  We present a method for determining correlations in a gas of indirect
excitons in a semiconductor quantum well structure. The method involves
subjecting the excitons to a periodic electrostatic potential that causes
modulations of the exciton density and photoluminescence (PL). Experimentally
measured amplitudes of energy and intensity modulations of exciton PL serve as
an input to a theoretical estimate of the exciton correlation parameter and
temperature. We also present a proof-of-principle demonstration of the method
for determining the correlation parameter and discuss how its accuracy can be
improved.
