  Coherence-enhanced light harvesting has not been directly observed
experimentally, despite theoretical evidence that coherence can significantly
enhance light-harvesting performance. The main experimental obstacle has been
the difficulty in isolating the effect of coherence in the presence of
confounding variables. Recent proposals for externally controlling coherence by
manipulating the light's degree of polarization showed that coherent efficiency
enhancements would be possible, but were restricted to light-harvesting systems
weakly coupled to their environment. Here, we show that increases in
system-bath coupling strength can amplify coherent efficiency enhancements,
rather than suppress them. This result dramatically broadens the range of
systems that could be used to conclusively demonstrate coherence-enhanced light
harvesting or to engineer coherent effects into artificial light-harvesting
devices.
