相关论文: THz emission from ultrafast optical orientation
We demonstrate that pulsed THz radiation produced in air by a focused ultrashort laser pulse can be steered to large angles or even in the backward direction with respect to the laser propagation axis. The emission angle is adjusted by the…
In past decades, ultrafast spin dynamics in magnetic systems have been associated with heat deposition from high energy laser pulses, limiting the selective access to spin order. Here we use a long wavelength terahertz pump optical probe…
We develop the microscopic theory of a terahertz (THz) laser based on the effects of resonant tunneling in a double quantum well heterostructure embedded in both optical and THz cavities. In the strong coupling regime the system hosts…
A significant step has been made towards understanding the physics of the transient surface current triggered by ejected electrons during the interaction of a short intense laser pulse with a high-conductivity target. Unlike the commonly…
We optically excite $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg state 10D$_{5/2}$ and observe directional terahertz (THz) beams at 3.3 THz and 7.8 THz. These THz fields are generated by amplified spontaneous emission from…
We directly observe longitudinal electromagnetic fields in focused freely propagating terahertz beams of radial and linear polarization. In accordance with theory, the longitudinal fields are phase shifted by a value of pi/2 with respect to…
Coherent phonon-polaritons have attracted a considerable amount of interest owing to their relevance to nonlinear optics and terahertz (THz)-wave emissions. Therefore, it is important to analyze the THz electric-fields of phonon-polaritons.…
The transport of relativistic electrons generated in the interaction of petawatt class lasers with solid targets has been studied through measurements of the optical emission from their rear surface. The high degree of polarization of the…
We explore properties of the radio-frequency atomic magnetometer, specifically its sensitivity to the polarisation of an oscillating magnetic field. This aspect can be particularly relevant to configurations where the sensor monitors fields…
Population of levels of the hyperfine and fine split ground state of an atom is affected by radiative transitions induced by anisotropic radiation flux. Such aligned atoms precess in the external magnetic field and this affects properties…
Radiative emission from a semi-infinite unflanged circular cylindrical dielectric waveguide or optical fiber is studied for the case of axisymmetric modes of TM polarization on the basis of an iterative scheme. The first step of the scheme…
We study THz-driven spin dynamics in thin CoPt films with perpendicular magnetic anisotropy. Femtosecond magneto-optical Kerr effect measurements show that demagnetization amplitude of about $1\%$ can be achieved with a peak THz electric…
We present a novel approach to model ultrafast time-dependent nonlinear optical polarization sensitive signals emitted from randomly-oriented molecules. By projecting the laboratory-frame analyzer polarization axis into the molecular frame…
Ultrafast laser pulses provide unique tools to manipulate magnetization dynamics at femtosecond timescales, where the interaction of the electric field -- such as excitation of spin carriers to non-equilibrium states, generation of…
We present an analytical method to study the angular distribution of THz radiation driven by two-color laser-induced microplasma in nitrogen gas. Directionally dependent temporal waveforms of the radiated THz pulse is calculated. To do so,…
We show that ionization of noble gas atoms by strong infrared circularly polarized laser field under standard exerimental conditions can yield electrons with up to 100% spin polarization in energy resolved measurements. Spin polarization…
We propose a method to generate isolated relativistic terahertz (THz) pulses using a high-power laser irradiating a mirco-plasma-waveguide (MPW). When the laser pulse enters the MPW, high-charge electron bunches are produced and accelerated…
Strong laser-induced magnetization of oxygen gas at room temperature and atmospheric pressure is achieved experimentally on the sub-nanosecond time scale. The method is based on controlling the electronic spin of paramagnetic molecules by…
The speed of magnetization reversal is a key feature in magnetic data storage. Magnetic fields from intense THz pulses have been recently shown to induce small magnetization dynamics in Cobalt thin film on the sub-picosecond time scale.…
We theoretically study the generation of terahertz (THz) radiation by two-color filamentation of ultrashort laser pulses with different wavelengths. We consider wavelengths in the range from 0.6 to 10.6 $\mu$m, thus covering the whole range…