  In contrast to recent studies [Rabl, Phys. Rev. Lett. 107, 063601 (2011);
Nunnenkamp et al., Phys. Rev. Lett. 107, 063602 (2011)] on photon blockade that
prevents subsequent photons from resonantly entering the cavity in
optomechanical systems, we study the photon-induced tunneling that increases
the probability of admitting subsequent photons in those systems. In
particular, we analytically and numerically show how twoor three-photon
tunneling can occur by avoiding single-photon blockade. Our study provides
another way on photon control using a single mechanical resonator in
optomechanical systems.
