Accurate removal of RAM from FM laser beams

摘要

We demonstrate here a RAM cancellation method of reaching locking accuracy at shot-noise sensitivity level, and with a reserve precision sufficient to still be free of RAM-induced problems when the bandwidth has been narrowed to some tens of milliHz. Non-optical rf pickup sets the current limit at 2.8 ppm. Basically this paper announces the RAM-Buster approach needed to achieve the ideal spectroscopic accuracy, shotnoise-limited, as had been anticipated in the 1983 Drever et al. paper.