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The unit of time and the
International System of Units
Mauricio López R.
Centro Nacional de Metrología CENAM
Out line
0. Introduction
1. The unit of time
2. The SI and the second
3. Frequency combs
4. Optical clocks
The unit of time and the
International System if units
La persistencia de la memoria, Salvador Dalí, 1931
0. Introduction
The unit of time and the
International System if units
The “new fire” icon
The unit of time and the
International System if units
Mapa de Henricus Martellus, latinizado de Heinrich Hammer Florencia (1489) Coloreado sobre papel, 300 x 470 mm.Fº 68 vº y 69 rº del Add. Ms. 15760 British Library, Londres
Harrison clock, 1736
The unit of time and the
International System if units
The world and the clocks
Alb
ert E
inst
ein
Max
Bor
n
The unit of time and the
International System if units
The Quantum Mechanics the tool to built atomic clocks
Light-matter interaction in the heart of the atomic clocks
Atomic PhysicsElectromagnetism /Optics
The unit of time and the
International System if units
El principio para usar transiciones atómicas como referencias para construir patrones de frecuencia fue propuesto por primera vez por I.
Isaac Rabi de la Universidad de Columbia en los años 1930s
The Nobel Prize in Physics 1944
I. Isaac Rabi
The unit of time and the
International System if units
The Nobel Prize in Physics 1989
Norman F. Ramsey
La invención del método de los campos oscilantes separados y su aplicación en los relojes atómicos
The unit of time and the
International System if units
NBS-1, 1952
The unit of time and the
International System if units
Caesium I, 1955 (NPL)Louis Essen
from one second in 300 years to about one second in 2000 years
The unit of time and the
International System if units
NBS-2, 1960
The unit of time and the
International System if units
USD 20,000
Atomichron (Atomic-Cesium) Clock, 1960National Company, IncMalden, Massachusetts
The unit of time and the
International System if units
1. The unit of time
The unit of time and the
International System if units
The SI unit of time is the second defined as follows:
"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom";
Definition
The unit of time and the
International System if units
First energy levels of the Cesio-133 atom
Electric Electron-nucleus
9192631770 Hz
F’=5F’=4F’=3F’=2
F’=4
F’=3
F’=4
F’=3
251MHz
200MHz
150MHz
1167MHz
+ Zeeman effect
11 subniveles9 subniveles7 subniveles5 subniveles
9 subniveles
7 subniveles
9 subniveles
7 subniveles
+
INTERACTION
EN
ER
GY
Spin-orbit
62P3/2
62P1/2
62S1/2
100
GH
z
+
CsV, NRC
The unit of time and the
International System if units
The unit of time and the
International System if units
CampoMagnético Constante (Campo C)
Contenedor con Cesio 133
Cavidad de RamseyCampo Magnético
Inhomogéneo (Campo B)
Campo Magnético Inhomogéneo
(Campo A)
FilamentoIncandescente
(Ionizador)
Detector
Generador deMicroondas
Lazo deamarre
Vacío
Ramsey Method
Alfred KastlerFrance
École Normale Supérieure, Université de Paris Paris, France b.1902d.1984
The Nobel Prize in Physics 1966
Descubrimiento y desarrollo de métodos ópticos para el estudio de resonancias de radio en átomos
The unit of time and the
International System if units
CampoMagnético Constante (Campo C)
Contenedor con Cesio 133
Cavidad de Ramsey
Generador deMicroondas
Lazo deamarre
Láser de bombeo
Láser de detección
FotodetectorVacío
Ramsey method + optical pumping
CsOP-1, CENAM
The unit of time and the
International System if units
NIST-7, NIST
The unit of time and the
International System if units
Steven Chu Claude Cohen-Tannoudji
William D. Phillips
USA France USA
Stanford University Stanford, CA, USA
Collège de France; École Normale Supérieure Paris, France
National Institute of Standards and Technology Gaithersburg, MD, USA
b.1948 b.1933 b.1948
The Nobel Prize in Physics 1997
Manipulation of atoms with light
The unit of time and the
International System if units
La Unidad de Tiempo y el
Sistema Internacional de Unidades
Optical molasesFriction type forces
ILx
y
z KT 1
IL
IL
NIST-F1
The unit of time and the
International System if units
2. The SI and the unit of time
The unit of time and the
International System if units
The unit of time and the
International System if units
The seven base units of the SI
Stabilized HeNe laser to a Iodine molecule transition used for the realization of the meter
c
The unit of time and the
International System if units
The second and the meter
Josephson effect
henfV 2
The unit of time and the
International System if units
The second and the Volt
0
2000
4000
6000
8000
10000
12000
14000
0 1 2 3 4 5 6 7 8 9 10 11 12
B (T)
xy ( )
0
500
1000
1500
2000
2500
xx ( )
Quantum Hall effect
2nehRH
The unit of time and the
International System if units
The second and the Ohm
Nuclear Magnetic resonance
00 21 B
The unit of time and the
International System if units
The second and the Tesla
3. Frequency combs
The unit of time and the
International System if units
The unit of time and the
International System if units
Frequency comb
The unit of time and the
International System if units
f
Optical Standard, fHg
f2n=f0+2nfrfn=f0+nfr 2
PLL 1
fr
Femtosecond laser + microstructure fiber
PLL 2
fr mf
f Hgr m = 106
Frequency combFrequency comb
Frequency combFrequency comb
4. Optical clocks
The unit of time and the
International System if units
Strontium ion trap at the NRC
Optical clocks
The unit of time and the
International System if units
1)(
0 Nff
Quantum limit for stability
Averaged time/ s
Alla
n de
viat
ion ()
The unit of time and the
International System if units
Energy levels and clock transition of the Mercury ion
The unit of time and the
International System if units
Trampa de iones de estroncio del NRC
Relojes Ópticos
The unit of time and the
International System if units
Some atoms to built optical clocks
The unit of time and the
International System of Units
Mauricio López R.
Centro Nacional de Metrología CENAM
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