  Existence and growth of amorphous order in supercooled liquids approaching
glass transition is a subject of intense research. Even after decades of work,
there is still no clear consensus on the molecular mechanisms that lead to a
rapid slowing down of liquid dynamics approaching this putative transition. The
existence of a correlation length associated with amorphous order has recently
been postulated and also been estimated using multi-point correlation functions
which cannot be calculated easily in experiments. Thus the study of growing
amorphous order remains mostly restricted to systems like colloidal glasses and
simulations of model glass-forming liquids. In this Letter, we propose an
experimentally realizable yet simple correlation function to study the growth
of amorphous order. We then demonstrate the validity of this approach for a few
well-studied model supercooled liquids and obtain results which are consistent
with other conventional methods.
