The use of two lasers is suggested to freeze microbunches in an optical klystron harmonic generator, and a third laser beam to be sent onto the microbunches. It is shown that under certain conditions there can be intense generation of coherent soft x rays. The calculation of the power indicates the possibility of one-shot x-ray holography.

• Received 22 November 1983

DOI:https://doi.org/10.1103/PhysRevLett.53.254