Related papers: THz light source based on the two-stream instabili…
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…
Branched flow is an interesting phenomenon that can occur in diverse systems. It is usually linear in the sense that the flow does not alter the medium properties. Branched flow of light on thin films was recently discovered. A question of…
We propose a microscopic theory of terahertz (THz) radiation generation on metal gratings under the action of femtosecond laser pulses. In contrast to previous models, only low-frequency currents inside the metal are considered without…
Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broadband source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme of coherent diffraction-radiation in an…
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…
The terahertz (THz) generation in a dual-color field was investigated experimentally by precisely controlling the relative time delay $\tau$ and polarization $\theta$ of dual-color lasers, where the accompanying third-harmonic generation…
Electrically injected terahertz (THz) radiation sources are extremely appealing given their versatility and miniaturization potential, opening the venue for integrated-circuit THz technology. In this work, we show that coherent THz…
Narrow bandwidth, high energy photon sources can be generated by Thomson scattering of laser light from energetic electrons, and detailed control of the interaction is needed to produce high quality sources. We present analytic calculations…
The lowest-frequency Raman mode of water, observed through depolarized light scattering or optical Kerr effect techniques, is routinely used to track dynamic changes in water molecules near ions or biomolecules. Yet, the microscopic origin…
The spatial and spectral distributions of terahertz (THz) pulses emitted by two-color air plasmas are theoretically investigated for focused laser pulses and in the filamentation regime. We derive a so-called ''augmented'' conical emission…
Taking into account both the scattering and the velocity saturation of carriers, we examine the "shallow-water" instability of the two-dimensional electron gas in a field effect transistor. It is shown that both the scattering (which is…
A novel scheme is proposed to generate uniform relativistic electron layers for coherent Thomson backscattering. A few-cycle laser pulse is used to produce the electron layer from an ultra-thin solid foil. The key element of the new scheme…
In modern terahertz (THz) sensing and imaging spectroscopy, water is considered a nemesis to be avoided due to strong absorption in the THz frequency range. Here we report the first experimental demonstration and theoretical implications of…
The tremendous applications of terahertz (THz) spectroscopy and imaging require THz sources in different parameters. We propose a novel scheme to generate single-cycle powerful THz pulses by ultrashort intense laser pulses incident…
We propose a coupled microdisk laser as a compact and tunable laser source for the generation of a coherent continuous wave THz radiation by photomixing. Using the Schr\"odinger-Bloch model including the nonlinear effect of active medium,…
Experimental results of direct measurement of resonant monochromatic terahertz emission optically excited in InGaAs transistor channels are presented. The emission is attributed to two-dimensional plasma waves excited by photogeneration of…
High-power multi-color terahertz (THz) radiation exhibits extraordinary scientific application prospects at various scientific frontiers, for its capacity to deliver THz excitation at multiple frequencies simultaneously. However, the…
On the basis of an energy-recovery linac, a terahertz (THz) source with kilowatts average power is proposed in Shanghai, which will serve as an effective tool in material and biological sciences. In this paper, the physical design of two…
Anelastic light scattering is computed numerically for model disordered systems (linear chains and 2-dimensional site and bond percolators), with and without electrical disorder. A detailed analysis of the vibrational modes and of their…
The Raman effect -- inelastic scattering of light by lattice vibrations (phonons) -- produces an optical response closely tied to a material's crystal structure. Here we show that resonant optical excitation of IR and Raman phonons gives…