Related papers: Optical frequency divider with division uncertaint…
Atomic clocks have been transformational in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Next-generation optical atomic clocks can extend…
We consider the frequency shift in optical lattice clocks which arises from the coupling of the electronic motion to the atomic motion within the lattice. For the simplest of 3-D lattice geometries this coupling is shown to only affect…
The absolute frequency of the 1S0-3P0 clock transition of 87Sr has been measured to be 429 228 004 229 873.65 (37) Hz using lattice-confined atoms, where the fractional uncertainty of 8.6x10-16 represents one of the most accurate…
Optical-frequency synthesizers are lasers stabilized and programmed from a microwave clock for applications, especially in fundamental measurements and spectroscopy, optical-communication links, and precision sensing of numerous physical…
Demands from several areas of science and technology have lead to a worldwide search for accurate optical clocks with an uncertainty of 1 part in $10^{18}$, which is $10^{3}$ times more accurate than the present day cesium atomic clocks…
The telecommunications industry's deployment of billions of kilometers of optical fiber has created a vast global network that can be exploited for additional applications such as environmental sensing, quantum networking and international…
We identify two metastable excited states in Sm$ ^{10+} $ highly charged ion as candidates for high accuracy optical clocks. Several atomic properties relevant to optical clock development are calculated using relativistic many-body…
We present a new evaluation of an 87Sr optical lattice clock using spin polarized atoms. The frequency of the 1S0-3P0 clock transition is found to be 429 228 004 229 873.6 Hz with a fractional accuracy of 2.6 10^{-15}, a value that is…
The transfer of high-precision optical frequency signals over free-space links, particularly between ground stations and satellites, will enable advances in fields ranging from coherent optical communications and satellite Doppler ranging…
Laser frequency combs based on erbium-doped fiber mode-locked lasers have shown great potential for compact, robust and efficient optical clock comparisons. However, to simultaneously compare multiple optical clock species, fiber laser…
Recently invented and demonstrated, optical lattice clocks hold great promise for improving the precision of modern timekeeping. These clocks aim at the 10^-18 fractional accuracy, which translates into a clock that would neither lose or…
We present a system of two independent strontium optical lattice standards probed with a single shared ultra-narrow laser. The absolute frequency of the clocks can be verified by the use of Er:fiber optical frequency comb with the…
Neutral quantum absorbers in optical lattices have emerged as a leading platform for achieving clocks with exquisite spectroscopic resolution. However, the studies of these clocks and their systematic shifts have so far been limited to…
We describe the current status of the Ca optical frequency standards with laser-cooled neutral atoms realized in two different laboratories for the purpose of developing a possible future optical atomic clock. Frequency measurements…
The realization of ultra stable optical frequency transmission through fiber networks is critical for advancing global optical frequency standards and enabling applications such as redefining the second in the International System of Units,…
We report an optical link of 540 km for ultrastable frequency distribution over the Internet fiber network. The stable frequency optical signal is processed enabling uninterrupted propagation on both directions. The robustness and the…
Optical time-frequency transfer establishes the metrological linkage in large-scale clock networks, which facilitates various applications. Fiber-based transfer benefits from the abundant deployment of fiber infrastructures to achieve this…
Time and frequency transfer lies at the heart of the field of metrology. Compared to current microwave dissemination such as GPS, optical domain dissemination can provide more than one order of magnitude in terms of higher accuracy, which…
We have measured the absolute frequency of the optical lattice clock based on $^{87}$Sr at PTB with an uncertainty of $3.9\times 10^{-16}$ using two caesium fountain clocks. This is close to the accuracy of today's best realizations of the…
We introduce a novel concept for optical frequency measurement and division which employs a Kerr-lens mode-locked laser as a transfer oscillator whose noise properties do not enter the measurement process. We experimentally demonstrate,…