title: Hollow-core fiber Fabry-Perot photothermal gas sensor.
abstract: A highly sensitive, compact, and low-cost trace gas sensor based on photothermal effect in a hollow-core fiber Fabry-Perot interferometer (FPI) is described. The Fabry-Perot sensor is fabricated by splicing a piece of hollow-core photonic bandgap fiber (HC-PBF) to single-mode fiber pigtails at both ends. The absorption of a pump beam in the hollow core results in phase modulation of probe beam, which is detected by the FPI. Experiments with a 2 cm long HC-PBF with femtosecond laser drilled side-holes demonstrated a response time of less than 19 s and noise equivalent concentration (NEC) of 440 parts-per-billion (ppb) using a 1 s lock-in time constant, and the NEC goes down to 117 ppb (2.7×10-7in absorbance) by using 77 s averaging time.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Yanzhen
authors.initials: Y
authors.lastname: Tan
authors.forename: Wei
authors.initials: W
authors.lastname: Jin
authors.forename: Yuechuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Yun
authors.initials: Y
authors.lastname: Qi
authors.forename: Hoi Lut
authors.initials: HL
authors.lastname: Ho