Guide-Star Laser Source

最近解密的军事研究证实了人工导星对天文观测大气补偿的适用性。在已经证明的两种可供选择的导星技术中，更有希望的是在海拔95公里的钠层中激光诱导产生一颗人造恒星。所需的激光功率在很大程度上取决于望远镜的观测波长。它的范围从大约2瓦的红外线（2000纳米）到300瓦的可见光（500纳米）。对于一个大型的可见光望远镜来说，需要一个能量约为1焦耳的脉冲激光束，以几百赫兹的频率重复脉冲，并调谐到589纳米的钠- d线，以产生一个合适的导星。要使这种光源为天文学界所接受，这种激光器必须便宜、紧凑和可靠。为此，将开发一种手电筒泵浦染料激光系统。闪光灯泵浦染料激光器设计的最新进展大大提高了可实现的效率和光束质量，而最近开发的全固态磁压缩脉冲发生器技术已经证明，在类似的应用中，寿命为7 x 1010次，可用于使脉冲染料激光器更加紧凑和可靠。这些进展和最近开发的染料激光建模代码将用于设计导星激光源。＊＊＊

9360186 Flusberg Recently declassified military research has validated the applicability of artificial guide stars to atmospheric compensation for astronomical observations. Of the two alternative guide-star techniques that have been demonstrated, the more promising is the laser-induced generation of an artificial star in the sodium layer located at an altitude of 95 km. The required laser power depends strongly on the observation wavelength of the telescope. It ranges from about 2 watts in the infrared (2000 nm) to 300 watts in the visible (500 nm). For a large, visible-light telescope, a pulsed laser beam with approximately one joule of energy, repetitively pulsed at several hundred hertz and tuned to the 589-nm sodium-D line is needed to generate a suitable guide star. To make this source acceptable to the astronomical community, such a laser should be inexpensive, compact and reliable. A flashlamp-pumped dye-laser system will be developed for this application. Recent advances in flashlamp-pumped dye-laser design have greatly increased the achievable efficiency and beam quality, while recently developed all-solid-state magnetic-compression-pulser technology that has demonstrated a lifetime of 7 x 1010 shots in similar applications can be used to make pulsed dye laser much more compact and reliable. These advances and recently developed dye-laser modeling codes will be used to design a guide- star laser source. ***