Can lasing at visible wavelengths be achieved using the low-loss long-range surface plasmon-polariton mode?

The use of emissive dye molecules as a gain medium in order to excite the low-loss long-range surface plasmon-polariton (SPP) mode on a thin silver film has previously been suggested as a method of achieving SPP lasing at visible wavelengths. Here, we consider the gain lost to the short-range SPP, an aspect that has not been investigated before and which may preclude the possibility of lasing. We show by experiments that gain will indeed be lost to the short-range mode. From a computational study, we find that despite gain lost to the short-range mode, SPP based lasing may still be possible using the long-range mode, although we identify a number of requirements that might make lasing difficult to achieve in practice.