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Using intense, few-cycle THz pulses we investigate the strong-field interaction with polarons in La0.7Ca0.3MnO3. By probing the optical reflectivity, we observe a THz-induced detrapping of electrons from polarons, followed by thermalization of phonons with spins.
We present a THz source providing multi-octave as well as narrowband spectra at electric field up to tens MV/cm. The emission is tunable in frequency over 0.5–8 THz and in relative bandwidth over 2%–300%.
We present time-resolved photo-induced plasmonic response in Bi2Se3 topological insulator investigated by means of optical-pump/THz-probe spectroscopy. We have found that topological insulators offer a non-trivial relaxation dynamics due to their complex bulk-surface interactions.
We report on a novel, simple and efficient THz energy and intensity profile diagnostic tool which is based on the photo-thermo-acoustic (PTA) effect in a 3-dimensional graphene sponge.
Fourier transform (FT) spectroscopy [1] is a powerful technique to measure spectra in the time domain. With respect to frequency-domain spectrometers, FT spectrometers have the advantage of higher signal to noise ratio and optical throughput, and the possibility to adjust the frequency resolution. FT spectroscopy requires to generate two field replicas whose delay must be scanned with accuracy of...
We demonstrate that THz radiation can be transduced into acoustic waves in three-dimensional graphene (3D) sponge material through a photo thermal-acoustic (PTA) mechanism. The presented photo-acoustic converter has the unique ability to turn efficiently electromagnetic waves into heat and sound. The unique combination of thermal, mechanical and electronic properties of graphene sheets arranged in...
The exploration of high field phenomena in the THz frequency range (0.1–10 THz) requires advanced THz laser technology to cope with the requirements of versatile source to drive either non-resonant or selective dynamics [1, 2]. Here we present a laser-based THz source which is able to provide both intense single-cycle pulses up to 50 MV/cm as well as narrowband radiation at MV/cm field strength tunable...
We report on a commercial, industrial-grade, sub-200 fs Yb-doped oscillator at 1041.3 nm central wavelength with an output power of 152 mW at 71.4 MHz repetition rate. The compact laser oscillator combines ultra-low amplitude and time jitter noise and it is well suited for seeding high-energy Yb-based amplifier systems. This technology developed for optical clocks and extended to this wavelength range...
Ultrastrong Terahertz (THz) transients have the potential to control instantaneously macroscopic properties of the matter [1-2]. By employing our recently developed THz bullet configuration [3, 4] with electric and magnetic field strength overpassing GV/m and few Tesla we demonstrated THz-driven ultrafast electronic and magnetic dynamics [5, 6]. Here we report on the experimental observation of extreme...
Plasmons are collective charge density waves in a conductive material, which show remarkable electromagnetic properties and have great potential for photonics from terahertz to the ultraviolet. Besides the conventional plasmonic excitations in metals and in semiconductors, 2-dimensional (2D) plasmons of massless Dirac electrons have been observed in graphene and at the surface of topological insulators...
Present THz source technology, with peak fields > 1 GV/m, are realized by optical rectification (OR) of femtosecond pulses in organic crystals [1-3]. The main challenge for such source is the need of high-energy pump laser at non-standard wavelengths (1.2–1.5 μm) for the optimal phase matching conditions. Ti:sapphiredriven optical parametric amplifiers are the most common technique to shift the...
We study the interaction of intense THz magnetic fields with ferromagnetic thin films. At higher field intensities, the THz electric field starts playing a role, strongly changing the dielectric properties of the cobalt thin film.
We report on measurements of the instantaneous Kerr nonlinearity and the retarded alignment of non-polar molecules CO2, N2, and O2 by an intense, lambda-cubic terahertz pulse with peak field >33 MV/cm centered at 3.9 THz.
Low frequency THz radiation is visualized on common optically-designed CCD and CMOS sensors. The CCD/CMOS technology offers smallest pixel size, large chip, very cheap cost, insensitivity to background noise, and multispectral detection.
High-energy pulses at 1.28 μm are demonstrated by stimulated Raman scattering using two chirped pulses of a Ti:Sapphire laser in hydrogen. The Stokes pulse carrying record-high energy of 4.4 mJ is recompressed to 80 fs.
We show that triangular selenium has excellent phase matching for THz generation through optical rectification in the range 0.1–4 THz. The performance exceeds that of the state-of-the-art organic crystals.
We present giant cross phase modulation of a 60 fs nIR pulse in GaP by means of an intense Terahertz transient. The THz field induces up to 500% spectral broadening supporting sub-10 fs nIR pulses.
Low frequency THz radiation is visualized by means of a charged-coupled device designed for optical frequencies and a CMOS sensor. This technological advance opens novel opportunities in THz imaging as it offers smallest pixel size and large chip size at low cost. Furthermore the sensor is insensitivity to background noise and is able to detect radiation of multiple spectral ranges from x-rays to...
We present giant spectral broadening by cross phase modulation of a 60 fs nIR pulse in GaP by means of an intense Terahertz transient. The THz field induces up to 500% spectral broadening supporting sub-10 fs nIR pulses.
High-energy pulses at 1.28 μm are demonstrated by stimulated Raman scattering in hydrogen using two chirped pulses of a Ti: Sapphire laser. The Stokes pulse carrying record-high energy of 4.4 mJ is recompressed to 80 fs.
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