Abstract
An evanescent-wave quartz-enhanced photoacoustic spectroscopy (EW-QEPAS) CO sensor was developed using a tapered fiber integrated with the quartz tuning fork (QTF) and micro-resonator (mR) tubes. The fiber taper was inserted through the two mR tubes with the taper waist located between the QTF prongs. A fiber-coupled continuous-wave distributed feedback (DFB) laser at 2.3 μm was connected with the fiber taper fabricated by the flame-brushing method. The fiber taper has negligible influence on the resonant frequency and Q-factor of the QTF, but significantly reduces the background noise compared with the recently developed fiber tip-based EW-QEPAS sensor. In the EW-QEPAS detection with wavelength modulation spectroscopy, we investigated the optimal modulation depth and gas pressure, which are different from that of the conventional free-space QEPAS detection. The current CO sensor achieved a minimum detection limit of ∼20 ppm at the 210-s averaging time, corresponding to a normalized noise equivalent absorption (NNEA) coefficient of 1.44 × 10−8 cm−1 W/√Hz.
| Original language | English |
|---|---|
| Pages (from-to) | 1023-1028 |
| Number of pages | 6 |
| Journal | Sensors and Actuators, B: Chemical |
| Volume | 248 |
| DOIs | |
| Publication status | Published - 1 Jan 2017 |
Keywords
- CO detection
- Evanescent-wave absorption
- Fiber taper
- Quartz-enhanced photoacoustic spectroscopy
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Instrumentation
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry