  The number of photons available by coherent X-ray scattering from a single
biomolecule is considerably less because of the extremely small
elastic-scattering cross-section and low damage threshold. Even with a high
X-ray flux of 3 x 10to 12 photons per 100-nm-diameter spot and an ultrashort
pulse of 10 fs driven by a future X-ray free electron laser (X-ray FEL), it has
been predicted that only a few 100 photons will be available by scattering from
a single lysozyme molecule. In this paper I propose a new method: instead of
directly observing the photons scattered from the sample, we amplify the
scattered waves by superimposing an intense coherent reference pump wave on it
and record the resulting interference pattern using a planar X-ray detector,
similar to technique followed in holography. Using a nanosized gold particle as
a reference pump wave source, we can collect 10 to 4 ~ 10 to 5 photons in
single shot imaging where the signal from a single biomolecule is amplified and
recorded as 2D diffraction intensity data. To recover the phase information and
reconstruct the image, the iterative phase retrieval technique will be
applicable. However, the technical difficulty is how to precisely reconstruct
faint image of the single bio-molecular in Angstrom resolution, whose intensity
is much lower than the bright gold particle linked to it. In order to solve
this problem, I propose a new scheme that combines the iterative
phase-retrieval on reference pump wave and digital Fourier transform
holography.
