@article{181286,
  keywords = {Photothermal gas sensor, Intracavity gas detection, Solid-state laser, Heterodyne gas detection},
  author = {Grzegorz Dudzik and Karol Krzempek and Krzysztof Abramski and Gerard Wysocki},
  title = {Solid-state laser intra-cavity photothermal gas sensor},
  abstract = {<p>Compact, rugged and sensitive laser-based trace gas sensors are in high demand for science and commercial applications. To ensure high sensitivities, laser spectroscopic sensors often use extended interaction paths (e.g. multi-pass cells), which significantly increases their size, weight and susceptibility to misalignment. Herein, we present a novel, miniaturized photothermal gas sensor, where the gas sample is measured inside the resonator of a monolithic microchip solid-state laser operating at 1064 nm. The photothermal-induced gas refractive index variations are directly translated to a solid-state laser frequency shift, which is detected as a beatnote modulation in a heterodyne detection scheme. The system provides high sensitivity to refractive index changes at the level of \~{}1.1 {\texttimes} 10-12 within ultra-short intra-cavity interaction path-length of 1.5 mm, which enables trace-gas measurements in a sensing volume of only 4 μl. In a proof-of-concept experiment using dry carbon dioxide as a test sample the sensor reached a minimum detection limit of 350 ppbv for a 100 s averaging time and NNEA = 4.1 {\texttimes} 10-8 [W cm-1 Hz-1/2].</p>
},
  year = {2021},
  journal = {Sensors and Actuators B: Chemical},
  volume = {328},
  pages = {129072},
  month = {02/2021},
  isbn = {0925-4005},
  url = {https://doi.org/10.1016/j.snb.2020.129072},
  language = {eng},
}