title: Modulating resonance modes and Q value of a CdS nanowire cavity by single Ag nanoparticles.
abstract: Semiconductor nanowire (NW) cavities with tailorable optical modes have been used to develop nanoscale oscillators and amplifiers in microlasers, sensors, and single photon emitters. The resonance modes of NW could be tuned by different boundary conditions. However, continuously and reversibly adjusting resonance modes and improving Q-factor of the cavity remain a great challenge. We report a method to modulate resonance modes continuously and reversibly and improve Q-factor based on surface plasmon-exciton interaction. By placing single Ag nanoparticle (NP) nearby a CdS NW, we show that the wavelength and relative intensity of the resonance modes in the NW cavity can systematically be tuned by adjusting the relative position of the Ag NP. We further demonstrate that a 56% enhancement of Q-factor and an equivalent π-phase shift of the resonance modes can be achieved when the Ag NP is located near the NW end. This hybrid cavity has potential applications in active plasmonic and photonic nanodevices.
authors: State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics,  Tsinghua University , Beijing 100084, People's Republic of China.
authors: Qing
authors: Q
authors: Zhang
authors: Xin-Yan
authors: XY
authors: Shan
authors: Xiao
authors: X
authors: Feng
authors: Chun-Xiao
authors: CX
authors: Wang
authors: Qu-Quan
authors: QQ
authors: Wang
authors: Jin-Feng
authors: JF
authors: Jia
authors: Qi-Kun
authors: QK
authors: Xue