We designed a 935 nm repump beam path for use in a Ytterbium ion based optical clock.This state of the art clock work makes use multiple ensembles of ions trapped in separate RF potentials.Separate beams are amplified for coupling into the chip's integrated waveguides for precision pumping of ions out of dark states.The board acts as both a switch and modulation board.The pump beam is frequency locked to a wavemeter.Two beams are amplified and coupled into the integrated waveguides.The other two beams will be used for free space light delivery.Optical Atomic Clocks: Current atomic cesium clocks count in the range of microwave frequencies with uncertainties approaching 10 -16 [1].Optical atomic clocks based on ultra-stable laser addressing of narrow atomic linewidths achieve frequency uncertainties of ~10 -18 [2].These advanced clocks will impact technologies which rely on precision time keeping such as GPS, computing, and communication.
We designed a 935 nm repump beam path for use in a Ytterbium ion based optical clock.This state of the art clock work makes use multiple ensembles of ions trapped in separate RF potentials.Separate beams are amplified for coupling into the chip's integrated waveguides for precision pumping of ions out of dark states.The board acts as both a switch and modulation board.The pump beam is frequency locked to a wavemeter.Two beams are amplified and coupled into the integrated waveguides.The other two beams will be used for free space light delivery.Optical Atomic Clocks: Current atomic cesium clocks count in the range of microwave frequencies with uncertainties approaching 10 -16 [1].Optical atomic clocks based on ultra-stable laser addressing of narrow atomic linewidths achieve frequency uncertainties of ~10 -18 [2].These advanced clocks will impact technologies which rely on precision time keeping such as GPS, computing, and communication.
Outline • Introduction• Why trapped ions for miniaturization?• Miniaturized vacuum package: 1 cm 3 • Pulsed-mode ion clock performance • F-state trapping • Current focus: microwave optical double resonance continuous operation • Alternative ion clock: Alkali Mediated Atomic Clock • Conclusion Miniaturization with Long-Term and Environmental Stability • Achieve Cs Beam Clock performance in a mass and power constrained package • DARPA programs: • IMPACT: improved long-term stability • ACES: improved environmental stability Applications--Excellent timing for: • Rapid GPS acquisition, and GPS denied navigation and timing • Nano/pico (cube) satellites • Pulsed radio and spread spectrum communications Microsemi 5071A Miniature primary frequency standard Approved for Public Release, Distribution Unlimited Critical Elements of the 171 Yb + Clock Trap Electrodes Ions Yb Source Vacuum Package Control and Power Electronics Local Oscillator Magnetic Shield and Coil Repump (935 nm) Optical Pumping/ State Detection Laser (369 nm) Beam Combiner Fluorescence Collection Lens Fluorescence Detector Photo Multiplier Tube (PMT) Ionization UV Light
An optical clock or frequency standard based on the interrogation of an atomic transition in the optical domain, operates at ~1014Hz is capable of providing orders of magnitude better accuracy than the present primary standard of frequency or time operating in the microwave range. Optical transitions of an ions, confined within a radio frequency ion trap and laser cooled to ~mK temperature, provides better long term stability since they are free from Coulomb and intra-atomic interactions. Optical frequency standards have been realized with several ions, e.g.,199Hg+,171Yb+,115In+,88Sr+,40Ca+,27Al+and among those171Y+has multiple ultra-narrow optical transitions suitable for serving as frequency standards [1-2].
Optical clocks serve as the benchmark devices for the next-generation definition of the second and have significant applications in testing the theories beyong the standard models, dark matter research, and related fields.The ytterbium ion optical clock, featuring two clock transition lines, is among the most precise optical clocks with the lowest uncertainties.The National Institute of Metrology, China (NIM), initiated research on ytterbium ion optical clocks in 2021.Based on an end-cap ion trap, a vacuum system has been established.A 370 nm thirdharmonic fiber laser, along with 760 nm and 935 nm DFB lasers, ensures a stable operation of the optical system.To date, both the electric quadrupole and electric octupole clock transitions have been observed.A 2.8 Hz linewidth of the electric octupole transition has been achieved, with a stability of 1.7E-15 τ -1/2 after closed-loop locking.The uncertainties due to AC Starks shift from clock laser and second-order Doppler shifts are being evaluated, with an expected total uncertainty below 5E-18.
We report the development of a low-power, miniature Yb-171 ion clock at Sandia National Laboratories. This work is funded by the DARPA micro Position, Navigation, and Timing program under the Integrated Micro Primary Atomic Clock Technology (IMPACT) project. The ultimate goal is to develop a frequency standard that has frequency stability comparable to a commercial Cs beam standard, but with 100 to 1000 times smaller size and power consumption. The Yb-171 ion has a microwave clock traItem MIN :YXB4-01335-A112nsition at 12.6 GHz, and the natural linewidth of the clock resonance is expected to be less than 10-3Hz, which leads to a very high-Q clock resonance. An atomic clock using trapped ions is an excellent candidate for miniaturization because ions are well isolated from the environment independently of the size of the trap. Compared to optical traps for neutral atoms, the trapping depth of RF traps for ions is usually several orders of magnitude deeper. Therefore, the requirement for the vacuum level is more forgiving. We have successfully developed miniature ion-trap vacuum packages as shown in Fig. 1. Usually, a few microTorr of He buffer gas is introduced into each of our miniature ion-trap vacuum packages, which are sealed and passively pumped by non-evaporable getters. Using a sealed 3 cc ion-trap package, we were able to demonstrate long-term clock operation, with the stability reaching the 10-14range after a few days of integration [1].
In this paper, we propose a scheme of active ion optical clock with detailed pumping method, lasing states, output power, linewidth and light shift. Using 171Yb+ ions in a Paul Trap we propose to utilize a Fabry-Perot resonator to realize lasing of active optical frequency standards. The quantum-limited linewidth of active 171Yb+ ion optical clock is narrower than 1 mHz. Based on the mechanism and advantages of active optical clock at ion optical clock transition frequency, this new laser light source as a stable local oscillator, will be beneficial to the single-ion optical clock, which currently is the most accurate clock.
Optical frequency standards based on narrow absorptions in laser-cooled single trapped ions have recently begun to demonstrate stabilities that are competitive with cold atom fountain microwave standards. This paper presents a short review of the wider state-of-the-art development of these single cold trapped ion frequency standards, coupled with a more detailed account of recent results achieved at National Physical Laboratory in respect of single ion systems based on 88Sr+, 87Sr+ and 171Yb+. Narrow linewidth data for the optical clock quadrupole and octupole transitions respectively at 674 nm in 88Sr+ and 467 nm in 171Yb+, are presented, together with a discussion of current systematics and future projections. The potential for optical clock operation is outlined.