title: High-Q, ultrathin-walled microbubble resonator for aerostatic pressure sensing.
abstract: Sensors based on whispering gallery resonators have minute footprints and can push achievable sensitivities and resolutions to their limits. Here, we use a microbubble resonator, with a wall thickness of 500 nm and an intrinsic Q-factor of 10(7) in the telecommunications C-band, to investigate aerostatic pressure sensing via stress and strain of the material. The microbubble is made using two counter-propagating CO(2) laser beams focused onto a microcapillary. The measured sensitivity is 19 GHz/bar at 1.55 μm. We show that this can be further improved to 38 GHz/bar when tested at the 780 nm wavelength range. In this case, the resolution for pressure sensing can reach 0.17 mbar with a Q-factor higher than 5 × 10(7).
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Sunny
authors.initials: S
authors.lastname: Saurabh
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Ward
authors.forename: Síle
authors.initials: S
authors.lastname: Nic Chormaic