Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7131226 | Optics and Lasers in Engineering | 2018 | 6 Pages |
Abstract
Recently, we have demonstrated a longitudinally pumped tunable dual-wavelength Ti:sapphire laser that can operate at simultaneous dual-wavelength (765.0, 771.3â¯nm), (763.9, 772.2â¯nm), (763.5, 772.2â¯nm) and (762.4, 773.7â¯nm) with a pulse width of â¼20â¯ns and a maximum average power of â¼2.98â¯W at 1-kHz pulse repetition rate, corresponding to a slope efficiency of â¼34.7% [1]. In this paper, the feasibility of the contactless differential absorption lidar (DIAL) equipped with the dual-wavelength laser emitting at 762â¯nm (on-wavelength) and 773â¯nm (off-wavelength) on remote 3D-measurement of molecular oxygen, O2, has been investigated. Absorption by atmospheric oxygen A-band at 761.9â¯nm corresponds to the magnetic dipole transition b1Σb+(vâ²=0)âX3Σgâ(vâ³=0) with absorption cross section of 5.749â¯Ãâ¯10â3 cmâ2 atmâ1 at STP. The accuracy and dynamic range of the DIAL measurement can be extended by simultaneous transmission and detection the spectrally close “on” and “off” wavelengths generated in a compact single laser, in addition to reduce the cost, volume, and weight of the system. The results demonstrate that a concentration of less than 1â¯ppm by volume is detectable by the system if a path length of 1â¯km is used. It is noticeable that the wavelengths 762â¯nm and 773â¯nm in the near-infrared window spectral range (650-950â¯nm) allow lidar system to monitor dissolved oxygen in ambient water. This system can also be used from a satellite to quickly characterize O2 in H2O matrices in the outer solar system bodies.
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Authors
Gholamreza Shayeganrad,