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Electro‐optic sampling has emerged as a new quantum technique enabling measurements of electric field fluctuations on subcycle time scales. In a second‐order nonlinear material, the fluctuations of a terahertz field are imprinted onto the polarization properties of an ultrashort probe pulse in the near infrared. The statistics of this time‐domain signal are calculated, incorporating the quantum nature...
A high‐power femtosecond Yb:fiber system is seeded by a phase‐locked Er:fiber source and drives an ultra‐broadband optical parametric amplifier that operates at 10 MHz repetition rate. The resulting pulses display precise control of the carrier‐envelope phase. Their 8.3 fs temporal duration corresponds to 2.3 optical cycles of the 1100 nm carrier wavelength. Focusing 200 nJ of pulse energy into widegap...
We experimentally demonstrate tunable, phase-matched difference frequency generation fully covering the spectral regime below 15 THz using 4H-SiC as nonlinear crystal. The material is also exploited as a broadband detector for electro-optic sampling.
An order-of-magnitude enhancement in the radiative recombination rate is observed in single CdSe/CdS/PMMA colloidal quantum dots when coupled to gold plasmonic resonators, consistent with the measured increase in the excitonic photoluminescence signal.
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.
We study the carrier-envelope phase noise of an Er:fiber frequency comb which is passively phase-locked at the full repetition rate of 100 MHz. A novel characterization method determines an out-of-loop phase jitter of only 250 mrad when integrated over 12 orders of magnitude: from 50 μHz up to the Nyquist frequency.
Label-free optical microscopy plays an important role in biological research. Coherent Raman microscopy combines three-dimensional resolution and fast image acquisition with molecular selectivity based on the vibrational spectrum of the sample. During the last years stimulated Raman scattering (SRS) microscopy has become an important technique in this framework since it does not display an electronic...
Dual-wavelength and tri-wavelength operation of solid-state lasers has been attracting a great deal of attention, due to the need for such sources in applications like coherent terahertz generation [1]. Multicolor laser operation has been shown in many solid-state laser gain media including Nd:YAG, Yb:KGW, Tm:YAP, Cr:LiSAF, Alexandrite, Tm:CaYAlO4, and Ti:Sapphire. Most of the earlier studies report...
Laser operation of Nd+3-doped gadolinium scandium gallium garnet (Nd:GSGG) has been first shown by Kaminskii et al. in 1976 [1]. In earlier studies, flaslamp or solar pumping of Nd:GSGG has been explored, and narrow absorption bands of the Nd+3 ion, that overlaps poorly with these broadband emitters resulted in low laser efficiencies. As a solution, co-doping with chromium ion (Cr:Nd:GSGG) has been...
Quantum field theory offers the most exact description of the physics of microscopic interactions. The process offield quantization necessitates the existence of a vacuum field with a corresponding zero-point energy [1]. From this point of view, the ability to directly measure and manipulate electrodynamic quantum vacuum field is an attractive prospect for experimental physics. It is bound to shed...
Applications of optical frequency combs in high precision metrology [1] require low-noise stabilization of its carrier-envelope offset (CEO) frequency. This task is commonly achieved via active feedback. Fully passive elimination of the CEO frequency based on difference frequency generation (DFG) between two octave-separated comb sections followed by amplification of the DFG signal in the EDFA has...
By accessing the nonperturbative strong-field regime, light-matter interaction is governed by the electric field transient of light as opposed to multiphoton effects. In our experiments, we illuminate a circuit with a nanoscale open junction (Fig. 1(a)) with intense ultrashort pulses at high repetition rate. With this setup, we are able to coherently drive electronic currents at optical frequencies...
The frequency range between 5 THz and 15 THz is a spectral region of particular interest since it includes various fundamental excitations in condensed-matter systems such as phonons in solids, molecular vibrations and low-energy collective modes of correlated materials. However, the generation and coherent detection of highly stable THz transients for ultrafast experiments in this spectral interval...
Generation of ultrashort and intense laser pulses is the primary motive in ultrafast and nonlinear science. Unfortunately, only a limited number of active media allows for scaling ultrashort pulses to energies greater than a few mJ at kHz repetition rate. For this reason, the available wavelengths are extremely restricted. To drive ultrafast processes in novel frequency domains, the ideal approach...
Polymer-capped colloidal semiconductor quantum dots [1] offer a robust material system for time-resolved analysis and individual control of ultrafast charge carrier dynamics [2]. This goal necessitates a strong enhancement of light-matter interaction. In this work we demonstrate an efficient coupling of individual CdSe/CdS/PMMA quantum dots (QDs) to plasmonic resonators formed out of multiple concentric...
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 [1].
Optical nanoantennas are excellent tools for accessing the nonlinear response of noble metals owing to the strong enhancement of light-matter interaction occurring in the near-field. For example, excitation of gold nanostructures with intense radiation triggers both coherent and incoherent phenomena such as third-harmonic generation (THG) [1] and multi-photon photoluminescence (MPPL), respectively...
Generation of optical harmonics is an appealing research area due to the prospect of table-top light sources in the extreme ultraviolet and generation of attosecond pulses [1]. Excitation of harmonics in solids shows intrinsic differences compared to the process in gases and has yet to be fully explained [2]. In addition, such experiments are likely to provide fundamental insights into the electronic...
We demonstrate carrier-envelope phase control of even and odd harmonics in solids up to fifth order with intense 2.3-cycle pulses from a near-infrared optical parametric amplifier operated at 10 MHz repetition rate.
Combined Er/Yb:fiber and Yb:thin-disk technology produces 615 fs pulses at 1030 nm with an energy of 17 mJ at 3 kHz repetition rate. The sub-ps duration allows efficient white-light generation and optical parametric amplification.
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