  The polarization of a top-quark can be sensitive to new physics beyond the
standard model. We propose a novel method to measure top-quark polarization,
based on the charged lepton energy fraction in top-quark decay, and illustrate
the method with a detailed simulation of top-quark pairs produced in
supersymmetric top squark pair production. We show that the lepton energy ratio
distribution that we define is very sensitive to the top-quark polarization but
insensitive to the precise measurement of the top-quark energy.
