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Ultrashort light pulses have strong research and application values, while nonlinear inverse Thomson scattering has been considered as a unique source of zepto-yoctosecond pulses. Here, the mechanism of nonlinear inverse Thomson scattering of a high-energy electron colliding with a tightly focused intense laser pulse is investigated through numerical simulation. The time-compression effect was proposed to explain the origin of ultrashort pulses and the nonlinear phenomenon of electron radiation in the time–space joint distribution. It is found that the time scale of electron radiation is orders of magnitude shorter than that of electron motion, and the increases in laser intensity and electron initial energy will result in stronger and shorter pulses. Yoctosecond pulses can be generated by a laser pulse with an intensity of 1.384 × 10 20   W / c m 2 and an electron with an initial energy of 51.1   M e V . These results provide theoretical and numerical basis for generating shorter light pulses. [ABSTRACT FROM AUTHOR]

In this paper, two parameters of the applied magnetic field—magnetic field strength and pulse length—are modified, the spatial properties of electron trajectories and radiation are studied, and conclusions are drawn. Under the premise that the radius of the laser pulse waist b 0 = 4 λ 0 , and that the peak amplitude a 0 = 5 corresponds to the peak laser intensity I L = 3.45 × 10 19   W / c m 2 of the electrons, obtaining high-energy and highly collimated X-rays can be realized by increasing the pulse length up to 6 λ 0 and increasing the magnitude of the applied magnetic field, or by continuously increasing the pulse length and applying a smaller magnetic field. [ABSTRACT FROM AUTHOR]

This article delves into the generation and modulation process of X-rays as high-energy photon sources. Using the principles of classical electrodynamics, this study enables nonrelativistic short pulse lasers to collide with high-energy electrons while the collision center is away from the focal point. This scattering method may produce X-rays with good collimation and monochromaticity, and it progressively approaches inverse Thomson scattering. We studied and analyzed the effects of different electron characteristics and laser parameter settings on the high-energy angular distribution and spectrum of X-rays, especially the setting of the collision center and initial electron velocity, as well as the setting of laser intensity and pulse width. Linear polarized laser pulses with relativistic intensity can generate discrete supercontinuum X-rays with spectral distortion. In addition, the relationships between electronic and laser properties and radiation energy were also studied. Our research can provide valuable insights for manipulating collimated or distorted, monochromatic, or tunable X-rays, as well as understanding their properties. [ABSTRACT FROM AUTHOR]

Based on the scalar diffraction theory, the propagation and focusing properties of a hard-edged diffracted beam generated by a Gaussian mirror resonator were investigated. Explicit expressions for the field distribution of the truncated beam that propagates through a paraxial optical ABCD system were derived in detail. Numerical examples are given to illustrate our analytical results. OCIS codes: 050.1960, 140.3300, 050.1220, 000.4430.

The far-field intensity distribution (FFID) of a beam generated by a phase-unifying mirror resonator was investigated based on scalar diffraction theory. Attention was paid to the parameters, such as obscuration ratio and reflectivity of the phase-unifying mirror, that determine the FFID. All analyses were limited to the [TEM.sub.00], fundamental mode. OCIS codes: 000.4430, 140.3300. 140.4780, 260.1960, 350.5500.

Osteosarcoma is among the commonly observed malignancies worldwide. High-mobility group box 1 protein (HMGB1) is a highly conserved protein and is involved in the progression of various types of human cancer. The aim of the present study was to explore whether the level of HMGB1 was involved in the necrosis of osteosarcoma cells. Doxorubicin (DXR), as an inducer of necrosis, was administered to human osteosarcoma cell lines (MG63, Saos-2 and U2OS), and the results indicated that 0.5 µg/ml DXR significantly induced the necrosis of MG63 cells (P<0.01), while 0.5 and 1.0 µg/ml DXR suppressed the viability of MG63 and U2OS cells (P<0.05), relative to untreated controls. Additionally, treatment with DXR was observed by western blot analysis to markedly increase the expression levels of HMGB1 in MG63 cells, and to significantly increase the levels of secreted HMGB1 in the supernatants of MG63 and U2OS cells (P<0.01). In conclusion, cell necrosis increased the level of HMGB1 in osteosarcoma cells, as well as the level of secreted HMGB1 in cell supernatants. Therefore, HMGB1 may be a potential target in molecular therapy for patients with osteosarcoma. [ABSTRACT FROM AUTHOR]

The use of high-energy radiation generated by electron collisions with a laser pulse is an effective method to treat cancer. In this paper, the spatial properties of radiation produced by electron collisions with a tightly focused linearly polarized laser pulse are investigated. Theoretical derivations and numerical simulations within the framework of classical electrodynamics show that the stronger the laser intensity, the higher the initial electron energy, and the longer the laser pulse, which can produce greater radiation power. An increase in the laser intensity expands the range of electron radiation and therefore reduces the collimation of the radiation. The collimation in the radiation is better when colliding with an electron of higher initial energy. The phenomenon that the radiated power of the electron varies periodically with the initial phase of the laser is also found. The results of this paper have important implications to produce strongly radiating and highly collimated rays.