1. Gas sensing system based on an all-fiber photothermal microcellMatej Njegovec, Jure Javornik, Simon Pevec, Vedran Budinski, Tomaž Gregorec, Benjamin Lang, Manuel Tanzer, Alexander Bergmann, Denis Đonlagić, 2024, izvirni znanstveni članek Opis: This article presents an all-fiber, miniature Fabry-Perot gas sensor based on photothermal absorption spectroscopy with a custom-made and cost-efficient interrogation system. The sensing gas microcell has a diameter of 125 μ m and a length of 1 mm, and allows for free gas exchange within the optical resonator through micromachined slits. High light intensity and confinement are ensured by delivering the excitation light directly into the gas microcell through a lead-in single-mode fiber. This enhances the photothermal effect and provides a short system response time. The interrogation system utilizes the modulation of an excitation laser diode with a fixed frequency while locking the probe laser onto the gas microcell’s quadrature point (QP) and observing the variations of the reflected optical power. To show the potential of the proposed system, nitrogen dioxide (NO2 was measured in dry air. Thereby, a limit of detection of 20 ppm could be achieved for 10 s integration time. Furthermore, the small dimensions of the sensor allow for improved dynamic performance with photothermal modulation frequencies as high as 7 kHz.
Ključne besede: Fabry–Perot interferometer, FPI, fiber gas cell, fiber gas sensor, nitrogen dioxide, NO2, photothermal effect
Objavljeno v DKUM: 29.08.2024; Ogledov: 96; Prenosov: 19
 Celotno besedilo (15,77 MB) |
2. Photothermal gas sensing with a custom-made, fiber-coupled Fabry–Pérot etalonManuel Tanzer, Benjamin Lang, Matej Njegovec, Vedran Budinski, Simon Pevec, Jure Javornik, Denis Đonlagić, Alexander Bergmann, 2024, izvirni znanstveni članek Opis: Growing awareness of the adverse health effects of air pollution has increased the demand for reliable, sensitive, and mass-producible sensor systems. Photothermal interferometry has shown great promise for sensitive, selective, and miniaturized gas sensing solutions. This work describes the development of a macroscopic photothermal sensor system with a sensor head consisting of a low-cost, custom-made, and fiber-coupled Fabry–Pérot etalon. The sensor was tested with NO2, achieving a 3σ limit of detection (LOD) of approximately 370 ppbv (1 s). Exhibiting little drift, a LOD of 15 ppbv is achievable for 200 s integration time. Compensating for the excitation power, the normalized noise equivalent absorption was calculated to be 1.4 × 10−8cm−1 W√Hz. The sensor system is not limited to NO2 but can be used for any gas or aerosol species by exchanging the excitation laser source.
Ključne besede: photothermal gas, etalon, interferometry, Fabry-Perot
Objavljeno v DKUM: 29.08.2024; Ogledov: 77; Prenosov: 83
Celotno besedilo (2,37 MB)
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