Quantum devices - a proper niche for plasmonics
For the last two decades plasmonic devices have been in the focus of attention of scientific community, promising to revolutionize the opto-electronic technology by developing high performance sub-wavelength devices and circuits. These promises have not come to fruition, primarily due to strong losses experienced by the optical and infrared waves in the metals. To this day plasmonics has been successful in a very limited range of practical applications, primarily those where the high absolute efficiency may not be required, such as sensing. These current state of the progress (or lack of such) in plasmonics should not, however, discourage the researchers from looking for relatively narrow niches where the inherently high loss in plasmonic devices may not be an obstacle. One such niche, in our view, is the development of single photon emitters. When one considers the enhancement of external radiation rate provided by the sub-wavelength plasmonic cavity one discovers that despite high loss and quenching, the enhancement can easily surpass that offered by all-dielectric photonic cavities with much lower loss. In this talk we show how one can optimize the emission rate and how this optimization is different from the optimization of the efficiency of radiation. Various plasmonic and photonic structures will be considered in combination with different quantum emitters, both optically and electrically pumped. The unequivocal conclusion is that quantum optics may be precisely the place where plasmonics can shine.