  A scalar field dark energy candidate could couple to ordinary matter and
photons, enabling its detection in laboratory experiments. Here we study the
quantum properties of the chameleon field, one such dark energy candidate, in
an "afterglow" experiment designed to produce, trap, and detect chameleon
particles. In particular, we investigate the possible fragmentation of a beam
of chameleon particles into multiple particle states due to the highly
non-linear interaction terms in the chameleon Lagrangian. Fragmentation could
weaken the constraints of an afterglow experiment by reducing the energy of the
regenerated photons, but this energy reduction also provides a unique signature
which could be detected by a properly-designed experiment. We show that
constraints from the CHASE experiment are essentially unaffected by
fragmentation for $\phi^4$ and $1/\phi$ potentials, but are weakened for
steeper potentials, and we discuss possible future afterglow experiments.
