All-Optical Tuning of Au Nanocluster Functionalized Microfibre Coil Resonator

Abstract

Abstract An all-optical tunable microfibre coil resonator (MCR) functionalized using Au nanoclusters (AuNCs) was investigated and demonstrated. The MCR was manufactured by winding tapered fibre on a hollow rod of low refractive index polycarbonate (PC) resin to form a fluidic channel, and the AuNCs aqueous solution was injected into the channel to complete the functionalization process. The resonance wavelength and extinction ratio can be tuned using a pump laser with wavelength of 808 nm due to the photo-thermal effect and photon generated carriers from strong absorption of AuNCs at 808 nm, resulting light-matter interaction and providing all-optical tuning properties, including variations of resonance wavelength and extinction ratio. The variation rate of the resonance wavelength and extinction ratio were determined as 69 pm/mW and 0.459 dBm/mW. The response times of the MCR functionalized with the AuNCs are 11.99 s (rising) and 11.41 s (falling). The AuNCs functionalized MCR has several advantages compared to other tunable resonator devices, including easy fabrication, high tuning efficiency, low cost and all-fibre construction.