Boulder Flatirons
– Thinking About Measurements – Standards, Accuracy, Repeatability Precision, and all that Jazz … John L Hall JILA University of Colorado Boulder CO 80309-0440
[email protected] http://jila.colorado.edu/hall/
Complex Quantum Systems Seminar University of Texas, Austin 24 March 2011
Lasers for Precision Measurement focusing on the start of 49 years of Laser fun Frequencies, Lengths, & Fundamental Physics John L. Hall
Jun Ye
JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado at Boulder http://Jila.Colorado.edu/hall/
RS Symposium on a New SI ? London UK 24 January 2011
http://HallStableLasers.com
NI$T N$F NA$A ONR
Peter C. Doherty Columbia University Press New York 2006
Photo 1943, Brisbane Laureate 1996
NO GUARANTEE NO REFUND
Metrology, the Mother of Science Today’s Symposium features Length and Time/Frequency Ell, Braunschweig Metre Bar, Paris Cadmium Lamp A.A.Michelson Nobel Prize A.A.M. ±4 x10-7 Krypton Lamp ±4 x10-9 Methane-Stab. Laser ±1 x10-11 c adopted constant 0
Day Mean Solar Day Tropical Astronomical Year 1960 Cesium Second Cs Fountain Clock ±1 x10-15 Hg+ -stabilized Laser ±1 x10-15
~1600 ~1875 1887 1907 1960 1972 1983
1875 1967 ~2000 2004
Length – Depends on: Inter-atomic distances, E & M/ Quantum Mechanics
Frequency – Depends on: Internal electronic energy differences E & M/ Quantum Mechanics Fine-Structure Constant
1875
1889 1960
BIPM’s Kg and Metre ProtoTypes Metre bar replaced in 1960 by light-wave definition – Krypton 605.7 nm line (Isotope 86) First optical fringe measurement by A. A. Michelson 1887
Nobel Prize 1907
Optical Comb Thanks to Howard Layer
My thanks to H P Layer !
The earth has been measured as a basis for a permanent standard of length, and every property of metals has been investigated to guard against any alteration of the material standards when made. To weigh or measure any thing with modern accuracy, requires a course of experiment and calculation in which almost every branch of physics and mathematics is brought into requisition. Yet, after all, the dimensions of our earth and its time of rotation, though, relatively to our present means of comparison, very permanent, are not so by any physical necessity. The earth might contract by cooling, or it might be enlarged by a layer of meteorites falling on it, or its rate of revolution might slowly slacken, and yet it would continue to be as much a planet as before. But a molecule, say of hydrogen, if either its mass or its time of vibration were to be altered in the least, would no longer be a molecule of hydrogen. If, then, we wish to obtain standards of length, time, and mass which shall be absolutely permanent, we must seek them not in the dimensions, or the motion, or the mass of our planet, but in the wave-length, the period of vibration, and the absolute mass of these imperishable and unalterable and perfectly similar molecules. —James Clerk Maxwell, 1870.9.15 (Liverpool address) [Niven “papers” 1890 , p. 225 ] Quoted in Flowers, J Science 19 November 2004: Vol. 306 no. 5700 pp. 1324-1330 DOI: 10.1126/science.1102156
Table 1. SI base units Base quantity SI base unit _________________________________ __________________________ Name Symbol Name Symbol Length l, x, r, etc. metre m mass m kilogram kg time, duration t second s electric current I, i ampere A thermodynamic temperature T kelvin K amount of substance n mole mol luminous intensity Iv candela cd
Ref: http://physics.nist.gov/Pubs/SP330/sp330.pdf
Table 7. Non-SI units whose values in SI units must be obtained experimentally Quantity Name of unit Symbol for unit Value in SI units (a)
Units accepted for use with the SI energy electronvolt eV 1 eV = 1.602 176 53 (14) × 10−19 J mass dalton, Da 1 Da = 1.660 538 86 (28) × 10−27 kg unified atomic mass unit u 1 u = 1 Da length astronomical unit ua 1 ua = 1.495 978 706 91 (6) × 1011 m Natural units (n.u.) speed n.u. of speed c0 299 792 458 m/s (exact) (speed of light in vacuum) action n.u. of action ħ 1.054 571 68 (18) × 10−34 J s (reduced Planck constant) mass n.u. of mass me 9.109 3826 (16) × 10−31 kg (electron mass) 2 time n.u. of time ħ/(me c0 ) 1.288 088 6677 (86) × 10−21 s
Atomic units (a.u.) charge a.u. of charge, e 1.602 176 53 (14) × 10−19 C (elementary charge) mass a.u. of mass, me 9.109 3826 (16) × 10−31 kg (electron mass) action a.u. of action, ħ 1.054 571 68 (18) × 10−34 J s (reduced Planck constant) length a.u. of length, bohr a0 0.529 177 2108 (18) × 10−10 m (Bohr radius) energy a.u. of energy, hartree Eh 4.359 744 17 (75) × 10−18 J (Hartree energy) time a.u. of time ħ/Eh 2.418 884 326 505 (16) × 10−17 s
Determining the Number of Atoms in a Mole by Counting!
B. Andreas + 29 others, 8 Institutes in 8 countries
“The Metre is the length of the path travelled by light (in vacuum) in 1/299 792 458 of a second” ie., c = 299 792 458 m/s, exactly CGPM 1983
Metre ReDefinition & Demotion
3.39m tunable Laser locked to 30 m Cavity
CH4 – stabilized HeNe 3.39m Laser
Some Friends in the UltraStable Laser Game – – – – – – – – – –
Bergquist group at NIST Boulder - present champs Oates, Hollberg et al NIST Bouder Gill, Webster & Co, at NPL, sub-Hertz linewidth Walther, Nevsky, at MPQ Hänsch group at MPQ Tamm, Peik at PTB Riehle group at PTB Katori at Tokyo + Hong at AIST Dube, Madej at NRC SYRTE optical clock group, Paris
– Please forgive omissions – I was retired for a while… and will soon be old enough to just forget stuff !
5/16/1960 Hughes Res. Ted Maiman Ruby Laser NonLinear Effects Pulsed Lasers
12/12/1960 Bell Labs Ali Javan - HeNe Stable Lasers Ultra-Sensitivity Techniques
Infrared and Optical Masers by Arthur L. Schawlow & C. H. Townes Physical Review 1958
The Amazing Laser Epoch Begins -- 1960
Javan, Bennett, Herriott cw gas Lasers 1960+
Optical Beats
NBS CH4 Frequency 88 THz
cw Lasers Pulsed Lasers
Metre Re-definition
1972
Cw Stable Solid-State Lasers
COMBs
1983 1990’s
2-H Gen. Burn Air Razor Sparks Blades
Ted Maiman Ruby Laser 1960
sub-HertzAccuracy Frequency Measurement
kJ Lasers
t
2000
fs ModeLocked Lasers
Tera-Watt Table-Top Laser
50 Years of the Laser Epoch
Sub-Hertz Linewidth fs Combs
INSPIRATION of the YOUNG
Hearing the lasers’ Optical Beat as an audio whistle completely changed my research career!
Ali Javan inventor/designer of the Helium-Neon Laser First oscillations: 12 Dec.1960, Bell Labs Demonstration of Optical Heterodyne Beats 1961
Saturated Neon Absorption inside a 6328-Å Laser Paul H. Lee and Michael J. Skolnick
CH4 Saturated Absorption at 3.39 m Narrow ! Strong !
~August 1968
Barger and Hall
A New Wavelength Standard? !!!
HeNe laser fringes (at 3.39 m)
Krypton fringes (at 605.7 nm) 4 x10-9 in 300 s !
Frequency Scan R. L. Barger and JLH ’71 APL 22, 196 (1973)
Hall, Bender, Faller, 1968.Quantum Electronics Conference, QE-1, p371
J Hall at entrance to Poorman’s Relief Gold Mine (site of JILA 30 m evacuated interferometer, Boulder ~1968)
How can we multiply frequency by 10-thousand fold?
Ken Evenson (1972) + Joe Wells, Don Jennings … x14
x6 x12 x3 = 3024
1 electronic stage + 3 Lasers stabilized
Measures
the
CO2 Laser 32 THz (9.3 micrometers)
The First NBS Optical Frequency Chain NBS (NIST): measurement of speed of light, 1972
J. Wells
K. Evenson
J. L. Hall & J. Ye, “NIST 100th birthday”, Optics & Photonics News 12, 44, Feb. 2001
Frequency spectrum in optical frequency synthesis 1015 1014 1013
Log Frequency (Hz)
1012 1011 1010
107
H, Hg+ Ca I2 Rb, Cs
Molecular overtones
H2O
CH4 OsO4
CO2
Visible
Lasers
MIM or Schottky diode
CH3OH HCOOH HCN
BWO
Cs
Crystal oscillator
Microwave oscillators, Klystrons, etc.
W-Si wave diode
The NBS Speed of Light Program:
=88 376 181 627. kHz ± 50.
c=
Evenson’s Team K.M.E., J.S. Wells, F.R. Petersen B.L.Danielson, & G.W. Day And D. A. Jenning$
=3 392.231 390 nm ± .000 01
c = 299, 792, 457.4 m/s
JILA Team R. L.Barger & J. L. Hall
Our Finest Product !
±1.1 Phys. Rev. Lett. 29, 1346 (1972)
Redefinition of the International SI Metre 1960: Metre is 1 650 763.73 waves of Kr orange line
THE SPEED OF LIGHT C = 299 792 458 m/s (exact) THE METRE DEFINITION (1983) The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.
17th Conférence Général des Poids et Mesures, Paris, October 1983
Re-Definition and Demotion of the Meter in SI
NICE-OHMS Intra-cavity Dispersion Optical Lattice Trap trapping w Magic Wavelength
Ye, Ma, Hall ’96 Katori, Ye ‘05
Venya Chebotayev & Ken Evenson
“How are we going to measure those optical frequencies?”
Lindy, Vera, Ken, & Venya
Celebrating the new Hall_Labs, April 1988
Talking Science in Munich - 2005
Jan, Thomas Udem
Ted Ron Drever
The Optical Comb Concept T. W. Hänsch, V. P. Chebotayev ~1977
1960 Hughes Res. Ted Maiman Ruby Laser NonLinear Effects Pulsed Lasers
1960 Bell Labs Ali Javan - HeNe Stable Lasers Ultra-Sensitivity Techniques
Phase-Stabilization Techniques fs Lasers Ultra-NonLinearity SuperContinuum
Update to 1999
Hänsch group – Garching Hall group - Boulder
the Optical Comb - 39 years Later
Serious nonlinear optics R. Windeler
J.K Ranka, R. S. Windeler, A. Stenz, Opt. Lett. 25, 25 (Jan. 2000)
Microstructured fiber dispersion zero at ~800 nm pulses do not spread continuum generation via self-phase modulation
Lucent Technologies
Detected Power (dBm)
-30
After fiber -40 -50 -60
Pre-fiber (Ti:S)
-70
400
600
800 1000 Wavelength (nm)
1200
Optical Frequency is Synchronized with the Pulse Repetition Frequency Each pulse has the same shape …
The Optical Frequency Tool for all Seasons Comb Another Tool for All Seasons
From Ye, Schnatz, & Hollberg 2003
“Frequency Ratio of Al+ and Hg+ Single-Ion Optical Clocks; Metrology at the 17th Decimal Place” T. Rosenband,* D. B. Hume, P. O. Schmidt,† C. W. Chou, A. Brusch, L. Lorini,‡ W. H. Oskay, R. E. Drullinger, T. M. Fortier, J. E. Stalnaker,∥ S. A. Diddams, W. C. Swann, N. R. Newbury, W. M. Itano, D. J. Wineland, J. C. Bergquist, all at NIST Boulder p1808, 28 MARCH 2008 VOL 319 SCIENCE www.sciencemag.org
5/16/1960 HughesComb Res. Applications – Jun Ye 12/12/1960 Ted Maiman Bellmeasurement Labs • Optical frequency Ruby Laser Ali Javan - HeNe
Group
• Measure and Improve Stable Lasers NonLinear • LISA Gravitational Wave Space Interferometer Stable Lasers Effects • Synchronize Lasers • Time/Frequency TransferUltra-Sensitivity Pulsed Lasers Techniques • Synchronize Accelerators & Radio Telescopes • Optical Frequency Standards • Possible Variation of Physical “Constants” ? Phase-Stabilization • Gravity-coupling to Atomic Techniques Physics? fs Lasers• Generate Coherent uV and X-Rays • Sensitive Analysis of Human Breath Ultra-NonLinearity • Calibrate Astronomical Spectra – ExoPlanets? SuperContinuum
Hänsch group – Garching Hall group - Boulder
the Optical Comb - 39 years Later
Record-high quality factor Q ~ 2.5 x 1014 0.10
Fourier Limit: 1.8 Hz
0.08 0.06
Probe-time limited (~ 500ms)
0.04 0.02 0.00
3
P0(mF=5/2) Population
Boyd, Zelevinsky, Ludlow, Foreman, Blatt, Ido, & Ye, Science 314, 1430 (2006).
-6
-4
-2
0
2
4
6
Laser Detuning (Hz)
• Single trace without averaging • Est. instability ~ 1x10-15/√t
JILA Strontium Lattice Clock
With Lattice Intensity
With Density
Sr Lattice Clock at 1 × 10–16 Fractional Uncertainty by Remote Optical Evaluation with a Ca Clock A. Ludlow, G Campbell, ….
NIST T & F team, …. Jun Ye
Science 08
Metrological Standards Issues and Principles: Available in any country Acceptable cost Convenience of use – echelons of accuracy levels Precision and Repeatability valuable, even if a stable offset exists Accurate-enough, conforming to treaty standards
Independently Realizable Belongs to an elegant intellectual framework No Stake-Holder loses by the transition Funding Principle for the Research? Cost to users ~> research cost -- hmm Further research opens qualitatively new areas and possibilities? Research is a world-cooperation, driven by curiosity
WOW ! ~5 x10-5
NIST Cs Standard ~1 x10-16
Dissemination of the Standard
Optical Clock ~1 x10-17
laser
fRep
fs comb fRL Ref. Laser
Gauge-Block Interferometer
Length Metrology –
post 1983 – via the Metre = c/
Artifact Approach Corning’s ULE dL / dT T0 ~15 C
L/L ~1.8 x10-9 T2 ZERO linear Expansion
1987 JILA ULE bar
We can set T = T0 + 30 mK / T ~ 30 Hz /mK at 532 nm Drift-Rate ~ +10 mHz/s ~ 860 Hz/day (~200 days per atomic layer)
1987 JILA Cavity, ULE ~ 0 Expansion at 14.7 C Length change ~ 1 x10-12/day ~200 days to change by one atom’s diameter
JILA 1987 ULE Reference Cavity
Vacuum Shell, heated
Outer thermal shell, cooled
Mass center surface
L - L Mass center surface
Cancellation of Length Change, based on Symmetry! L + L Mass center surface
g linewidth 1 Hz sidebands 18 & 5.5
600 500
Power Spectrum
x10
Sub-Hertz Laser Linewidth -- on a Table Top !
-6
400 300 200
Delta Optical Frequency (Hz)
100
JILA/HallGroup_05
0 51.15
51.20
51.25 3
x10
5 cm Barger Cavity W Midplane Support Disk attached w RTV adhesive Add In wire bits Easily trim to -40 dB
3 PZT Shakers
Vibration-Insensitive Cavity Designs II Webster, Oxborrow & Gill Phys Rev A 75, 011801R 2007
Bergquist & Rosenband
Design for Zero along all 3 axes !
Chen, Hall, Ye 2006
Zero net change
X 5 x106
Vibration-Insensitive Cavity Designs
Each half sags 3.7 x10-8 /g Symmetric design 87 ppt/g net Asymm of 0.15 mm 1.1 ppt /g
LISA Frequency Reference L = 14 cm ULE 2006 Design, P.L. Bender
Thermal-Noise Limit in the Frequency Stabilization of Lasers with Rigid Cavities PRL 93, 250602 (2004) Kenji Numata,* Amy Kemery, and Jordan Camp Laboratory for High Energy Astrophysics NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
We evaluate thermal noise (Brownian motion) in a rigid reference cavity used for frequency stabilization of lasers, based on the mechanical loss of cavity materials and the numerical analysis of the mirror-spacer mechanics with the direct application of the fluctuation dissipation theorem. This noise sets a fundamental limit for the frequency stability achieved with a rigid frequency-reference cavity of order 1 Hz / Hz (0.01 Hz / Hz ) at 10 mHz (100 Hz) at room temperature. This level coincides with the world-highest level stabilization results.
Thermal-mechanical Position Noise Numata et al prl 93 2004
where One-sided power spectrum of av’g’d displacement noise
Coating loss
x
Acoustic mechanical loss of averaged position response to a local force
ULE, 24 cm cavity length, 8 cm diam.
Numata et al, prl 93 (2004)
Noise Frequency Density Results from NIST_B and VIRGO,
Compared with estimated from Numata’s Thermal Model x ~ f ~ 1/ Sqrt (f)
Beatnote betweeen two Lasers
tc
> 2s
Measur. Noise floor
Mirror thermal noise Accel-caused noise
Ludlow, Ye et al., Opt Lett 32 641 (2007)
Ludlow, Ye et al, OPTICS LETTERS March 15, 2007 / Vol. 32, No. 6 / p 641
Sr, 429 THz t = 0.48 s t scan = 30 s
Rio Laser
Phase Mod
Anti-RAM Q
S F
Frequency Servo
fsr
PDH
I I
Optical Sampler
Q
Anti-RAM Servos
PDH, fsr Det.
Sub-Hz Optical Frequency Reference System© Predicted Results, 12 cm cavity length, 1 s tau HCCH CO CO2
P(16) 1534.742 nm 0.004 W 0.x Hz R(3) 1563.149 nm 2.04 W 0.x Hz R(24) 1563.111 nm 1.54 W 0.x Hz
NICE-OHMS Detector
Jan’s Proposed Tools For the STAR Mission (Space-Time Anisotropy Research)
Multiple Redundant Cavities
Duplicate Atomic Clocks
Gas-Cell Frequency Standard CO or CO2 1500 nm telecom optics Ke-Xun Sun’s Multipass Idea for the Gas Cell
the HallLabs team welcomes your comments …
The Y2K HallLabs Team welcomes your comments …
Long-sheng Ma
jan
Jun Ye
Thanks for Listening • http://jila.colorado.edu/hall/ • http://HallStableLasers.com •
http://nobelprize.org/nobel_prizes/physics/laureates/2005/hall-lecture.html
• Jun - http://jila.colorado.edu/YeLabs/ • Lindy – http://Sci-TeksDiscoveryProgramforKids.org •
NIST - http://tf.nist.gov/timefreq/
•
50 Years of Lasers http://LaserFest.org
And now, to challenge and inspire a future generation of scientists … Moore Middle School, Jefferson County CO
http://Sci-TeksDiscoveryProgramforKids.org
The next generation looks promising to me ..
Grace 11 Catherine 9
John 5
Rocket Test Area Sandwich, Cape Cod, MA
Before Computers
2001: Advanced by Technology
Pete Bender, Venia Chebotayev and Siu-Au Lee help open the new and improved JILA HallLabs 1988
Lucent Technologies JILA spectrum
10 cm length
Detected Power (dBm)
-30 -40
Coupled Pow er 43 mW 26 mW 10 mW 3 mW input
-50 -60 -70 400
S. Diddams, D. Jones
600
800 1000 Wavelength (nm)
1200
Barger & Hall Prl 22 p4 (1969)
Understanding Saturated Absorption 1.0
1.0
0.8
0.8
0.6
0.6
Doppler’s Frequency-view of Maxwell’s Velocity Distribution
0.4 0.2
Population Density vs Velocity
0.4 0.2 0.0
0.0 -400
-200
0
200
-400
400
-200
0
200
400
150 1.0
100
0.8
1.0 50
Refractive Index vs Frequency --> A Gas Lens!
0.80
0.6
-50 0.6
Idealized Lamb’s Dip Response
0.4 0.2
-100 0.4 -150 0.2
0.0 -400
-200
0
200
400
Laser Power vs Frequency -400
-200
0
200
400
0
200
400
0.0 -400
-200
Fig. 1. Some milestones in the development of quantum metrology.
J Flowers Science 2004;306:1324-1330
Published by AAAS
– Thinking About Tools – +a few Sub-Random Remarks re: Science, Education, & More … John L Hall JILA University of Colorado Boulder CO 80309-0440
[email protected] http://jila.colorado.edu/hall/
F. A. Matsen Endowed Regents Lecture University of Texas, Austin 23 March 2011
~1940
Some of my Best Friends, in High School, were Radio Tubes
1950’s
~1943 - 1947
“ Receptions were unexpected and tough work, but somebody’s got to do it …. “
The Stockholm Concert Hall is Packed for the Ceremony
December 10, 2005
Stockholm December 10, 2005
