Seeding of a soft-x-ray laser in a plasma waveguide by high harmonic generation

Abstract

A strongly saturated waveguide-based optical-field-ionization soft-x-ray laser seeded by high harmonic generation was demonstrated for Ni-like Kr lasing at 32.8 nm. Compared with the same laser seeded only with spontaneous emission, seeding with high harmonics yields much smaller divergence, enhanced spatial coherence, and controlled polarization. The integration of high harmonic seeding, optically preformed plasma waveguide, and optical-field-ionization pumping forms one of the optimal archetypes of an ultrashort-pulse soft-x-ray laser.

Proposal for precision wavelength measurement of the Ni-like gadolinium x-ray laser formed during the interaction of a nanostructured target with an ultrashort laser beam

“…Recent years have seen the development of a new line of XRL research, which involves the optical field ionization (OFI) of krypton (Kr IX, λ = 32.8 nm) [16,17] and xenon (Xe IX, λ = 41.8 nm) [18] cluster jets. The cluster jets were formed in a slit supersonic nozzle.…”

Atomically thin spherical shell-shaped superscatterers based on a Bohr model

“…Analytical Mie scattering theory is applied to solve this scattering problem [51,52]. Different from the 2D case where TM and TE waves are defined according to the axis of the cylinder [33], the electromagnetic fields in 3D case can be decomposed into TM and TE waves with respect to the radial directionr, namely H TM = ∇×(Φ TM r) and E TE = ∇ × (Φ TE r), where Φ TM is the electric potential and Φ TE is the magnetic potential. For the incident field, its corresponding electric potential Φ TM and magnetic potential Φ TE are…”

“…In order to loose the requirement, Ruan and Fan [23,24] proposed a kind of subwavelength superscatterer by engineering an overlap of resonances of different plasmonic modes where they only use multilayered isotropic plasmonic structures. To extend their superscatterer into the deep-subwavelength scale, we put forward the idea of using graphene monolayer to realize cylindrical superscatterers with the advantage of active tunability [33]. Since graphene is a two dimensional carbon sheet with only one atom thick [34,35], this superscatterer can be treated as one kind of "surface superscatterers".…”

Optically self-photopumped x-ray laser at 13.4 nm in Ni-like tin (Sn22+)

“…In recent years, a new direction for XRLs was developed. It involves the optical field ionization (OFI) of krypton (Kr IX, λ = 32.8 nm) [6,7] and xenon (Xe IX, λ = 41.8 nm) [8] cluster jets. A compact 32.8 nm XRL with a quantum yield of 10 12 photons per pulse, which is suited to many applications, has been developed [9].…”

“…Experiments [6][7][8][9] have shown the fundamental advantages of using solid nanostructured/cluster targets for creating highly efficient XRLs. The principal prerequisites were discussed in [11]: (i) absorption of more than 90% of the pump energy is possible; (ii) weak reflection of the pump beam from the nanostructured cluster target and the absence of debris from the plasma; (iii) attainment of electron energies of several keV; (iv) energy deposition into the cluster plasma, as well as ion and electron temperatures being controlled by the cluster size and pump pulse contrast; (v) Plasma density being controlled by the cluster density and size; (vi) ionization balance being controlled by the pump laser intensity I pump ; (vii) high purity and the absence of oxides; and (viii) an undoubted advantage of solid nanostructured targets for achieving a high degree of coherence of the output XRL beam.…”