Search

Manipulating spoof surface plasmon polaritons (SPPs) effectively has promising applications in developing ultracompact plasmonic circuits. Research on versatile components in planar spoof SPP waveguides has attracted widespread attention over the decades. In particular, cascaded chip-scale devices play an important role in enhancive buffering, highly-sensitive sensing and nonlinear interaction. Herein, we propose a novel strategy to manipulate the switching and slow wave features of spoof SPPs on the basis of plasmon-induced transparency (PIT) spectral responses. A combined module consisting of split square-ring resonators and electric-LC resonators is loaded with a spoof SPP waveguide along the propagating trajectory, where the destructive interference between the two resonators contributes to the PIT behavior and the group delay of the spoof SPPs. A modulation contrast of up to 16.2 dB is achieved for the spoof SPP transmission at the PIT peak frequency. The measurements are consistent with both full-wave simulations and theoretical calculations. Cascaded capabilities performed by installing multiple PIT modules at an interval of an equivalent wavelength are accomplished in the planar spoof SPP waveguide. The proposed strategy opens up fascinating prospects on highly integrated plasmonic circuits and networks. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate a passively mode-locked ring fiber laser operating in the stretched-pulse regime. The ring cavity model is constructed with standard single-mode fiber and dispersion delay line for dispersion management. Here, all-solid Yb-doped photonic bandgap fiber is used as the dispersion delay line and provides laser gain simultaneously. As the all-solid Yb-doped photonic bandgap fiber has large third-order dispersion, it is necessary to study its impact on the stretched-pulse operation. The presence of the third-order dispersion reduces pulse quality because of the relatively small group velocity dispersion. To improve the pulse quality, a spectral filter is employed in the model. The simulation results show that spectral filtering could improve the pulse quality and shorten the pulse duration. Meanwhile, the optimum filter bandwidth is studied. [Copyright &y& Elsevier]

Abstract: A passively mode-locked all-fiber ring laser is constructed based on all-solid Yb-doped photonic bandgap fibers (AS-Yb-PBGF), which provides the laser gain and anomalous dispersion simultaneously. Without any other dispersion compensators, the cavity is simple, compact, and maintenance- and alignment-free. The characteristics of wave-breaking-free operation in the laser are investigated by means of numerical simulations using the split-step Fourier method. The approximately parabolic pulses can be generated and evolved for maintaining the normal group-velocity dispersion intracavity, when the length of the single-mode fiber is between 2 and 4m. The obtained highest energy of the output pulse is up to 2.27nJ with the pulse duration of 8.61ps, corresponding to the time-bandwidth product of 10.05. By dechirping out of cavity, the pulse duration is 0.70ps. [Copyright &y& Elsevier]

Hysteretic behavior in ion gel-graphene hybrid terahertz (THz) modulator is presented. The ion gel gated graphene modulator was designed and fabricated by conventional wet-based graphene transfer method. The modulation performance and hysteretic behavior of the device was characterized by THz time-domain spectroscopy. The dependence of hysteresis on the sweeping voltage rate and sweeping range was explored in a continuous wave terahertz system. The temporal response of the sample was also measured and fitted by a double-exponential expression, which indicated that there were two mechanisms that might cause the hysteresis in the THz modulator. This hysteretic behavior is promising in developing nonvolatile memory devices. Image 1 [ABSTRACT FROM AUTHOR]