Resonance-assisted light–control–light characteristics of SnS 2 on a microfiber knot resonator with fast response

An all-optical light-control-light functionality with the structure of a microfiber knot resonator (MKR) coated with tin disulfide (SnS2) nanosheets is experimentally demonstrated. The evanescent light in the MKR [with a resonance Q of similar to 59,000 and an extinction ratio (ER) of similar to 26 dB] is exploited to enhance light-matter interaction by coating a two-dimensional material SnS2 nanosheet onto it. Thanks to the enhanced light-matter interaction and the strong absorption property of SnS2, the transmitted optical power can be tuned quasi-linearly with an external violet pump light power, where a transmitted optical power variation rate Delta T with respect to the violet light power of similar to 0.22 dB/mW is obtained. In addition, the MKR structure possessing multiple resonances enables a direct experimental demonstration of the relationship between resonance properties (such as Q and ER), and the obtained Delta T variation rate with respect to the violet light power. It verifies experimentally that a higher resonance Q and a larger ER can lead to a higher Delta T variation rate. In terms of the operating speed, this device runs as fast as similar to 3.2 ms. This kind of all-optical light-control-light functional structure may find applications in future all-optical circuitry, handheld fiber sensors, etc. (C) 2018 Chinese Laser Press