  We establish an explicit analogy between the dynamical Casimir effect and the
photon emission of a thin non-linear crystal pumped inside a cavity. This
allows us to propose a system based on a type-I optical parametric oscillator
(OPO) to simulate a cavity oscillating in vacuum at optical frequencies. The
resulting photon flux is expected to be more easily detectable than with a
mechanical excitation of the mirrors. We conclude by comparing different
theoretical predictions and suggest that our experimental proposal could help
discriminate between them.
