589nm Guidestar FASOR
A sodium guidestar created in the mesosphere at 90-km altitude.FASORtronics specializes in the design and manufacture of laser systems to create “guide stars” for astronomical telescopes incorporating adaptive optics. Its founders have expertise in making the high power, single frequency, solid-state lasers and wavelength converters that form the foundation of the FASOR concept, which utilizes a doubly resonant sum-frequency wavelength converter in which two high power single-frequency infrared laser beams are mixed in a non-linear crystal to produce a single-frequency yellow output beam resonant with high altitude sodium atoms.
Two of the FASORtronics founders developed the FASOR technology for the laser guidestar adaptive optical system at the Air Force Research Lab’s Starfire Optical Range (SOR) between 2001 and 2004. Two generations of FASOR systems built during this period produced the brightest guide stars ever and demonstrated the high efficiency and robustness of the technology, meeting the specifications of most planned laser guidestar adaptive optical systems critical to the coming revolution in ground-based astronomy.
The 50-watt FASOR in operation on the Starfire Optical Range 3.5-m adaptive optical telescope.
Several huge ground-based telescopes are planned for completion in the coming decade. These telescopes will create images sharper than those created by existing or planned space-based telescopes, while also collecting light from distant objects more quickly. They depend, however, on the technology of laser guidestar adaptive optics.
FASORtronics is committed to commercializing the FASOR technology for the development of next-generation laser guidestar adaptive optics. The FASOR technology is protected under a U.S. patent held by the Air Force. Two of the FASORtronics founders are co-inventors on that patent. FASORtronics has the exclusive patent license for the commercialization of the FASOR technology.
The third-generation FASOR design shown in its 600x900x600mm enclosure.The second-generation FASOR design has demonstrated over 50-watts of power and has been in use since 2004 on the SOR telescope. FASORtronics' third-generation design has a footprint of 600x900mm in an industrial-type enclosure with facility-class reliability and ease-of-maintenance features. Powers are available exceeding the 50-watt legacy systems and the all-new design is completely independent of the gravity vector -- the FASOR can be placed anywhere on the telescope. The need to access the optical components in the third-generation FASOR has been completely eliminated through the use of remotely controlled optical alignment and other system optimization features.
The third-generation FASOR design also includes the ability to produce two pumping frequencies; one resonant with the sodium D2a transition, and the other one resonant with the D2b transition for an increase of about 1.5x in photon return efficiency via the well-known optical back-pumping process. Both frequencies are precisely tunable to better than 10MHz of the desired transitions and fully monitored via a Wavelength Controller.
The laser optical modules shown without covers: the 1064nm laser, the SFG, and the 1319nm laser (left-to-right).Ease-of-maintenance features are designed into the third-generation FASOR by implementing a concept whereby the laser optical components are built into independent modules. These optical modules are designed to allow rapid field replacement in the event of malfunction; their replacement with a spare unit can be accomplished within a couple of hours without the use of special tools. All of the critical electronics and controllers are built into each of the laser optical modules. The guidestar laser system power supply cabinet is 600x900x600mm and can be placed up to 100m away from the laser optical modules cabinet. The entire FASOR system is water cooled so that its outer surface remains at the ambient temperature.