanium with effective plasma frequencies above 60 THz, corresponding to wavelengths below 5 μm. This technology paves the way for mid-infrared nanoplasmonics with application in integrated telecommunication systems and enhanced molecular sensing in the so-called vibrational fingerprint spectral region . In this work, we demonstrate that Ge antenna structures are also suitable for nonlinear optical processes such as third harmonic generation (THG) in the mid infrared , owing to the strong resonant enhancement. Subwavelength-confined light emitters are of high interest for experiments targeting single molecules or other isolated quantum systems .