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Gas-phase pressure measurements remain challenging in situations where local pressure rapidly changes or in hostile environments such as turbulent combustion. In this work, we demonstrate the implementation of the recently developed femtosecond laser-induced grating scattering (fs-LIGS) technique for pressure measurement in ambient air. With an overall femtosecond laser pulse energy of 185 μJ, fs-LIGS signals were generated for various gas pressure ranging from 0.2 to 3.0 bar. By theoretically fitting the signal and extracting the time constant of the stationary density modulation damping, the pressure is successfully derived. The derived values were compared to the gauge pressure, which shows a quasi-linear dependence with a slope of 0.96, suggesting the feasibility of the fs-LIGS technique for gas-phase pressure measurements.

The N 2 + lasing spectra with varying time delays are measured with two different polarizations of pump pulse. The inhibited time-dependent oscillation indicates that the polarization-modulated pump pulse can reduce the coherence between different rotational states.

We experimentally demonstrated a real-time wind speed monitoring methord by utilizing fiber-optic sensors to acquire and display the value on the computer. © 2020 The Author(s)

An OPGW ice-coating monitoring scheme based on BOTDR temperature measurement is proposed and demonstrated. The scheme is applied to actual transmission line. The temperature measurement accuracy is about ± 1°C. © 2020 The Author(s)