  We demonstrate in a general framework that polarized photons by backscattered
laser beams of adjustable frequencies at a TeV linear $e^+e^-$ collider provide
us with a very efficient mechanism to probe CP violation in two-photon
collisions. CP violation in the process $\gamma\gamma\rightarrow W^+W^-$ is
investigated in detail with linearly polarized photon beams. There are two
useful CP-odd asymmetries that do not require detailed information on $W$ decay
products. The sensitivity to the CP-odd form factors are studied quantitatively
by assuming a perfect $e$-$\gamma$ conversion and the 20 fb$^{-1}$ $e^+e^-$
integrated luminosity at the $e^+e^-$ c.m. energies $\sqrt{s}=0.5$ and $1.0$
TeV. The sensitivity is so high that such experiments will allow us to probe
new CP violation effects beyond the limits from some specific models with
reasonable physics assumptions. We find that a counting experiment of $W^+W^-$
events in the two-photon mode with adjustable laser frequencies can have much
stronger sensitivity to the CP-odd $\gamma(\gamma) WW$ form factors than can a
$W^+W^-$ decay-correlation experiment with a perfect detector achieve in the
$e^+e^-$ mode.
  PACS number(s): 14.70.Bh, 14.70.Hp, 13.88.+e
