Related papers: Optical superradiance from single-digit-femtosecon…
The Fractional Fourier Transform (FRT) corresponds to an arbitrary-angle rotation in the phase space, e.g. the time-frequency (TF) space, and generalizes the fundamentally important Fourier Transform. FRT applications range from classical…
Terahertz pulse generation by ultra-intense two-color laser fields ionizing gases with near- to far-infrared carrier wavelength is studied from particle-in-cell (PIC) simulations. For long wavelength ($10.6\ \mu$m) promoting a large ratio…
The terahertz spectral regime, ranging from about 0.1 to 15 THz, is one of the least explored yet most technologically transformative spectral regions. One current challenge is to develop efficient and compact terahertz emitters/detectors…
We report on fluctuations in the electron system, Cooper pairs and quasiparticles, of a superconducting aluminium film. The superconductor is exposed to pair-breaking photons (1.54 THz), which are coupled through an antenna. The change in…
We report a proof-of-concept demonstration of a tunable infrared (IR) optical coherence tomography (OCT) technique with detection of only visible range photons. Our method is based on the nonclassical interference of frequency correlated…
We report a combined theoretical and experimental study of the spectral and polarization dependence of near resonant radiation coherently backscattered from an ultracold gas of 85Rb atoms. Measurements in an approximately 6 MHz range about…
We describe a method that uses Optical Transition Radiation (OTR) screens to measure in a single shot the emittance of an electron beam with an energy greater than 100 MeV. Our setup consists of 4 OTR screens located near a beam waist. A…
We demonstrate a versatile technique for generating continuously wavelength-tunable laser waveforms, with mJ pulse energies and ultrashort pulse durations down to few-cycle in the ultraviolet C and visible spectral ranges. Using the…
Narrow-band THz coherent Cherenkov radiation can be driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. We present a scheme of compact THz radiation source based on the…
Super- and subradiance are usually described in the framework of Dicke collective states, which is an ``atomic picture'' in which the electromagnetic field only provides an effective interaction between the atoms. Here, we discuss a…
Dedicated optics with extremely short electron bunches enable synchrotron light sources to generate intense coherent THz radiation. The high degree of spatial compression in this so-called low-alpha optics entails a complex longitudinal…
Terahertz (THz) emission by two-color, ultrashort optical pulses interacting with underdense helium gases at ultrahigh intensities ($> 10^{19}\,\mathrm{W/cm}^2$) is investigated by means of 3D particle-in-cell simulations. The THz field is…
We report the observation of all-optically tunable Raman fluorescence from a single quantum dot. The Raman photons are produced in an optically-driven Lambda-system defined by subjecting the single electron charged quantum dot to a magnetic…
Supercontinuum generation (SCG) with spectral coverage across the full visible and ultraviolet (UV) ranges is crucial for optical clocks, quantum computing and sensing. However, achieving such SCG in nanophotonic platforms is challenging…
We demonstrate narrowband orthogonally polarized optical RF single sideband generation as well as dual-channel equalization based on an integrated dual-polarization-mode high-Q microring resonator. The device operates in the optical…
The feasibility to generate correlated photon pairs at variable frequencies is investigated. For this purpose, we consider the interaction of an off-resonant laser field with a two-level system possessing broken inversion symmetry. We show…
The radiation of photons by electrons is investigated in the framework of quantum electrodynamics up to the second order in the coupling constant $e$. The $N$-particle, coherent, and thermal initial states are considered and the forms of…
In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons…
Using aluminum-nitride photonic-chip waveguides, we generate optical-frequency-comb supercontinuum spanning from 500 nm to 4000 nm with a 0.8 nJ seed pulse, and show that the spectrum can be tailored by changing the waveguide geometry.…
Thermal photons from the photosphere may be the primary source of the observed prompt emission of gamma-ray bursts (GRBs). In order to produce the observed non-thermal spectra, some kind of dissipation mechanism near the photosphere is…