Related papers: Bright, Coherent, Ultrafast Soft X-Ray Harmonics S…
This Letter brings together two topics that, until now, have been the focus of intense but non-overlapping research efforts. The first concerns high harmonic generation in solids, which occurs when intense light field excites highly…
We report strong terahertz (~10^12 Hz) high harmonic generation in thin films of Cd3As2, a three-dimensional Dirac semimetal at room temperature. The third harmonics is detectable with tabletop light source and can be as strong as 100 V/cm…
High harmonic spectra generated in condensed matter carry the fingerprints of sub-cycle electronic motion and the energy structure of the studied system. Here we show that tailoring the waveform of mid-infrared driving light by using a…
High harmonic emissions from crystalline solids contain rich information on the dynamics of electrons driven by intense infrared laser fields and have been intensively studied owing to their potential use as a probe of microscopic…
We observe a new regime of coherent XUV radiation generation in noble gases induced by femtosecond pulses at very high intensities. This XUV emission has both a reduced divergence and spectral width as compared to high-order harmonic…
The basic properties of atoms, molecules and solids are governed by electron dynamics which take place on extremely short time scales. To measure and control these dynamics therefore requires ultrafast sources of radiation combined with…
Paraxial light skyrmions are topological configurations that map a spatial domain of the field onto the full Poincar\'e sphere of polarization states. While optical skyrmions have been explored in continuous-wave regimes, their realization…
We report the generation of biphotons, with a temporal full width at the half maximum (FWHM) of 13.4$\pm$0.3 $\mu$s and a spectral FWHM of 50$\pm$1 kHz, via the process of spontaneous four-wave mixing. The temporal width is the longest, and…
Thermotropic liquid crystals are versatile optical materials that exhibit a state of matter intermediate between liquids and solids. Their properties can change significantly with temperature, pressure, or other external factors, leading to…
We investigate second and third harmonic generation in a slab of material that displays plasma resonances at the pump and its harmonic frequencies. Near-zero refractive indices and local field enhancement can deplete the pump for kW/cm2…
We review the current state of tabletop extreme ultraviolet (XUV) sources based on high harmonic generation (HHG) in femtosecond enhancement cavities (fsEC). Recent developments have enabled generation of high photon flux (1014 photons/sec)…
Resonances in the photo-absorption spectrum of the generating medium can modify the spectrum of high order harmonics. In particular, window-type Fano resonances can reduce photo-absorption within a narrow spectral region and, consequently,…
X-ray phase-contrast imaging has recently led to a revolution in resolving power and tissue contrast in biomedical imaging, microscopy and materials science. The necessary high spatial coherence is currently provided by either large-scale…
The development of extreme ultraviolet sources is critical for advancing angleresolved photoemission spectroscopy (ARPES), a powerful technique for probing the electronic structure of materials. Here, we report the construction of a…
High harmonic generation by relativistically intense laser pulses from overdense plasma layers is surveyed. High harmonics are generated in form of (sub-)attosecond pulses when the plasma surface rebounds towards the observer with…
The recurrent hard pulsating X-ray transient \S was observed with \B on March 19, when the source was at a 2--10 keV flux level of $\sim$310~mCrab. We report on the high energy spectrum of the source, concentrating on cyclotron resonant…
We study the spontaneous emission, the absorption and dispersion properties of a ${\bf \Lambda}$-type atom where one transition interacts near resonantly with a double-band photonic crystal. Assuming an isotropic dispersion relation near…
The development of attosecond technology has enabled the real-time observation of coherent electron motion in atoms, molecules and condensed phases. Experimentally, it is now possible to generate laser pulses of durations of only a few tens…
The Galactic diffuse soft gamma-ray (30-800 keV) emission has been measured from the Galactic Center by the HIREGS balloon-borne germanium spectrometer to determine the spectral characteristics and origin of the emission. The resulting…
High harmonic generation (HHG) from gas phase atoms (or molecules) has opened up a new frontier in ultrafast optics, where attosecond time resolution and Angstrom spatial resolution are accessible. The fundamental physical pictures of HHG…