  A new scheme of hard x-ray or gamma ray light is considered. The excitation
of the Langmuir wave in an ultra dense electron beamm via the two-stream
instabilities and the interaction of the excited Langmuir wave with the visible
light-laser results in hard x-ray or gamma ray via three-wave interaction. The
analysis suggests that the hard x-ray with the wave-lenght as small as 0.03 nm
can be achieved. The plausible parameter for the practical use is proposed and
the comparison with the conventional methods are provided.
