Demonstration of a Circularly Polarized Plasma-Based Soft-X-Ray Laser

We report the first experimental demonstration of a laser-driven circularly polarized soft-x-ray laser chain. It has been achieved by seeding a 32.8 nm Kr IX plasma amplifier with a high-order harmonic beam, which has been circularly polarized using a four-reflector polarizer. Our measurements testify that the amplified radiation maintains the initial polarization of the seed pulse in good agreement with our Maxwell-Bloch modeling. The resulting fully circular soft-x-ray laser beam exhibits a Gaussian profile and yields about 10(10) photons per shot, fulfilling the requirements for laboratory-scale photon-demanding application experiments110121sciescopu

Table-top femtosecond soft X-ray laser by collisional ionization gating

The advent of X-ray free-electron lasers has granted researchers an unprecedented access to the ultrafast dynamics of matter on the nanometre scale(1-3). Aside from being compact, seeded plasma-based soft X-ray lasers (SXRLs) turn out to be enticing as photon-rich(4) sources (up to 10(15) per pulse) that display high-quality optical properties(5,6). Hitherto, the duration of these sources was limited to the picosecond range(7), which consequently restricts the field of applications. This bottleneck was overcome by gating the gain through ultrafast collisional ionization in a high-density plasma generated by an ultraintense infrared pulse (a few 10(18) W cm(-2)) guided in an optically pre-formed plasma waveguide. For electron densities that ranged from 3 x 10(18) cm(-3) to 1.2 x 10(20) cm(-3), the gain duration was measured to drop from 7 ps to an unprecedented value of about 450 fs, which paves the way to compact and ultrafast SXRL beams with performances previously only accessible in large-scale facilities17131sciescopu

Table-top femtosecond soft X-ray laser by collisional ionization gating

International audienceThe advent of X-ray free-electron lasers has granted researchers an unprecedented access to theultrafast dynamics of matter on the nanometre scale(1-3). Aside from being compact, seededplasma-based soft X-ray lasers (SXRLs) turn out to be enticing as photon-rich(4) sources (up to 10(15)per pulse) that display high-quality optical properties(5,6). Hitherto, the duration of these sources waslimited to the picosecond range(7), which consequently restricts the field of applications. This bottleneckwas overcome by gating the gain through ultrafast collisional ionization in a high-density plasmagenerated by an ultraintense infrared pulse (a few 10(18) W cm(-2)) guided in an optically pre-formedplasma waveguide. For electron densities that ranged from 3 x 10(18) cm(-3) to 1.2 x 10(20) cm(-3), thegain duration was measured to drop from 7 ps to an unprecedented value of about 450 fs, which pavesthe way to compact and ultrafast SXRL beams with performances previously only accessible inlarge-scale facilities