Quantum theory of surface polariton Cherenkov light radiation source and its fluctuation

Abstract

If the speed of the electron beam excited Surface Plasmon Polaritons (SPPs) exceeds the velocity of light in medium, Cherenkov radiation will be emitted. Here, on this important physical phenomenon, Surface Polariton Cherenkov Light Radiation Source (SPCLS), the quantum theory has been worked out. By this theory, the average field amplitude in SPCLS is obtained. The calculation results show that the quantum theory can explain the classical phenomena precisely and predict nonclassical excitation channels of photons that are based on the quantum nature of the electromagnetic field and the effect of SPPs. These excitation channels can be used to shorten the response time of Cherenkov detectors. The quantum theory also shows that SPCLS has a different fluctuation pattern compared with the ordinary electromagnetic systems where vacuum fluctuation dominates. The fluctuation pattern has two significant characteristics: first, the fluctuation of SPCLS will not vanish in the macroscopic case, which may draw theoretical and experimental interest; second, the fluctuation of SPCLS can be tuned by the velocity of the electron beam. Thus, the fluctuation of SPCLS can be used to enhance the radiation through stochastic resonance. Our investigation shows that important phenomena may be found out with the introduction of quantum theory in macroscopic electromagnetic problems.If the speed of the electron beam excited Surface Plasmon Polaritons (SPPs) exceeds the velocity of light in medium, Cherenkov radiation will be emitted. Here, on this important physical phenomenon, Surface Polariton Cherenkov Light Radiation Source (SPCLS), the quantum theory has been worked out. By this theory, the average field amplitude in SPCLS is obtained. The calculation results show that the quantum theory can explain the classical phenomena precisely and predict nonclassical excitation channels of photons that are based on the quantum nature of the electromagnetic field and the effect of SPPs. These excitation channels can be used to shorten the response time of Cherenkov detectors. The quantum theory also shows that SPCLS has a different fluctuation pattern compared with the ordinary electromagnetic systems where vacuum fluctuation dominates. The fluctuation pattern has two significant characteristics: first, the fluctuation of SPCLS will not vanish in the macroscopic case, which may draw theore...