Optical gain and switching

One of the earliest motivations for development of quantum dots was for optical gain media. Using a state-resolved pumping scheme, we have demonstrated for the first time that optical gain is dependent upon the initial excitonic state. By prescribing the specific multiexcitonic states which can create, block, and ultimately control optical gain spectra, we have recovered the theoretically predicted size independence, even in systems which previously showed zero gain. Building on our previous results, we have recently gone one step further and provided for the first time the proof of concept that quantum dots can be used as a platform to perform all-optical logic.