Photometric observations of a polychromatic laser guide star.
Photometric observations of a polychromatic laser guide star.
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DOI：
10.1364/josaa.17.002236
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发表时间：
2000-12
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通讯作者：
R. Foy;M. Tallon;I. Tallon-Bosc;É. Thiébaut;J. Vaillant;F. Foy;D. Robert;H. Friedman;F. Biraben;G. Grynberg;J. Gex;A. Mens;A. Migus;J. Weulersse;D. Butler
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文献类型：
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作者：
R. Foy;M. Tallon;I. Tallon-Bosc;É. Thiébaut;J. Vaillant;F. Foy;D. Robert;H. Friedman;F. Biraben;G. Grynberg;J. Gex;A. Mens;A. Migus;J. Weulersse;D. Butler
我们报告了劳伦斯利弗莫尔国家实验室 (LLNL) 使用 AVLIS 激光器对多色激光导星 (PLGS) 进行的光度观测。该过程旨在测量由大气湍流引起的望远镜入射波前的倾斜。它依赖于中间层钠原子4D5/2能级的双光子相干激发。我们使用了589和569 nm的两束激光，最大总平均输出功率约为350 W。为了进行光度校准，通过与PLGS相同的仪器在LLNL 50 cm望远镜的焦点处同时观察了一颗天然恒星。 330 nm 返回光通量的光度测量证实了我们之前的理论研究，即 PLGS 过程应该允许我们在后期在良好的天文地点校正短至约 1 微米波长的倾斜。他们还表明，在中间层双光子相干吸收饱和时，当脉冲重复率在恒定平均功率下降低 3 倍时，反向散射通量增加约 2 倍。我们简要讨论了这种意外行为。
We report the photometric observation of a polychromatic laser guide star (PLGS) using the AVLIS laser at the Lawrence Livermore National Laboratory (LLNL). The process aims at providing a measurement of the tilt of the incoming wave front at a telescope induced by atmospheric turbulence. It relies on the two-photon coherent excitation of the 4D5/2 energy level of sodium atoms in the mesosphere. We used two laser beams at 589 and 569 nm, with a maximum total average output power of approximately 350 W. For the purpose of photometric calibration, a natural star was observed simultaneously through the same instrument as the PLGS at the focus of the LLNL 50-cm telescope. Photometric measurements of the 330-nm return flux confirm our previous theoretical studies that the PLGS process should allow us at a later stage to correct for the tilt at wavelengths as short as approximately 1 microm at good astronomical sites. They show also that, at saturation of two-photon coherent absorption in the mesosphere, the backscattered flux increases by a factor of approximately 2 when the pulse repetition rate decreases by a factor of 3 at constant average power. This unexpected behavior is briefly discussed.