  We propose a method for remotely detecting backward reflection via induced
decay of cold dark matter such as axion in the background of a propagating
coherent photon field. This method can be particularly useful for probing
concentrated dark matter streams by Earth's gravitational lensing effect.
Formulae for the stimulated reflection process and the expected sensitivities
in local and remote experimental approaches are provided for testing eV scale
axion models using broad band lasers. The generic axion-photon coupling is
expected to be explorable up to ${\cal O}(10^{-12})$ GeV${}^{-1}$ and ${\cal
O}(10^{-22})$ GeV${}^{-1}$ for the idealized local and remote setups,
respectively.
