M. Vogel
for the SPECTRAP collaboration
PRECISION SPECTROSCOPY ON HIGHLY CHARGED IONS
DOUBLE-RESONANCE SPECTROSCOPY IN HCI
Manuel Vogel
HCI level schemeHCI level scheme
F=5m =-4F
HFS
MW2F=4 m =-3F
m =-4F
m =-5F
......
MW1
h =g B MW F 0
typically 10 -10 Hz14 15
typically 10 -10 Hz9 10
H-like ion in external B-field: hyperfine levels are split into Zeeman sublevels
example: 209Bi82+ I=9/2
F=I+J, F=I-J J=1/2 (ground state)
Manuel Vogel
relationsrelations
nuclear g-factor gI
electronic g-factor gJ
atomic (ionic) g-factor gF
using this relation: measure any 2 numbers independently and get the third one free
e.g.
gI from NMR (but: diamagnetic shielding)gJ from Stern-Gerlach-Experiments
gF from double-resonance experiments
Manuel Vogel
known valuesknown values
+ a large number of gI from NMR
gJ
HFS
Manuel Vogel
double-resonance techniquedouble-resonance technique
idea: perform a laser-microwave double-resonance experimentand use the light from the optical transition as a probe for the Zeeman transitions
gF
gF‘
Manuel Vogel
case 1: only one gcase 1: only one gFF measured measured
we can use
to get either
or
I,F
I,F
small,well-known from theory
Manuel Vogel
case 2: two gcase 2: two gFF measured measured
if gF is measured for two different F, then we can simulaneously and independently get
and
(this only works for I>1/2)
Manuel Vogel
this meansthis means
...we can obtain electronic and nuclear magnetic moments (g-factors) simultaneously
with a relative accuracy of 10-7 or better (depending on the system)
...we are independent from diamagnetic shielding,i.e. shielding effects can for the first time be measured
and theory can be tested
BLIND SPECTROSCOPY
Manuel Vogel
optical spectroscopy by MW measurementoptical spectroscopy by MW measurement
idea: perform laser cooling on forbidden transition andprobe the effect by the corresponding motional frequency shift
in a magnetic bottle.
forbidden transition can be identified with a precision of better than 10-10
using only a single ionno optical detection
Manuel Vogel
axial laser cooling – magnetic bottleaxial laser cooling – magnetic bottle
z
initial resistive cooling,pick up,
rf frequencymeasurement
Manuel Vogel
frequency shiftfrequency shift
i.e. 10-6 to 10-5 shift
10-10 sensitivity
0 50 100 150 200 250 300 350 400 450 5001E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
B2=4mT/mm2
B2=40mT/mm2
RE
LA
TIV
E A
XIA
L F
RE
QU
EN
CY
SH
IFT
TRAPPING VOLTAGE [V]
B2=400mT/mm2
Manuel Vogel
sideband spectrumsideband spectrum
OPT OPT z+ OPT z+2 OPT z+3 OPT z- OPT z-2 OPT z-3
I[arb. units]
0.15
0.30
0.45
0.60
0.75
0.90
1.0
0.5
1.5
T[K]
2.5
6.5
15
"carrier"
red sidebandsblue sidebands
OPT OPT z+10 OPT z+20 OPT z+30 OPT z-10 OPT z-20 OPT z-30
I[arb. units]
0.02
0.04
0.06
0.08
0.10
0.12
10
0.5
15
T[K]
2.5
6.5
15
"carrier"
red sidebands
blue sidebands
Pb1+
Pb81+
Manuel Vogel
cooling ratescooling rates
Manuel Vogel
pro: estimated accuracy better than 10-10
needs only a single ionno optical detection system necessary
acceptable laser cooling times due to high detection sensitivity
can use existing/planned g-factor setup (replace MW by cooling laser)
Thank you for your attention
conclusionconclusion