Attosecond precision multi-kilometer laser-microwave network

Abstract

Synchronous laser-microwave networks delivering attosecond timing precision are highly desirable in many advanced applications, such as geodesy, very-long-baseline interferometry, high-precision navigation and multi-telescope arrays. In particular, rapidly expanding photon-science facilities like X-ray free-electron lasers and intense laser beamlines require system-wide attosecond-level synchronization of dozens of optical and microwave signals up to kilometer distances. Once equipped with such precision, these facilities will initiate radically new science by shedding light on molecular and atomic processes happening on the attosecond timescale, such as intramolecular charge transfer, Auger processes and their impacts on X-ray imaging. Here we present for the first time a complete synchronous laser-microwave network with attosecond precision, which is achieved through new metrological devices and careful balancing of fiber nonlinearities and fundamental noise contributions. We demonstrate timing stabilization of a 4.7-km fiber network and remote optical–optical synchronization across a 3.5-km fiber link with an overall timing jitter of 580 and 680 attoseconds root-mean-square, respectively, for over 40 h. Ultimately, we realize a complete laser-microwave network with 950-attosecond timing jitter for 18 h. This work can enable next-generation attosecond photon-science facilities to revolutionize many research fields from structural biology to material science and chemistry to fundamental physics.

High-dynamic-range arrival time control for flexible, accurate and precise parametric sub-cycle waveform synthesis

“…than 1 : 5000. Any noise component at a frequency below 0.3 Hz can be attributed to thermal drifts of the optical table and optomechanic components, that can be compensated with proper environmental isolation [5]. We are convinced that the simplicity of the RAM setup allows for such a high degree of reproducibility.…”

“…Moreover, ultrafast time-resolved spectroscopy, that allows studying the dynamics of lightmatter interactions with picosecond to attosecond resolution, requires different pulses (with central frequencies ranging from less than a THz to a few EHz) to be synchronized within a fraction of their pulse durations. For instance, in large-scale photon-science facilities, such as X-ray free-electron lasers, the need to stabilize the arrival-time difference (ATD) between pulses generated by different sources has pushed the development of large-scale timing distribution systems [3,4] capable of generating an absolute reference with sub-femtosecond resolution (corresponding to hundreds of nm in length) over several km distances [5]. If it is not possible or practical to stabilize the ATD, time-tagging techniques have been demonstrated to measure the ATD with sub-fs resolution over a range of hundreds of fs [6], allowing to sort the data according to their ATD in post-processing.…”

Timing stabilization of solid-state, Yb-based laser system

“…The understanding of complex physical processes on ultra-short time scales, such as strong-field physics, and the design of novel optical sources, like spectrally combined OPCPAs [1], rely on complex laser systems and tight synchronization is often required between multiple optical pulse trains. Timing synchronization has been demonstrated in laser systems such as fiber based systems for timing links to sub-fs level at MHz repetition rate [2,3] and at low repetition rate for the fs short pulses out of the channels of a waveform synthesizer to 250 as [4]. These systems were limited in average power.…”

Comparing Optical Oscillators across the Air to Milliradians in Phase and 10−17 in Frequency

“…Furthermore, by exploiting the carrier-phase, this approach is able to continuously track changes in the relative optical phase of distant optical oscillators to 9 mrad (7 attoseconds) at 1-sec averaging, effectively extending optical phase coherence over a broad spatial network for applications such as correlated spectroscopy between distant atomic clocks.2 Applications of future optical clock networks include time dissemination, chronometric geodesy, coherent sensing, tests of relativity, and searches for dark matter among others [1][2][3][4][5][6][7][8][9][10][11][12][13][14].This promise has motivated continued advances in optical clocks and oscillators [15][16][17][18][19] and in the optical transfer techniques to network them. In particular, time-frequency transfer over fiberoptic networks has seen tremendous progress [1,7,[20][21][22][23]. However, many applications require clock networks connected via free-space links.…”

“…This promise has motivated continued advances in optical clocks and oscillators [15][16][17][18][19] and in the optical transfer techniques to network them. In particular, time-frequency transfer over fiberoptic networks has seen tremendous progress [1,7,[20][21][22][23]. However, many applications require clock networks connected via free-space links.…”