TY - JOUR KW - frequency drift KW - optical cavity KW - optical lattice clock KW - ultrastable lasers AU - John Robinson AU - Eric Oelker AU - William Milner AU - Wei Zhang AU - Thomas Legero AU - Dan-Gheorghita Matei AU - Fritz Riehle AU - Uwe Sterr AU - Jun Ye AB - Crystalline optical cavities are the foundation of today\textquoterights state-of-the-art ultrastable lasers. Building on our previous silicon cavity effort, we now achieve the fundamental thermal-noise-limited stability for a 6\ cm long silicon cavity cooled to 4\ K, reaching\ 6.5\texttimes10-17 from 0.8\ s to 80\ s. We also report for the first time, to the best of our knowledge, a clear linear dependence of the cavity frequency drift on incident optical power. The lowest fractional frequency drift of\ -3\texttimes10-19/s is attained at a transmitted power of 40 nW, with an extrapolated drift approaching zero in the absence of optical power. These demonstrations provide a promising direction to reach a new performance domain for stable lasers, with stability better than\ 1\texttimes10-17 and fractional linear drift below\ 1\texttimes10-19/s. BT - Optica DA - 2019-01 DO - 10.1364/OPTICA.6.000240 N2 - Crystalline optical cavities are the foundation of today\textquoterights state-of-the-art ultrastable lasers. Building on our previous silicon cavity effort, we now achieve the fundamental thermal-noise-limited stability for a 6\ cm long silicon cavity cooled to 4\ K, reaching\ 6.5\texttimes10-17 from 0.8\ s to 80\ s. We also report for the first time, to the best of our knowledge, a clear linear dependence of the cavity frequency drift on incident optical power. The lowest fractional frequency drift of\ -3\texttimes10-19/s is attained at a transmitted power of 40 nW, with an extrapolated drift approaching zero in the absence of optical power. These demonstrations provide a promising direction to reach a new performance domain for stable lasers, with stability better than\ 1\texttimes10-17 and fractional linear drift below\ 1\texttimes10-19/s. PY - 2019 EP - 240 T2 - Optica TI - Crystalline optical cavity at 4 K with thermal-noise-limited instability and ultralow drift UR - https://www.osapublishing.org/optica/fulltext.cfm?uri=optica-6-2-240\&id=405188 VL - 6 ER -