  We propose a phase-sensitive detection scheme to identify the unconventional
$p_{x}\pm ip_{y}$ symmetry of the condensate wavefunctions of bosons, which
have already been proposed and realized in high bands in optical lattices.
Using the impulsive Raman operation combining with time-of-flight imaging, the
off-diagonal correlation functions in momentum space give rise to the relative
phase information between different components of condensate wavefunctions.
This scheme is robust against the interaction and interband effects, and
provides smoking gun evidence for unconventional Bose-Einstein condensations
with nontrivial condensation symmetries.
