We present a method for producing a single circularly polarized attosecond pulse by an intense few cycle elliptically polarized laser pulse combined with a terahertz field from numerical solutions of the time-dependent Schrödinger equation for the molecular ion H2(+). It is found that in the presence of a 62.5 THz (λ=4800 nm) field at an intensity of ∼10(14) W/cm2, a single circularly polarized 114 as pulse can be generated by an elliptical polarized laser pulse at a wavelength of 400 nm with an ellipticity of ϵ=0.59. The efficiency of circular polarization attosecond pulse generation is interpreted based on a classical model of single electron recollision with the parent ion.
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http://dx.doi.org/10.1103/PhysRevLett.110.023003 | DOI Listing |
We investigate the ultrafast electron correlation effects during non-sequential double ionization (NSDI) of argon subjected to a combined femtosecond field composed of counter-rotating two-color circularly polarized (TCCP) pulse laser using a 3D classical ensemble model (CEM). Our simulation results reveal that manipulation of the carrier-envelope phase (CEP) of the external driving field modulates the dynamical behavior of the two electrons, resulting in a notable sensitivity of their momentum distribution to the relative phase of two components of the counter-rotating TCCP field. Through inversion analysis, we uncover the capability to direct electrons toward a single direction, thereby facilitating focused ion-electron collisions on the attosecond timescale.
View Article and Find Full Text PDFThis paper proposes a reflective metasurface composed of a single unit structure, yet capable of achieving precise control of two degrees of freedom. By grooving two orthogonal slots on the copper ring, it enables the independent conversion of the two orthogonal components of the incident waves. Consequently, incident linearly-polarized waves can be rotated by an arbitrary angle.
View Article and Find Full Text PDFDigital coding metasurfaces have gained considerable attention for their potential to bridge physical and information sciences. However, existing metasurfaces are often restricted to either phase-only or amplitude-only control and typically operate within a single frequency band or polarization, limiting their functionality in advanced electromagnetic applications. This study proposes a dual-band metasurface with independent amplitude-phase coding for polarization-controlled beam manipulation, addressing these limitations.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics and London Centre for Nanotechnology, King's College London, London, WS2R 2LS, UK.
Controlling scattering and routing of chiral light at the nanoscale is important for optical information processing and imaging, quantum technologies as well as optical manipulation. Here, we introduce a concept of rotating chiral dipoles in order to achieve unidirectional chiral scattering. Implementing this concept by engineering multipole excitations in helicoidal plasmonic nanoparticles, we experimentally demonstrate enantio-sensitive and highly-directional forward scattering of circularly polarised light.
View Article and Find Full Text PDFNanoscale
January 2025
State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China.
Hyperbolic metamaterials (HMMs) have recently attracted significant research attention due to their hyperbolic wavevector iso-frequency contour, which leads to substantial local electric field (EF) enhancements that benefit optical processes, such as the nonlinear generation, quantum science, biomedical sensing, and more. However, three main challenges hinder their practical implementation: the difficulty in exciting their resonant modes using free-space incidence, the weak enhancement of surface EF, and the narrow spectral range of EF enhancements. Herein, we proposed cross-etched HMMs (CeHMMs) as a novel type of HMM, addressing these issues.
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