Related papers: Terahertz generation by beamlet superposition
We derive simple formulas to explain terahertz (THz) emission from semiconductor surfaces excited by a femtosecond (fs) laser. Femtosecond optical pulses with energies larger than the bandgap create photocarriers which travel and generate…
This paper presents an efficient approach for exciting a dielectric resonator antenna (DRA) in the terahertz frequencies by means of a graphene plasmonic dipole. Design and analysis are performed in two steps. First, the propagation…
We systematically study the pump-wavelength dependence of terahertz pulse generation in thin-film spintronic THz emitters composed of a ferromagnetic Fe layer between adjacent nonmagnetic W and Pt layers. We find that the efficiency of THz…
The production of broadband, terawatt terahertz (THz) pulses has been demonstrated by irradiating relativistic lasers on solid targets. However, the generation of extremely powerful, narrow-band, and frequency-tunable THz pulses remains a…
We introduce a new regime of cascaded quadratic nonlinearities which result in a continuous red shift of the optical pump, analogous to a Raman shifting process rather than self-phase modulation. This is particularly relevant to terahertz…
In the widely-studied two-color laser scheme for terahertz (THz) radiation from a gas, the frequency ratio of the two lasers is usually fixed at $\omega_2/\omega_1=$1:2. We investigate THz generation with uncommon frequency ratios. Our…
We detected broadband coherent terahertz (THz) emission from multiferroic BiFeO3 after illuminating a high-quality bulk single ferroelectric domain crystal with a ~100 fs optical pulse. The dependence of the emitted THz waveform on the…
Frequency multiplication of terahertz signals on a solid state platform is highly sought-after for the next generation of high-speed electronics and the creation of frequency combs. Solutions to efficiently generate extreme harmonics (up to…
Terahertz waves hold immense potential across diverse fields, including healthcare monitoring, biomedical imaging, precision navigation, high-speed communication, security screening, industrial quality control, and space exploration.…
The angular dependence of terahertz (THz) emission from birefringent crystals can differ significantly from that of cubic crystals. Here we consider optical rectification in uniaxial birefringent materials, such as chalcopyrite crystals.…
Spintronic THz emitters, consisting of Ta/Co/Pt trilayers patterned into rectangles of lateral size in the 10 ${\mu}$m range, have been integrated in planar electromagnetic antennas of various types (dipole, bow-tie, spiral). Antenna…
We analyze the electromagnetic field of a short relativistic electron beam propagating in a round, hollow dielectric channel. We show that if the beam propagates with an offset relative to the axis of the channel, in a steady state, its…
Equilibrium bunch lengths typical to modern day light sources of tens of picoseconds limit the spectral reach of superradiant approaches for exploring materials and biological samples. In particular, generation of terahertz radiation seems…
Numerical simulations of laser-plasma interactions demonstrate the generation of axially polarized electromagnetic pulses (EMPs) that radiate away energy with a characteristic frequency determined by the plasma frequency, in the THz range…
Ultrafast pump-probe technique is a powerful tool to understand and manipulate properties of materials for designing novel quantum devices. An intense, single cycle terahertz pulse can change the intrinsic properties of semiconductor…
Recent advances in deep learning have been providing non-intuitive solutions to various inverse problems in optics. At the intersection of machine learning and optics, diffractive networks merge wave-optics with deep learning to design…
Terahertz microscopy has attracted attention owing to distinctive characteristics of the THz frequency region, particularly non-ionizing photon energy, spectral fingerprint, and transparency to most nonpolar materials. Nevertheless, the…
Quantum entanglement is an important resource for next-generation technologies. We show that diffracting systems can supplant beam splitters, and more generally interferometric networks, for entanglement generation -- systems as simple as…
Novel mechanisms for electromagnetic wave emission in the terahertz (THz) frequency regime emerging at the nanometer scale have recently attracted intense attention for the purpose of searching next-generation broadband THz emitters. Here,…
A composite plasmonic slab based on double-layer metallic gratings and a dielectric film is experimentally and numerically demonstrated in terahertz (THz) regions, which can support two resonance modes and then form a broad bandgap (40%).…