A5072151059- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Fiber Laser Technologies
- Quantum optics and atomic interactions
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Sensor Technology
- Spectroscopy and Laser Applications
- Optical Network Technologies
- Semiconductor Lasers and Optical Devices
- Cardiovascular Syncope and Autonomic Disorders
- Radioactive Decay and Measurement Techniques
- Advanced Fiber Optic Sensors
- Advanced Photonic Communication Systems
- GNSS positioning and interference
- Laser Design and Applications
- Quantum Information and Cryptography
- Hemodynamic Monitoring and Therapy
- Seismic Waves and Analysis
- Optical and Acousto-Optic Technologies
- Network Time Synchronization Technologies
- Non-Invasive Vital Sign Monitoring
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Solid State Laser Technologies
Istituto Nazionale di Ricerca Metrologica
2016-2025
National Institute of Standards and Technology
2002-2019
Istituto di Radioastronomia di Bologna
2019
Agenzia Spaziale Italiana
2019
Torino e-district
1961-2016
Polytechnic University of Turin
1996-2013
Ferrari (Italy)
1997-2008
Istituto Nazionale di Fisica Nucleare, Galileo Galilei Institute for Theoretical Physics
1997-2008
National Institute of Standards
2007
University of Perugia
1988
The evaluation procedure of a new laser-cooled caesium fountain primary frequency standard developed at the National Institute Standards and Technology (NIST) is described. standard, NIST-F1, described in some detail typical operational parameters are discussed. Systematic biases for which corrections made - second-order Zeeman shift, black-body radiation gravitational red shift spin-exchange discussed detail. Numerous other shifts evaluated, but so small this type that not their effects. We...
Submarine fiber optic earthquake detection Seismic networks detect earthquakes and are common on continents, where they easy to install. However, most of Earth's surface is under the oceans, placing seismometers difficult. Marra et al. now find that ordinary submarine telecommunication cables can be used earthquakes. Small strain changes associated with passage seismic waves were detected laser light sent through in-use by ultrastable lasers. This strategy could turn intercontinental into...
We demonstrate a novel way of synthesizing spin-orbit interactions in ultracold quantum gases, based on single-photon optical clock transition coupling two long-lived electronic states two-electron ^{173}Yb atoms. By mapping the onto effective sites along synthetic "electronic" dimension, we have engineered fermionic ladders with magnetic flux an experimental configuration that has allowed us to achieve uniform fluxes lattice minimal requirements and unprecedented tunability. detected...
We report the first accuracy evaluation of NIST-F2, a second-generation laser-cooled caesium fountain primary standard developed at National Institute Standards and Technology (NIST) with cryogenic (liquid nitrogen) microwave cavity flight region. The 80 K atom interrogation environment reduces uncertainty due to blackbody radiation shift by more than factor 50. Also, Ramsey exhibits high quality (>50 000) this low temperature, resulting in reduced distributed phase shift. NIST-F2 has...
Quantum mechanics allows distribution of intrinsically secure encryption keys by optical means. Twin-field quantum key is one the most promising techniques for its implementation on long-distance fiber networks, but requires stabilizing length communication channels between parties. In proof-of-principle experiments based spooled fibers, this was achieved interleaving with periodical stabilization frames. approach, longer duty cycles streaming come at cost a looser control channel length,...
Abstract This paper outlines the roadmap towards redefinition of second, which was recently updated by CCTF Task Force created in 2020. The main achievements optical frequency standards (OFS) call for reflection on but open new challenges related to performance OFS, their contribution time scales and UTC, possibility comparison, knowledge Earth’s gravitational potential ensure a robust accurate capacity realize definition at level 10 −18 uncertainty. mandatory criteria be achieved before...
For the past 50 years, atomic standards based on frequency of cesium ground-state hyperfine transition have been most accurate time pieces in world. We now report a comparison between fountain standard NIST-F1, which has evaluated with an inaccuracy about 4 x 10(-16), and optical ultraviolet single, laser-cooled mercury ion for fractional systematic uncertainty was below 7.2 10(-17). The absolute measured versus to be 1,064,721,609,899,144.94 (97) Hz, statistically limited total 9.1 10(-16)...
We report tests of local position invariance and the variation fundamental constants from measurements frequency ratio 282-nm $^{199}\mathrm{Hg}^{+}$ optical clock transition to ground state hyperfine splitting in $^{133}\mathrm{Cs}$. Analysis two clocks, extending over 6 yr at NIST, is used place a limit on its fractional $<5.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ per change normalized solar gravitational potential. The same also obtain 20-fold improvement previous...
A practical problem that arises when using acousto-optic modulators (AOMs) to scan the laser frequency is dependence of beam diffraction angle on modulation frequency. Alignment problems with AOM-modulated beams can be effectively eliminated by AOM in double-pass configuration, which compensates for deflections. On a second pass through AOM, its polarization rotated 90° deflected back such it counterpropagates incident and separated from input polarizing splitter. Here we present our design...
The phenomenon of coherent population trapping in alkali-metal atoms is analyzed by means a perturbation approach. Closed form transparent solutions are obtained for the coherences existing within system and populations ground levels excited state. presence dark lines microwave emission from state made explicit. Experimental results that confirm theoretical calculations reported case cesium buffer gas. Conclusions drawn connection with application to field atomic frequency standards.
We report on the implementation and metrological characterization of a vapor-cell Rb frequency standard working in pulsed regime.The three main parts that compose clock, physics package, optics electronics, are described detail paper.The prototype is designed optimized to detect clock transition optical domain.Specifically, reference atomic transition, excited with Ramsey scheme, detected by observing interference pattern laser absorption signal.The analysis includes observation signal...
We report on the first direct observation of fast spin-exchange coherent oscillations between different long-lived electronic orbitals ultracold $^{173}$Yb fermions. measure, in a model-independent way, strength exchange interaction driving this process. This allows us to retrieve important information inter-orbital collisional properties atoms and paves way novel quantum simulations paradigmatic models two-orbital magnetism.
For almost two decades, caesium fountain primary frequency standards (PFS) have represented the best realization of definition second in International System units. Their accuracy has progressively improved with time, reaching a few parts 1016. In this paper, we present evaluation ITCsF2, new Cs PFS developed at Italian National Metrological Institute, designed to be operated cryogenic temperature reduce blackbody radiation shift. The short-term stability ITCsF2 is 2 × 10−13τ−1/2 when high...
We present laser results obtained from a Dy³⁺-Tb³⁺ co-doped LiLuF₄ crystal, pumped by blue emitting InGaN diode, aiming for generation of compact 578 nm source. exploit the yellow Dy³⁺ transition ⁴F(9/2)⇒⁶H(13/2) to generate emission. The lifetime lower level is quenched, via energy transfer, Tb³⁺ ions in fluoride crystal. report growth technique, spectroscopic study, and room temperature continuous wave hemispherical cavity at 574 nm, with highly reflective output coupler nm. A very...
Abstract We describe a VLBI experiment in which, for the first time, clock reference is delivered from National Metrology Institute to radio telescope using coherent fibre link 550 km long. The consisted of 24-hours long geodetic campaign, performed by network European telescopes; one those (Medicina, Italy) local was alternated with signal generated an optical comb slaved fibre-disseminated signal. quality results obtained this facility and similar: interferometric fringes were detected...
Among the most powerful techniques for exploration of Universe is very long baseline interferometry (VLBI), which based on simultaneous observation radio sources in sky with arrays distant ground-based antennas. One effects currently limiting its ultimate sensitivity phase-instability reference clocks adopted at each antenna. This term can be made negligible delivering same clock signal to multiple telescope sites using optical fibers. We realized such an infrastructure by disseminating a...
Abstract The impact of noise sources in real‐world implementations twin‐field quantum key distribution (TF‐QKD) protocols is investigated, focusing on phase from photon and connecting fibers. This work emphasizes the role laser quality, network topology, fiber length, arm balance, detector performance determining rates. Remarkably, it reveals that leading TF‐QKD are similarly affected by despite different mechanisms. study demonstrates duty cycle improvements over a factor two through...
We performed a two-way remote optical phase comparison on fiber. Two frequency signals were launched in opposite directions an fiber and their phases simultaneously measured at the other end. In this technique, noise is passively canceled, we compared two frequencies ultimate 10(-21) stability level. The experiment was 47 km that part of metropolitan network for Internet traffic. technique relies synchronous measurement ends link, which here by digital electronics. This scheme offers some...
Abstract We report the absolute frequency measurement of unperturbed optical clock transition 1 S 0 – 3 P in 171 Yb performed with an lattice standard. Traceability to International System Units is provided by a link Atomic Time. The result 518 295 836 590 863.61(13) Hz relative standard uncertainty , obtained operating our intermittently for 5 months. contributes systematic .
Bidirectional phase-stabilized optical fiber links allow state-of-the-art clocks to be compared on a continental scale.However, intercontinental comparisons are still based satellite techniques, preventing from being without degradation.We performed the first frequency transfer experiment over submarine links, measuring levels of environmentally induced noise substantially lower than for on-land links.From these measurements, we predict stability that can achieved transoceanic links.We also...
We demonstrate the enhancement and optimization of a cold strontium atomic beam from two-dimensional magneto-optical trap (2D MOT) transversely loaded collimated by adding sideband frequency to cooling laser. The parameters beams are scanned achieve maximum flux compared with Monte Carlo simulations. obtain 2.3 times larger total brightness increase factor 4 conventional, single-frequency 2D MOT for given power 200 mW. show that sideband-enhanced can reach loading-rate performances...