Soft x-ray generation based on the two-plasmon decay and the backward Raman scattering in a moderately relativistic electron beam

掺杂等离子体金纳米棒的二甲基丙烯酸酯聚合物在单发高能飞秒激光辐照下形成的弹坑壁的拉曼光谱表征

Raman spectroscopic characterization of crater walls formed upon single-shot high energy femtosecond laser irradiation of dimethacrylate polymer doped with plasmonic gold nanorods

该研究通过拉曼光谱分析单发飞秒激光在掺金纳米棒聚合物中形成的弹坑壁，发现新的C–D/N–D振动峰，并推测其源于等离子体增强强激光场诱导的核反应。

Hybrid Stimulated Raman Scattering -- Two Plasmon Decay Instability and 3/2 Harmonic in Steep-Gradient Femtosecond Plasmas

The hybrid Stimulated Raman Scattering - Two Plasmon Decay instability had shown to play the dominant role for plasma waves excitation and energy absorption at interaction of very intense femtosecond obliquely incident $p$-polarized laser pulse (intensity $10^{17}-5\cdot10^{19}$ W/cm$^2$) with a steep gradient ($L\sim λ$) plasma near the quarter critical surface, i.e. within the typical for modern experiments conditions. The plasmons are excited as two wave packets confined near this surface with very wide $\approx ω_0/c$ spatial spectra along its normal. Hence, phase matching conditions for 3…

THz radiation using the two plasmon decay and the backward Raman scattering

A scheme of THz radiation using two moderately intense lasers and a moderately relativistic electron beam is proposed. In the scheme, a laser encounters a co-propagating relativistic electron beam, and excites plasmons via the two-plasmon decay. The excited plasmons will emit the THz radiations, interacting with the second laser via the Raman scattering. Our estimation suggests that the mena-free-path of the pump laser to the THz radiation is much shorter than the Thomson scattering. The physical parametes for practical interests are presented.

THz light source based on the two-stream instability and backward Raman scattering

A new scheme of the THz light source is proposed. The excitation of the Langmuir wave in a moderately relativistic electron beam via the two-stream instability and the subsequent interaction of the excited Langmuir wave with the visible light laser results in THz ligh via the Raman scattering. The cost of the current scheme could be cheaper than the conventional technologies by using the electron beam from cathodes and low-intensity infra-red laser.

Theory of plasmon decay in dense plasmas and warm dense matter

The decay of the Langmuir waves in dense plasmas is not accurately predicted by the prevalent Landau damping theory. A dielectric function theory is introduced, predicting much higher damping than the Landau damping theory. This strong damping is in better agreement with the experimentally observed data in metals. It is shown that the strong plasmon decay leads to the existence of a parameter regime where the backward Raman scattering is unstable while the forward Raman scattering is stable. This regime may be used to create intense x-ray pulses, by means of the the backward Raman compression.…

Electronic excitations in atomic clusters: beyond dipole plasmon

Multipole electron modes beyond the Mie plasmon in atomic clusters are investigated within the time-dependent local density approximation theory (TDLDA). We consider the origin of the modes, their connection with basic cluster properties and possible routes of experimental observation. Particular attention is paid to infrared magnetic orbital modes, scissors and twist, and electric quadrupole mode. The scissors and twist modes determine orbital magnetism of clusters while the electric quadrupole mode provides direct access to the single electron spectra of the cluster. We examine two-photon pr…