  We suggest a new application for the long-baseline and high powered cavities
in a laser-interferometric gravitational-wave~(GW) detector to search for WISPs
(weakly interacting sub-eV particles), such as a hidden U(1) gauge boson,
called the hidden-sector photon. It is based on the principle of a light
shining through the wall experiment, adapted to the laser with a wavelength of
1064 or 532 nm. The transition edge sensor (TES) bolometer is assumed as a
detector, which the dark rate and efficiency are assumed as
$0.000001~\mathrm{s^{-1}}$ and 0.75, respectively. The TES bolometer is
sufficiently sensitive to search for the low-mass hidden-sector photons. We
assume that the reconversion cavity is mounted on the reconversion region of
hidden-sector photons, which number of reflection and length are assumed as
1000 and 10, 100, and 1000m. We found that the second-point-five and the second
generation GW experiments, such as KAGRA and Advanced LIGO with a regeneration
cavity and TES bolometers. The expected lower bounds with these experiments wit
the reconverted mirror are set on the coupling constant $\chi = 2 \times
10^{-9}$ for hidden-sector photon with a mass of $2 \times 10^{-5}$ eV within
95% confidence level. The third generation detector, Einstein Telescope, will
reach $\chi = 1 \times 10^{-9}$ at a mass of $1 \times 10^{-5}$ eV within 95%
confidence level. Although the operation and construction of the RC will demand
dedicated optical configurations, the cavities used in GW detection are
expected to measure the strong potential for finding the hidden-sector photons.
