  The observation of single-photon optomechanical effects is a desired task in
cavity optomechanics. However, the realization of ultrastrong optomechanical
interaction remains a big challenge. Here, we present an all-optical scheme to
simulate ultrastrong optomechanical coupling based on a Fredkin-type
interaction, which consists of two exchange-coupled modes with the coupling
strength depending on the photon number in another controller mode. This
coupling enhancement is assisted by the displacement amplification according to
the physical idea of the Bogoliubov approximation, which is realized by
utilizing a strong driving to pump one of the two exchanging modes. Our
numerical simulations demonstrate that the enhanced optomechanical coupling can
enter the single-photon strong-coupling and even ultrastrong-coupling regimes.
We also show the creation of macroscopic quantum superposed states and the
implementation of a weak-to-strong transition for quantum measurement in this
system. This work will pave the way to quantum simulation of single-photon
optomechanical effects with current experimental platforms.
