Overview of Frequency Metrology at NMIJ

Transcription

1 Overview of Frequency Metrology at NMIJ Kazumoto Hosaka Time and Frequency Division (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST) APMP TCTF 2014 Daejeon, KOREA 20 th - 23 rd September 2014

2 Outline The National Institute of Advanced Industrial Science and Technology (AIST) Structure of the national metrology institute of Japan (NMIJ) Time and Frequency Division Time Standards Section Frequency Measurement Systems Section Wavelength Standards Section

3 Structure of NMIJ The National Institute of Advanced Industrial Science and Technology (AIST) NMIJ

4 Structure of NMIJ Structure of NMIJ Director Deputy-Directors Principal Research Scientist Divisions Time & Frequency Lengths & Dimensions Mechanical Metrology Acoustics & Vibration Metrology Temperature & Humidity Fluid Flow Material Properties & Metrological Statistics Sections Time Standards Wavelength Standards Frequency Measurement Systems Length Standards Dimensional Standards Mass & Force Standards Pressure & Vacuum Standards Legal Weighing Metrology Acoustics & Ultrasonics Vibration & Hardness Thermometry Cryogenic Thermometry Radiation Thermometry Humidity Standards Gas Flow Standards Liquid Flow Standards Legal Flow Metrology Thermophysical Fluid Properties Metrological Statistics & Particle Measurement Divisions Electricity & Magnetism Electromagnetic Waves Quantum Radiation Inorganic Analytical Chemistry Organic Analytical Chemistry Materials Characterization Legal Metrology Dissemination Technology Metrology Management Center Sections Electricity Standards Section 1 Electricity Standards Section 2 High Frequency Standards Field Strength Standards Laser Standards Optical Radiation Ionizing Radiation Radioactivity & Neutron Inorganic Standards Environmental Standards Organic Standards Polymer Standards Biomedical Standards Surface & Thin Film Standards Nanopore Standards Calibration & Verification Pattern Approval Policy & Planning Office Service & Quality Office International Metrology Cooperation Office Metrology Training

5 Time Standards Section Members: T. Ikegami K. Hagimoto S. Yanagimachi A. Takamizawa T. Tanabe I. Hirano Main tasks Cs atomic fountains Cryocooled cryogenic sapphire oscillator Calibration service: phase noise of microwave oscillator

6 6 Atomic fountains at NMIJ 3 fountains NMIJ-F1: Long term operation at uncertainty ~ Now being rebuilt. Frequenly report of data to BIPM Reference for NMIJ-F2 and optical lattice clocks NMIJ-F2: Uncertainty < Now being developed. High contribution to TAI More precise reference for optical lattice clocks Truncated beam fountain: Proof of principle, uncertainty Collisional shift and frequency stability New proposal: A. Takamizawa et al., PRA 82, (2010).

7 7 NMIJ-F2 Ramsey cavity Selection cavity Detection beam Ion pump 55 l/s 10 cm C-field coil Magnetic shielding Detection chamber NEG pump Microwave cavities which are part of the vacuum vessel (S. R. Jefferts et al., Proc. of the 1998 IEEE FCS, p. 6) Decrease of the uncertainty caused by microwave power dependence High power laser 60 mw per cooling-beam Optical pumping to m F =0 (K. Szymaniec et al., Appl. Phys. B, to be published.) Increase in detected atoms ( atoms) Improvement of frequency stability Cs Cooling beam Trapping chamber Helmholtz coils Cryocooled Sapphire oscillator (cryocso) (J. G. Hartnett et al., Appl. Phys. Lett. 100, (2012).) Local oscillator with <10-15 at 1s Improvement of frequency stability

8 Transition Probability National Institute of Advanced Industrial Science and Technology 8 Ramsey fringes Interrogation time: 0.69 s Frequency detuning (Hz) The narrow fringes are observed by virtue of the quite long interrogation time. Width : 0.7 Hz, Contrast: 0.95

9 9 Frequency stability Local oscillator and reference: Cryocooled Sapphire Oscillator The Dick effect is eliminated. Reach the QPN limit to within 11% Only NMIJ-F2 and SYRTE-FOM reach below t -1/2 in the fountains using vapor-loaded optical molasses. (A. Takamizawa et al., IEEE UFFC, 61, (2014).)

10 Frequency shifts (i) 2nd-order Zeeman shift Homogeneous within 0.8 nt 2nd-order Zeeman shift = The long term variation has not been evaluated yet. (ii) Collisional shift Good linearity The type B uncertainty, , will be smaller by longer measurement. The type A uncertainty in the alternative operation between Natom = 1, 3 = t -1/2

11 Preliminary error budget ( :Not completed yet) NMIJ-F2 can be now compared with TAI and the other PFSs with level. (A. Takamizawa et al., IEEE IM, submitted.)

12 Allan deviation Cryocooled Cryogenic Sapphire Oscillator We modified one of the 2 liquid He CSO to a cryocooled CSO in cooperation with Prof.J.Hartnett (University of Adelaide). The structure of a Cryocooled CSO Guess of the frequency stability of a single cryocso (2014.4) NMIJ CryoCSO vs Hydrogen Maser NMIJ CryoCSO vs liquid He CSO UWA CryoCSO (Hartnett, Parker, Ivanov et al., IEEE UFFC 2013) Averaging time (s) The frequency stability is worse by 1 order of magnitude than that of the cryocooled CSO in UWA. The design of the inner can is not optimized because we used the inncer can of the liq.he CSO. National Institute of Advanced Industrial Science and Technology 12

13 Frequency Measurement Systems Section Members: M. Amemiya K. Watabe T. Suzuyama M. Wada A. Okuda Main tasks Upgrading UTC(NMIJ) Time and frequency transfer, such as GPS carrier phase, TWSTFT, VLBI, optical fibre, etc. Calibration service of time and frequency and its R&D work

14 UTC(NMIJ) generation system and time transfer link UTC(NMIJ) is generated by reference signal from one hydrogen maser steered by an AOG. Clocks at NMIJ - 4 hydrogen masers 1 RH401A made by Anritsu 1 VCH-1003M made by VREMYA 1 SD1T01A made by Anritsu 1 CH1-75A made by KVARZ CH1-75A is the reference oscillator of UTC(NMIJ) Cs clocks 5071A with high performance beam tube Time Transfer Link - UTC PPP (GPS carrier phase) using Z12-T: main time transfer tool - TWSTFT : backup tool National Institute of Advanced Industrial Science and Technology

15 Measurement system for UTC(NMIJ)

16 UTC-UTC(NMIJ) [ns] National Institute of Advanced Industrial Science and Technology 50 UTC-UTC(NMIJ) /01/ /04/ /07/ /10/ /12/ /04/ /07/ /09/30 Year Month Day (yyyy/mm/dd)

17 NMIJ s earth station configuration air-conditioned storehouse chamber Europe link Asia link Up&Down converter and SSPA

18 Optical Carrier Transfer System at NMIJ Experimental Set Up

19 Allan Deviation, σ y (τ) National Institute of Advanced Industrial Science and Technology Frequency stability of Optical Carrier Transfer System Optical Clock Optical fiber (90 km spool) Averaging Time, τ(sec)

20 Remote Frequency Calibration Service by NMIJ (1) GPS UTC(NMIJ) AIST(NMIJ) GPS Receiver jcss Calibration Certificate Registered establishment site Data server Web Published Data Data Download Internal oscillator is synchronized to UTC(NMIJ) with the NMIJ web site data Data Upload Internet

21 Remote Frequency Calibration Service by NMIJ (2) Scope of calibration CMC (k=2) Condition Averaging time:1day Baseline:50 km 5 MHz, 10 MHz Averaging time:1day Baseline:500 km Averaging time:1day Baseline:1600 km Number of users: 17 (on the rise year by year) More content about remote frequency calibration will be presented in the Workshops on Sep. 20.

22 Wavelength Standards Section Members: K. Hosaka F.-L. Hong A. Onae H. Inaba M. Yasuda D. Akamatsu S. Okubo Main tasks Yb and Sr optical lattice clocks Narrow linewidth lasers Optical frequency combs

23 Yb and Sr optical lattice clocks at NMIJ Yb1/Yb2 Yb/Sr Yb2/Sr Yb optical lattice clock (2.0) Hz (M. Yasuda, APEX 5, (2012)) (18) (D. Akamatsu, Opt. Express 22, 7898 (2014)) Yb optical lattice clock Sr optical lattice clock (1.6) Hz (D. Akamatsu, APEX 7, (2014)) 1 st cooling transition 1 S 0-1 P 1 2 nd cooling transition 1 S 0-3 P 1 clock transition 1 S 0-3 P 0 magic wavelength vapor pressure at 400 Yb 399 nm 556 nm 578 nm 759 nm 1.6x10-4 Torr Sr 461 nm 689 nm 698 nm 813 nm 4.4x10-4 Torr Sr-Yb dual optical lattice clock

24 2nd phase of research and results 2012 Absolute frequency measurement of Yb OLC (Metrologia 50, 119) (Appl. Phys. Express 5, ) (PRL 103, ) USA Korea Japan NMIJ: Absolute frequency uncertainty Yb clock uncertainty: Appl. Phys. Express 5, (2012)

25 Sr-Yb dual optical lattice clock at NMIJ/AIST Build up 87 Sr/ 171 Yb optical lattice clocks in a new chamber. Motivation 1) Contribution to the Sr lattice clock community; 2) As a second optical clock to be used for the evaluation of the Yb lattice clock; 3) Measurement of the Sr/Yb frequency ratio with an uncertainty beyond the Cs limit; 4) Contribution to the experimental demonstration of alpha variation. National Institute of Advanced Industrial Science and Technology D. Akamatsu, et al., Opt. Express 19, 2046 (2011).

26 Frequency Hz National Institute of Advanced Industrial Science and Technology Absolute frequency measurement of Sr OLC NICT(JPN) JILA(USA) NMIJ(JPN) SYRTE(FRA) PTB(GER) Univ. Tokyo(JPN) Effect Correction Uncertainty (10-16 ) (10-16 ) Blackbody radiation AC Stark (lattice) AC Stark (probe) nd order Zeeman Collision Gravitation Servo error Sr systematics total UTC(NMIJ) UTC(NMIJ)-TAI TAI-SI Total f Sr = (1.6)Hz D. Akamatsu, APEX 7, (2014)

27 Frequency ratio measurement of 171 Yb and 87 Sr (a) (b) (a) Frequency ratio measurements of Sr and Yb optical lattice clocks. Error bars are statistical. Data shown in this figure include the systematic corrections. (b) Allan standard deviation of the frequency ratio measurement for the measurement number 3 in (a). National Institute of Advanced Industrial Science and Technology D. Akamatsu, Opt. Express 22, 7898 (2014)

28 Applications to optical lattice clocks using narrow linewidth combs Dn~1 Hz Nd:YAG 1Comb is phase locked to the ultra-stable laser at 1064 nm. n Frequency comb High-finesse optical cavity at 1064 nm 2Continuous wave lasers are phase locked to the comb. n 171 Yb Yb lattice clock Clock laser (578 nm) Sr lattice clock 2 nd cooling laser (689 nm) PDH lock Ultra stable laser at 1064 nm The comb transfers the linewidth to other lasers at some wavelengths. 87 Sr Sr lattice clock Clock laser (698 nm) National Institute of Advanced Industrial Science and Technology H. Inaba, et al., Opt. Express 21, 7891 (2013).

29 Frequency stability of narrow linewidth lasers Beat between narrow linewidth lasers 1 Comb is phase locked to the ultra-stable laser at 1064 nm. ~ Frequency comb n 2 Beat between 1.5 mm cw laser and comb is observed.

30 Excitation ratio Atomic spectroscopy Successful demonstration of the spectroscopy with laser linewidth transfer 1 S 0 m F =+1/2 3 P 0 m F =+1/2 1 S 0 m F = -1/2 3 P 0 m F = -1/2 171 Yb 87 Sr 1 S 0 m F =+9/2 3 P 0 m F =+9/ ~ 50Hz Hz Frequency (Hz) The laser stabilised to the cavity at 1064 nm via the high-speed controllable fibre comb. H. Inaba, et al., Opt. Express 21, 7891 (2013). National Institute of Advanced Industrial Science and Technology D. Akamatsu, et al., Appl. Phys. Express 7, (2014).

31 Relative line width of the fiber comb Beat spectrum 75 db/hzrbw (S/N of coherent spike) Phase noise 0.34 rad (Integrated RMS phase) Energy concentration of ~ 94%. Beat spectrum (Enlarged) < 30 mhz (linewidth) Frequency stability 5 s (Allan deviation) K. Iwakuni et al., Opt. Express 20, (2012). National Institute of Advanced Industrial Science and Technology