Photon energy up-conversion in semiconductor quantum dots: implications for anti-Stokes cooling

Recent research interest in the field of up-conversion processes has been sparked by the development of multi-colour displays, dynamical imaging microscopy, bio-imaging systems, unconventional lasers and solid-state optical refrigeration devices. In this talk our recent results will be discussed with main focus on one particular up-conversion process, phonon-assisted anti-Stokes emission, in one particular type of semiconductor nanostructure, namely in nanocrystal quantum dots fabricated via colloidal chemistry. These quantum dots represent the ultimate in semiconductor-based quantum-confined system with atom-like energy levels, large optical transition dipole moment and high photoluminescence quantum efficiency. The interest developed in nanocrystal quantum dots has been fuelled by the high degree of reproducibility and control that is currently available in the fabrication and manipulation of these quantum-confined structures.

The feasibility of laser cooling of semiconductor nanocrystal quantum dots by phonon assisted anti-Stokes photoluminescence will be discussed taking into account recent experimental advances.

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