No abstract

Hydrogen is widely used in industrial production, clinical medicine, and as fuel. Hydrogen becomes explosive when the hydrogen-air mixture ranges from 4 to 76 vol%; thus, a rapid hydrogen concentration...

Nanomechanical sensors made from suspended graphene are sensitive to pressure changes. However, these devices typically function by obtaining an electrical signal based on the static displacement of a suspended graphene membrane and so, in practice, have limited sensitivity and operational range. The present work demonstrates an optomechanical Au/graphene membrane-based gas pressure sensor with ultrahigh sensitivity. This sensor comprises a suspended Au/graphene membrane appended to a section of hollow-core fiber to form a sealed Fabry–Pérot cavity. In contrast to conventional nanomechanical pressure sensors, pressure changes are monitored via resonant sensing with an optical readout. A miniature pressure sensor based on this principle was able to detect an ultrasmall pressure difference of 1 × 10–7 mbar in the ultrahigh-vacuum region with a pressure range of 4.1 × 10–5 to 8.3 × 10–6 mbar. Furthermore, this pressure sensor can work over an extended pressure range of 7 × 10–6 mbar to 1000 mbar at room temperature, outperforming commercial pressure sensors. Similar results were obtained using both the fundamental and higher-order resonant frequencies but with the latter providing improved sensitivity. This sensor has a wide range of potential applications, including indoor navigation, altitude monitoring, and motion detection.

A gas pressure sensor, based on a phase-shifted fiber Bragg grating (PS-FBG) modulated by a hollow cavity, is proposed and demonstrated in this Letter. The device was fabricated by fusing a hollow-core fiber (HCF) between two single-mode fibers (SMFs) exhibiting FBGs that were inscribed using line-by-line femtosecond (fs) laser etching. A pair of micro-channels were drilled orthogonally into the HCF using an fs laser to allow the argon gas to get in and out freely. Such a sensor exposes a high spectrum finesse, e.g., a Q -factor of ∼ 7302 , which can be improved by increasing the grating pitch quantity. Furthermore, a high gas pressure sensitivity of 1.22 nm/Mpa is obtained, corresponding the improved sensor with a grating pitch quantity of 300 and a hollow cavity length of 88.3 µm. In addition, the device exhibited a low temperature sensitivity of 8.92 pm/°C.