Pulsed laser and particle beams offer prospects of generating intense Planck radiation in mm-size cavities of high-Z material. In order to achieve isotropy and high temperature, confinement of the radiation through multiplereemission by the wall of the cavity is necessary. This requires heating of the wall material to a certain depth,necessitating energetic pulses from the source. In experiments performed at the Max-Planck-Institut für Quantenoptik (MPQ) at Garching and at the Institute of Laser Engineering (ILE) at Osaka with laser light of 1.3, 0.53and 0.44 μm wavelength, brightness temperatures up to 2.2 × 106 K have been achieved in gold cavities with one- to two- fold reemission of the x-rays. A more favourable laser-plasma interaction and x-ray conversion efficiencymay be obtained by shorter wavelength lasers.
Enhanced multi-keV x-ray emission with a low-coherence laser