PolySense

New Publication on Sensors and Actuators B Chemical Journal

The PolySense and Polysense Innovations teams have just published a new article on Sensors and Actuators B Chemical Journal (IF 7.7) reporting on a dual-spectral (QEPAS-LITES) multi-gas detection system based on a single customized quartz tuning fork (QTF). By applying second-harmonic (2 f) wavelength modulation at 1368.6 nm and 1653.7 nm, the fundamental and first-overtone resonance modes of the QTF are excited concurrently, enabling intrinsic frequency-domain separation and parallel demodulation of photoacoustic and photothermal signals.
This streamlined architecture enables truly simultaneous monitoring of percent-level H2O and ppm-level CH4, effectively overcoming the dynamic-range limitations of standard multi-gas sensing. Excellent linearity is obtained for both species (R² = 0.9999 for H₂O and 0.998 for CH₄), with minimum detection limits of approximately 30 ppm and 660 ppb, respectively. Allan-Werle deviation analysis confirms stable long-term operation for both detection channels. By overcoming the dynamic-range and saturation limitations of conventional multi-gas sensors, the proposed dual-mode approach provides a robust and scalable platform for wide-dynamic-range gas sensing in applications including atmospheric greenhouse gas monitoring, industrial emission analysis, and complex open-path environments.

The following link provides access to the article: http://polysense.poliba.it/wp-content/uploads/2026/04/1-s2.0-S0925400526005794-main.pdf

New Publication on International Journal of Hydrogen Energy

The PolySense and Polysense Innovations teams have just published a new article on the International Journal of Hydrogen Energy (IF 8.3) regarding the use of Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) for the detection of CO impurities in hydrogen . Due to the high speed of sound in hydrogen, the geometry of the spectrophone was specifically selected to ensure efficient sound wave amplification. Therefore, a QEPAS spectrophone was designed by exploiting a custom quartz tuning fork operating at first overtone mode (~44,0 kHz) in combination with compact resonator tubes. The spectrophone was integrated into a QEPAS sensor for CO trace detection at 2193.36 cm􀀀 1 in a hydrogen matrix. The QEPAS sensor was calibrated using certified mixtures, returning a detection limit of 1.5 ppm for 10 s.

The following link provides access to the article: http://polysense.poliba.it/wp-content/uploads/2026/04/1-s2.0-S036031992601774X-main.pdf

New Publication on Sensors and Actuators B Chemical Journal

The PolySense and Polysense Innovations teams have just published a new article on Sensors and Actuators B Chemical Journal Elsevier (IF 7.7) reporting on an investigation of the relaxation dynamics of the ν3 energy level of nitrous oxide (N2O) molecules in synthetic air using a 4.5 μm distributed feedback quantum cascade laser (DFB-QCL) combined with photoacoustic spectroscopy (PAS) technique. A comprehensive theoretical model coupling vibration-translation (V-T) relaxation processes and vibration-vibration (V-V) energy transfer was developed, enabling a rigorous theoretical derivation of the system-wide vibrational relaxation time. Through in-depth analysis of photoacoustic signal phase characteristics, the molecular relaxation times of both N2O (ν3) (1.6 μs atm) and H2O (0.33 μs atm) were simultaneously extracted. This research not only validates the technical feasibility and analytical superiority of PAS phase technology in measuring gas relaxation times but also introduces a novel high-precision spectroscopic analysis method for studying vibrational dynamics in complex molecular systems, showcasing its potential applications in environmental monitoring and molecular dynamics research.

The following link provides access to the article:
http://polysense.poliba.it/wp-content/uploads/2025/11/Investigation-of-the-role-of-photoacoustic-phase-in-N2Ov3-vibrational-relaxation-rate-determination_sens-act_B_2025.pdf