Generation of efficient ultrafast laser-plasma x-ray sources

When a subpicosecond laser is focused onto the surface of a solid, a high-density, short-lived plasma is created. Experimental observations demonstrate that subpicosecond laser-produced plasmas can generate subpicosecond x-ray pulses under the right conditions. The plasma x-ray emission extends over a broad spectral bandwidth and arises mainly from continuum emissions in the high-density plasma. Such a plasma source can be very efficient because almost 90% of the excitation laser energy can be coupled into the solid target and used to heat the target electrons to high temperature.