11 September 1998 Fiber Raman laser for sodium guide star
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The generation of sodium guide stars through laser excitation imposes very specific requirements on the laser. It has been argued that the most effective sodium guide star laser would operate CW with a mode spacing of less than the 10 MHz Doppler broadening profile of the mesospheric sodium. However, achieving high power in free-space optics with these requirements becomes very difficult because of the limited active gain volume and exceedingly long cavity requirement. The clear solution to these impediments is the development of a fiber raman laser (FRL) to shift the output of a solid state laser to a harmonic of the 589 nm sodium transition. The specific wavelength and bandwidth are selected from the large Raman gain spectrum by application- specific Distributed Bragg Reflectors. The guided-wave nature of the FRL allows for very large interaction volumes, while the long fiber length allows for narrowly-spaced modes which easily fill the sodium D2 continuum. This paper reviews the theory and design of the Fiber Raman Guidestar Laser being developed for Astronomical Adaptive Optical systems.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
James T. Murray, James T. Murray, W. Thomas Roberts, W. Thomas Roberts, William Lucas Austin, William Lucas Austin, Richard C. Powell, Richard C. Powell, Domenico Bonaccini, Domenico Bonaccini, } "Fiber Raman laser for sodium guide star", Proc. SPIE 3353, Adaptive Optical System Technologies, (11 September 1998); doi: 10.1117/12.321725; https://doi.org/10.1117/12.321725

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