Polydimethylsiloxane self-assembled whispering gallery mode microbottle resonator for ethanol sensing.

Ethanol gas has been widely used in biomedicine, transportation, and chemical industry. However, when ethanol gas reaches a certain concentration in a closed space, it is possible to cause explosion. Based on this, a self-assembled whispering gallery mode (WGM) microbottle resonator for ethanol gas sensing is proposed and demonstrated in theory and experiment. The microbottle can be simply fabricated by dipping and pulling a single-mode fiber repeatedly in polydimethylsiloxane (PDMS) by a dip coater. The refractive index and volume of the PDMS will change with the concentration variation of the ethanol gas, resulting in a shift of the resonance wavelength. Experimental results demonstrate that the maximum sensitivity of the sensor to ethanol gas is 36.24 pm/ppm with good stability. Besides, the proposed sensor can behave simple preparation process, low cost, and compact size. • The microbottle can be simply fabricated by dipping and pulling an SMF repeatedly in PDMS. • The microbottle can serve as sensitive film to ethanol gas. • The central radius of the microbottle can be controlled by adjusting the fabrication process. • The ethanol gas sensor based on WGM resonator avoids the fall-off problem of the sensitive material. [ABSTRACT FROM AUTHOR]