Highly sensitive spectroscopy based on a surface plasmon polariton quantum generator
A novel method is proposed for highly sensitive surface spectroscopy based on hole burning in the surface plasmon polariton (SPP) quantum generator spectrum due to absorption by analyzed molecules or clusters located inside the SPP cavity. The SPP quantum generator spectrum is calculated with an account of inhomogeneous broadening due to variations of the active medium transition frequency. The influence of an analyzed sample on the generation spectrum is demonstrated. The realization of the SPP generator spectroscopy based on a 2D cavity is proposed. It is shown that a SPP quantum generator with a sufficiently large cavity is qualitatively different from the usual laser. In particular, the SPP generation mode is not identical to the passive cavity mode and it appears only due to the active medium. Thus, such kinds of SPP generation cannot be described by the usual single-mode approach and one needs to solve the corresponding spatial problem. The sensitivity of the proposed plasmonic generator intracavity spectroscopy method is calculated.