The effects of local density of states to Purcell factor in Surface plasmon polaritons

Surface plasmon polaritons is a kind of electromagnetic oscillation coupled with the undulation of charge intensity, which is excited at the interface between metal and dielectric. With the properties of near-field enhancement and short wavelength, surface plasmon polaritons play an important role in nano photonics. We use an unambiguous definition to represent the local density of electromagnetic states(LDOS) near the interface of metallic surfaces, which has relationship with Purcell factor. We then calculate LDOS and Purcell factor at different heights above a semi-infinite sample of various metallic materials and have the conclusion that Ag is more suitable for designing Single photon sources.