combining laser light with synchrotron radiation · 2014. 1. 18. · max born and emil wolf,...
TRANSCRIPT
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Combining laser light with synchrotron radiation
Part 2http://www.joachimschulz.de/laser/
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Literature
Orazio Svelto, “Principles of Lasers”, Plenum Press, New York (1989)
Wolfgang Demtröder, “Laser spectroscopy”, Springer, Berlin (2005)
Max Born and Emil Wolf, “Principles of optics”, Cambridge University Press (1999)
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Laser PrincipleLight Amplification byStimulated Emission of Radiation
Stimulated emission amplifies theexisting light wave
often within an optical resonator
active medium excited by:
flash lamp
discharge
laser
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Rate Equation
∣2 〉
∣1〉
d dt
=
Absorption stim. Emission
dN 1dt
=
spont.Emiss.dN 2
dt= P
pump Relaxation
−h
-N2 A21
+N2 A21
+N1 B12 ρ
-N1 B12 ρ
-N1 B12 ρ
-N2 B21 ρ
+N2 B21 ρ
+N2 B21 ρ
-N2R2
-N1R1
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Rate Equations
dN 2dt
=P−N 2 A−N 2−N 1B−N 2 R2
dN 1dt
=N 2 AN 2−N 1B −N 1R1
d dt
=N 2−N 1B−h
Lasing occurs only if N2>N1: Inversion
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Two level system
dN 2dt
=−N 2 A−N 2−N 1B
N 2N 1
=BAB
No inversion!No lasing!
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Three level system
Fast transition
1
2
3
dNdt
=W pN t−N −2BN−N tN A
Nt=N2+N1 N=N2-N1
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Four level system
Fast transition
1
2
3
dNdt
=W pN t−N −BN−NA
Fast transition0
N1=0
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Laser System at MAX II - I411
MAX II time structure
100 Mhz repetition rate: 10ns distance
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Laser System at MAX II - I411
desired properties:
chosen system:
Titanium dotted Saphire: 770-1000nm
laser dyes: 550- nm
wide tuning range
for absorption spectroscopy
for reaching different targets
continuous wave
no timing necessary
very high resolution
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Titanium:Sapphire laser
Sapphire Al2O3 dotted with Ti ionsA vibronic solid state laser
Fast transition
1
2
3
Fast transition
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Liquid Dye Laser
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O
N
N
O
O
Rhodamine
Liquid Dye Laser
Rhodamine 6G
absorps 532 nm
fluorescence555-585 nm
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Crystal pumped with 10 W VerdiFolded ring resonator
Gross wavelength selection withbirefringent filter
Optical diode chooses light direction
Ti:Sa Ring Resonator
Single mode selection by a setof Fabry-Perot-etalons
Scans and stabilization withBrewster plate and piezo-mirror.
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Verdi
Nd:YVO 4Neodymium Vanadate
Fundamental wavelength: 1064 nm
Intra cavity frequency doubling: 532 nm (2.33 eV)
Up to 10 W output power
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Neodynium dotted solid state lasers
Three 4f electrons
4I9/2
4I7/2
4F3/2
4F5/2 and others
1064nm Doubled to 532nm
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Laser System at MAX II - I411
1 mW alignment laser
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Alignment Procedures
Four degrees of freedom specifying alaser beam:
1 mW alignment laser
Position on the last mirror
Direction to the target
Spot size
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Adjusting the Beam Diameter
Kepler telescope
Galileo telescope
With pinhole: spacial filter
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Placing Windowswith Low Losses
vertical linear polarization
all objects in Brewster Angle
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90°
i
Brewster Angle
No reflection for light polarized inplane of incidence.
no longitudinal light waves
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Brewster Angle
For laser optics:
no reflection losses for the parallel polarization
used in polarization crystals
For classical optics:easy way to produce polarized light
defines the polarization of the laser mode
No reflection for light polarized inplane of incidence.
tan i=n1815 by David Brewster:
For Glass ~56°
90°
i
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Birefringence
n2different indexes of refraction
n1
n1=1.55for Quartz n2=1.54
retards one polarization with respect to the other
/2 -retarding plateflips linear polarization around
the principal axis/4 -retarding plate
produces circularly polarized light
n1=1.49for Calcite n2=1.66
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Maxwell's equations
∇×E=− B t
∇× H=J D t
∇⋅D= ∇⋅B=0
D=0 EP B=0 H M
Gauß' Law
Faraday's law Ampère's Law
No magnetic monopoles
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Polarization of the medium
D=0 EP
P=0 E
D=01 E= E
No birefringence:
More general case: χ is a tensor
Pi= ∑j=1,2 ,3
0ijE j
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Frequency doubling
D=0 EP
P=0 Ee 202E2
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More general case
Er , t =12 [
E r ,eitc.c. ]
PNL2 r , t =1
2 [P2 r ,2e2i tc.c. ]
Pi2= ∑
j ,k=1,2 ,30d i , j ,k
2 E jEk