Fiber interrogated and graphene enhanced Brillouin optomechanical microresonator for ultra-sensitive gas detection

Forward phase-matched Brillouin optomechanical resonance, excited by a tapered fiber, in a graphene inner-deposited whispering-gallery-mode microfluidic cavity, is demonstrated for the first time. The generated Brillouin optomechanical modes with Q factor ∼ 47000 show extremely high sensitivity (200kHz/ppm) for absolute gas detection based on frequency variation, achieving a detection limit down to 1 ppb and a dynamic range >10
⁵
orders of magnitude.