Femtosecond pulse with THz repetition frequency based on strong coupling between quantum emitters and a plasmonic resonator

Abstract: Nanoscale pulsed light is highly desirable in nano-integrated optics. In this letter, we obtained femtosecond pulses with THz repetition frequency via the strong coupling between quantum emitters (QEs) and plasmonic resonators. Our structure consists of a V-groove (VG) plasmonic resonator and a nanowire embedded with two-level QEs. The influences of the incident light intensity and QE number density on the transmission response for this hybrid system are investigated through semi-classical theory and simulation. It is found that the transmission response can be modulated to the pulse form. The reason is the strong coupling causes the output power of nanowire to behave as an oscillating form, the oscillating output power in turn causes the field amplitude in the resonator to oscillate over time. A feedback system is formed between the plasmonic resonator and the QEs in nanowire. This provides a new method for generating narrow pulsed lasers with ultrahigh repetition frequency in plasmonic systems using a continous wave input, which has potential applications in generating optical clock signals at the nanoscale.