Reconstruction of the wave functions of coupled nanoscopic emitters using a coherent optical technique

We show how coherent, spatially resolved spectroscopy can disentangle complex hybrid wave functions into wave functions of the individual emitters. This way, detailed information on the coupling of the individual emitters, not available in far-field spectroscopy, can be revealed. Here we propose a quantum state tomography protocol that relies on the ability to selectively excite each emitter individually by spatially localized pulses. Simulations of coupled semiconductor GaAs/InAs quantum dots using light fields available in current nanoplasmonics show that undesired resonances can be removed from measured spectra. The method can be applied to a broad range of coupled emitters to study the internal coupling, including pigments in photosynthesis and artificial light harvesting.