GUIDE-STAR LASER SOURCE

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. RESEARCHERS ARE DEVELOPING A FLASHLAMP-PUMPED DYE-LASER SYSTEM 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 10(10) SHOTS IN SIMILAR APPLICATIONS CAN BE USED TO MAKE PULSED DYE LASERS MUCH MORE COMPACT AND RELIABLE. THESE ADVANCES AND DYE-LASER MODELING CODES WILL BE USED TO DESIGN A GUIDE-STAR LASER SOURCE. A FLASHLAMP-PUMPED DYE LASER HAVING SPECTRAL, SPATIAL, AND TEMPORAL CHARACTERISTICS THAT ARE CONSISTENT WITH THE GUIDE-STAR APPLICATION WILL BE DESIGNED.