  Left-handedness with three zero-absorption windows is achieved in a
triple-quantum dot (TQD) system. With the typical parameters of a GaAs/AlGaAs
heterostructure, the simultaneous negative relative electric permittivity and
magnetic permeability are obtained by the adjustable incoherent pumping field
and two inter-dot tunnelings. What's more, three zero-absorption windows in the
left-handedness frequency bands are observed in the TQD system. The
left-handedness with zero-absorption in solid state heterostructure may solve
not only the challenge in the photonic resonant scheme for left-handed
materials (LHMs) but also the application limitation of the negative refractive
materials with large amount of absorption.
