FIBER LASERS: Fiber lasers enter guide-star arena

摘要

A typical laser guide star--formed by illuminating the upper atmosphere with 589 nm light to cause sodium vapor lines to fluoresce--accompanies an adaptive-optics system to compensate for atmospheric turbulence and improve clarity for ground-based telescopes (see www.laserfocusworld.com/articles/365408). Fiber lasers (which require frequency doubling or some other scheme to reach the 589 nm wavelength) could not achieve the typical 20 W power levels required for this application, until European Southern Observatory (ESO; Garching, Germany) researchers a 589 nm fiber laser guide-star source using two coherently combined Raman fiber amplifiers, as first reported at Laser, World of Photonics 2009 (see www.laserfocusworld.com/articles/367027).