Asymmetric pulse effects on pair production in polarized electric fields

Abstract

Using the Dirac–Heisenberg–Wigner formalism, effects of the asymmetric pulse shape on the generation of electron-positron pairs in three typical polarized fields, i.e., linear, middle elliptical and circular fields, are investigated. Two kinds of asymmetries for the falling pulse length, short and elongated, are studied. We find that the interference effect disappears with the shorter pulse length and that the peak value of the momentum spectrum is concentrated in the center of the momentum space. In the case of the extending falling pulse length, a multiring structure without interference appears in the momentum spectrum. Research results show that the momentum spectrum is very sensitive to the asymmetry of the pulse as well as to the polarization of the fields. We also find that the number density of electron-positron pairs under different polarizations is sensitive to the asymmetry of the electric field. For the short falling pulse, the number density can be significantly enhanced by over two orders of magnitude. These results could be useful in planning high-power and/or high-intensity laser experiments.

Dispersion management for a 100 PW level laser using a mismatched-grating compressor

“…The SEL-100 PW laser facility was started in 2018 [14] , aiming at investigations of strong field quantum electrodynamics, vacuum birefringence and positron-electron pair generation from vacuum [31][32][33] , based on collisions with intense hard X-ray lasers. As shown in Figure 1, the SEL-100 PW laser facility mainly consists of a high-contrast laser seed source, a double-grating Offner stretcher, three lithium triborate (LBO)-based OPCPA power amplifiers, two DKDP-based OPCPA high-energy main amplifiers and a Treacy compressor.…”

“…The SEL-100 PW laser facility was started in 2018 [14], aiming at the investigations of strong field quantum electrodynamics, vacuum birefringence and the positron-electron pair generation from vacuum [32][33][34], based on the collisions with intense hard X-ray lasers. As shown in Fig.…”

Broadband convolutional scattering characteristics of all dielectric transmission Pancharatnam–Berrygeometric phase metasurfaces

“…Assuming that the transmission phase of the unit (m, n) is φ (m, n), when a plane wave is incident perpendicularly on an encoding metasurface, the far-field transmission of the surface can be expressed as [26] (1) where the wave vector k 0 = λ /2π, φ is the azimuth, f e (θ, φ) indicates the radiation direction of the unit structure, and P stands for unit structure size. The above formula can be further simplified to (2) Here, φ m is the phase of the horizontal encoding unit; φ n is the phase of the encoding unit in the vertical direction. From Eqs.…”

“…The metasurface can be regarded as the two-dimensional corresponding structure of the metamaterial, which is an artificial layered anisotropic quasi-periodic structure array with a wavelength smaller than the thickness [1][2][3][4][5][6][7][8][9][10]. Metasurfaces have some extraordinary physical properties that are not found in materials in nature [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Transmission electromagnetic beam splitter based on double-sided all dielectric microstructure

“…In traditional three-dimensional metamaterials, electromagnetic wave continuously propagates inside the metamaterial to modulate the amplitude and phase of the beam [1][2][3][4][5][6][7][8][9][10]. In this process, it is easy to cause a large loss of incident energy, and introduce unavoidable frequency and spatial dispersion.…”