  The elastic properties of the double-stranded DNA handles used in optical
tweezers experiments on biomolecules are customarily modeled by an extensible
worm-like chain model. Fitting such model to experimental data however is no
trivial task, as the function depends on four parameters in a highly non-linear
fashion. We hereby propose a method to bypass the fitting procedure and obtain
an empirical force vs. extension curve that accurately reproduce the elasticity
of the handles.
