aspekte der modernen optik - tu-chemnitz.de · spektroskopie • absorption, emission von...
TRANSCRIPT
Prof. Dr. C. von Borczyskowski
Aspekte der modernen Optik
Vorlesung vom 20.05.2010
Spektroskopie
30.000
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-~0 . .11 ~~ .. • ~
3 GH~
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~
Spektroskopie • Absorption, Emission von elektromagnetischer Strahlung
(Optisch, Infrarot, Raman, Magnetische Resonanz, Photoelektronen), Dieelektrische Spektroskopie, Akustische Spektroskopie
• Quantenmechanischer Ansatz: (Eigen-) Energien,Wellenfunktionen, Übergangsmomente
• Bom-Oppenheimer Näherung: Separation von Elektron-, Kembewegungen (Schwingungen)
• Heisenbergsche Unschärfe-Relation
• Kohärenz
• Kontinuums Ansatz: Dielektrische Konstante, Absorption, Brechungsindex, Reflexion, Polarisation
• &ektrale-, zeitliche Auflösung, Emefindlichkeit, Mikroskopie
Molecular Orbitals
• Covalent bonds, lonic bonds, Hydrogen bonds
• Linear Combination of Atomic Orbitals (LCAO)
• Hybridisation
• Important Atoms: • H -1 ~ )2 • C z .. (2 /j);' 2 .>( (2 1') t:1 r:·
• N 2-,,(2"3); $){(2.p)
• 0 2 x ( 2 0»;' I-{ J.: (2/')
· s '2 K Lj Cl) ) 4 x ( sI')
• Metalls: Fe, Zn, Mg, Mn, ...
2
c ,
verschmolzenes getrennte Atome Atom Molekül
0_,
. >.
;, -~:.~" '
". .,'
I. I.ls
0 0. .' .~" '.. .....:····,· 0·''',. "'· 0". '.. ' '.'.-' . . ,.' . . .. ,'
, .. " ,.'
2p~
2p"
Q()-(JQ
2p,
Bild 11.3 Beziehung zwischen den Orbitalen getrennter H-Atome, von H2<~..foJckülen und den Orbitalen dcs verschmolzenen He-Atoms
t:::_ ,,. _ ..,'
x
z i, z
•
]
x
c. (a) spZ-HybridwellenCunktionen (Il) P. Wcllcllfuilklioll
Abb. 5·20. WellenfuI'ktlonen, die aus sp'-Hybridisierung resultieren.
(5.10)
,'.
." "
", :)U
-'li
• .,
'. , "1 ,.)'
Abb.2.26. Form d., blnd.nd.n und .nUbmd.nd.n MO Im lJ.nzoImoIoIr.iJl ,,'
E
-3 -2 -1 o 1 2 3
k =-2
k=-1 * k=1
f
* k=O
• • •
"Jablonski-Oiagramm"
E
Ionisierungsgrenze
••
. ...
.. -•.... •;
ISC., -rS V 1 IC
I
.-•• ISC
ssionAbs.
Phosphoreszenz
iJ
! IC. . . ~ .. I
j •t 11 .1
~ ~ --
Emi
.-~ - .. -
-
Singlettzustände Triplettzustände
S = 0 S = 1
Energy Scheme: Jabonsky Diagram
• LeAO
• Hybridisation
• 2-Electron Levels.
• Pauli Principle
• HOMO - Lumo Orbitals (Highest occupied molecular orbital - lowest occupied molecular orbitals)
• Born-Oppenheimer Approximation
• Vibrations: - Bending
- Stretchin~
- Scetal modes
- Phonon modes
1 i
~
I
E 1,5-105 u
0,5 -105
0,95-105
cm-1
0,05 0,1 0,15 0,2
R(nm) •
f----X------j
•••
•••
•••
Oprical properties of organic molecules and aystals
\ \\ \ ,I
\ \1 I
\ Ij
S,
-==~_._-- .....[d s,
T, c:
.;;;ou ~ ',,:.g I
u crossingu c: c:
u.~
- u ~ -0
Ö. u0
.0 ~
.=:! « '.t..
s, _ ............_.L.I......_z.__......:.:.,'~_=_';';'O;...._......~.·Lb=d
...
c:" ... )1l r:: k.
--++-.--HI-l--.............-+--- __ ~~ter~.:t:~ __
k, 'k Intersystem04- _
c: .g Co
o .0 ~
<: f I
f-
I I o I Iu 1 I c: o I I 1 u I I I ..... ~ . I I I öu
I I I';::;-o 1 I I c..-= Co I ! ! :;I I , .1
~ I I I '_' ,_. -= :..... I I I ~
I I I ~
11. {111 5",,;.'.:,·..I'...l.1.L.' _
-------------
---------- ----
o r0
o C\J
l() N
............... -" ~)-- -,
r:::. __
----~-r------- .... \
-1..,\
"-... Cl VI
-(l
~I
-
/ __ f'" _.... -_.... <:...--
--_...> ------' ...._----- ----====:.~-,-----
r-==::: -------- ........ ----.:::----.r~~ _
-o o
fr_-_-=~:::---
--====3._____ -S---
.... r,,,
c-::-------"'" I
-----::"
-r0 1 o x I::.
~(,l' 6.. ~c~:1r e_c"~SI" f!!-IUf~~ !'1 . I .
W Molekül Absorption0>
E 5
Benzol 2550 $.1) 1
Naphthalin 3150 $.CO Anthracen 3800 $.CCQ
3 Tetracen 4800 $.A A A ACCCO Pentacen 5800 $.
A A A A ACCC'CCJ 2
" Ci O'----'-------'-----'-----'-------'""-----.....J
500 500 400
Alnml -
\
\
CCCJ 00\
\
Ci
20000 25000 30000 135000 cm
--~
Zeitauflösung, Empfindlichkeit
• Femtosekunden - Monate (22 Größenordnungen)·
'"• Isolation
• Stabilität
• Detektoren
• "Effekt" - Modulation
• Kodierung
• Markierung
Spektrale Auflösung
• Hei.;enbergsche Unschärferelation
• Homogene Verbreiterung durch dynamische Prozesse
• Inhomogene Verbreiterung durch statische "Unordnung"
• Ensemble- Zeitmittelung
• Kl'häiente Verfahren, DOllPel-"Resonanz"verfahren
• S1!...ektralc Selektion Lochbrennen), Einzelm(Ilekültechniken
a.z(w-w')
I I 1
I 1
1
1 I 1
1- 1-)" I 1
1
I 114--/::,_1
1
---....::::::::....-----i~---=::::::::..--------=::::::=- w w'
0<:(
Lf)
t'CO Lf)CH 3
. HF H
100<:(3NAN
0In1 0 t'-Lf)NyN
0 CHHF 3
eH 3
5900 5500 ~
0<:(
M ZLO -0 <..9LO 0::: 0
0<:(
Lf)
r--. co Lf)
6500 6100 5700
WAVELENGTH (Al
z l')
0:: o
0<J:
' >t
lfl r--Cl) Lf)
,,.
lf)
Z W tZ
z o lf) lf)
,, .
2: w
I .
6500 """61OlJ:' , 5700
WAVELENGTH'(ÄI I'
FIGo.1. The absorption and laser7 indu.ced (at 5700 A) emission spectra of DMST in' durene at 2 K.
(frort) 1-1. de Vrie~ ohd 1).A. v./le.\"s;mo; 'P~y~, Re.II. le1t-. 3"/~1, IH~;'
I 0 ,
I I
E~
0 0 0
, ~ '-', .j
"-'\ . ...
~y.
0 I ~
E' -u M
~ V\
oS
~
'E u
0 L.() ..-
I
0 ~
1O or
'-J o •
~ 0
I
"'\ it
T-x
N., - - '-'
•• ~1-- - - - -0
0 :0 \.0 or
..::so
=
J -
-..---------E u >
-o -..0
CL N
I
~-~-~-~-------------------.R10
E c
o <D \()
o 10 \()
c:o U
co I U C-:l<:: -Q..:'::
C~~8 N(1) N~ o
(1) I{)
o-IC)
@
0 o (j
(\J
o
@
.(1)
0 .
1 2 3 4 1 3 2 4
---f~-'.....:...'" +~[>
~-~-f- *--+ A* B A s·
Austüusch - vV2chselwirkung
1 2 3 4 1. 2 3 4
-t-t -t; L> •
+i--i-f- -ft--i-A· B A sf-
Coulomb - VIechselwirkung
--
'r", rlo1eküle
$1 fv
1.( 0"//////////(/I'!mn - "
JAA(k)h_~V
J 1\B (k)I !
tlEf . tlEf+tlD f n n n
So I:mn 1 ,
'\I
I 4
~nregungsenergie fUr Bandverschiebung durch die Bandstruktur und Davydov
9ine MolekUlanregung Ww mit den anderen MolekUlen Aufspaltung
:im MolekUl n. im Kristall. +,+
~Ef = «.,f IH Icl> tlDnf
- L «'f~fml Ymn Ilf~ f m> E f (k) = 2J cos kb n n An n + AA
mfn -+ -+ -+ -+ -+ -+
+2JAB[cosk(a+b)/2 + cosk(a-b;- <Cf IH Ilf ». <'fmlfn IYmn Ilfm:fn >).n An n .,,~ c.... •ß..... .c.I~ ..-A'~" ~
- <
0.000 cm-1 <tlE~ <30.000 cm-1 tlDf typisch'" 1.CXXl cm -1 D3.vydov-Aufspaltung T1 typisch 10 cm-1 n
!
_11$, 100 an '
--
cl
bl
el
c,.\
I i
v lern-' I 17200
1060 939
't I,
".--< I
I I
.k.,,,, , :
I
16800
-2. I,, , I
I
r I
0-0
rTf'
16LOO
0-0
f ,j!/
l_ • .\ i-~, 1....(.:..-1/'
l_-Jl_ !
~olebur :11 cre
.1
'\ . . .I
• ''--- _// ......',1
"
Fig. 1. Excitatio spect um of free-base porphin (H-z P) .: T ·4.2 K: (a) in n-heptane (CIYstal) with broadband detection of l1uorescence; (b) in MTHF (gIau) with broadband detection of l1uoresccnce; (c) in MTHF (gIau) wlth narrowband detectlon of nuoresoence; (d) in MTHF (gIass) wlth a photo • chemlcal hole burnt I to the 0-0 transition and br ,adband d.tectlc:m oe l1u( rt'S<'"mce.'0
; .
c .'2 d. ~
o Vl
.D o
v, Vo
pholoproduc.t
v, v •
.. \ '. .-
__~,....-~ Ar· -
I
8
1---
nA 'mfler
! _.l'· ! .....;~ ~j' .. . ,sempie-
L. ..... SL. ..
('~% ?:= " cryostot
PO }-- leser
'-----I LI 5
n A m~ler monochromator
r ,I
I IHV II PM 1I -----, I),-'.11
I FP L - __________ .J- -- .
Hlchelson· wavemeter
H "'N--.-,(\ ~
,
\
(1 ) .r;-;:;lSlil[ VL:.-J
H H
0-0
(2)
(1) (2)
(1) (1)
(2)
(2)
.....J"-~~----.Ä..--J\.- .
16331 16266 14700 cm- 1
Single Moleeule Detection
-Principles of Optical Spectroscopy of Organic Moleeules and Nanoparticles
-Single Moleeule Detection Schemes
-Application to Moleeules
-Application to Nanoparticles
Single Emitter
Single Emitter in a Crystal at low T
~~ I
>0) ..... Q) c Q)
"
~
zero phonon line
10 MHz (10-3-10-4 cm- 1)
phonon wing
frequency
1several 10 cm
• probes nano-environment static & dynamic properties
• providies information on the members of an ensemble
• may show up new physical effects
- blinking - photobleaching in one step - bunching/anti-bunching of photons
Geordnetes Gitter
I~
Y
I~
homogene Linie
1
c .2- 2 \.. o Vl
.D « 3 .. wW,·W,·W,
amorphes Gilte
\ \ '- 1'\2\ r
\
.J.. -.... ""'-.j...
\ ~IL--.......
( /'"' ) I
c: o.-Q.... o 1/1 .Q «
inhomogene Linie
2
(0
. '. ...
j\'AVE)!"L:-1BER / cm- 1
16886 16883
'. ".
/ 1-;",,.. ~'.f'". , -
-' • I" ..,. ~ ~ . f'
C
B
.,:••~ • ..l...
. .' .. ",: .. . '\.... .~
30 GHz
f---------I
".' .;, . . .': " ..:
UJ Z
z~~ ~-
D :_'_i_:'-----'''----'__'_,_,_~._·._.
+-E\CITATIO.\ fREQCE.\CY
II 500 .-- '.:c..""... -----,
""-..,
o ~
_.,
o .. /../. .. \ . , 0.05 GH:
EXCITATION FREQ(jE~CY
4l:.~ X ~ SI .... Jf ~ y11t'-' Jf
/
.MWI I
,II Z I / 9(}o~.sLASER '" ,'~
/VI I I
~
1 S_o",---__
~hV
-
III
!lilllll~11
80
70
60 . -+--' c Q) 50 ü c Q) 40 ü Cf) Q) 30I.
0 :::J 4 20
10
0
Terrylene moleeule undergoing quantum jumps to the triplet state
plus jL'mps to another (frequency) state
o 1000 2000 3000 4000 Time / 100f.ls
C /\ 0.- ~I
..p.lI -l. ICO 'lJ- '---' Q) '\l L- I ~\ L- 0e 0 .-0 -~ ~'" C)t) 'lJ c......
Ü '---- ~ .-(J)0 e I \'-\ co..p.lI :::J ~II"J ...c::J lL.
"~ C) c 0
e:::( e (1)
...c 0Co)0 II C).- CC ...... C::J 0 .-CO ~ ..c :.;::; ...c
Q) (-J :.;::; CO Co) I- --...~ C - C I- oe:( Co) :::J
'-.->0 ~,
I (J) ..c Ü <r\:::; c 0 c
0 I 0e -+-' -+-' 0 ..c 00...... ...c CO ...c
0 0.. 0:: 0.. ~ I I I0
•
Densityn1atrix 5 - Level System
• Microwave - optical Blochequation
W -0 cos W t 11 L
-0 cos W r w22
W A cos wJ xxH/h W yy
-A cos wrJ. zzL W
Brown et al.
J. C. P. 1994
Correlationfunction
2 (l(t) l(t+-r;)) g (-r;)=
(1(t))2
\f)
"T
0 0 0 ......-I
0 0 ......-I
0 ......-I
......-I
--;;2:
......-I
· P 0
......-I
0 •
0
......-I
0 0 · 0 ......-I
0
•
'.\'
. . .~ . ..\
,~---~, " . . , ..... ;, '\,
~\ . . -."".!,,) ,
~"l
'>""'! • .X I>~ .... ~
'-Z~0,' ~
\ 4: .~_.S d:l
C <iT',.. ..... . ~
~ ~,
r.f.\ ~ •.,., ..... ~.
"''"
I I I I I 1 0 0\f) M \f) (".l \f) ......-I \f)"T 0. . . . · 0M (".l ......-I 0
T- (97 '3
;- ~500 C/J
!!! ':;;000 c i5 \500 (j
..2 1,000o.c: Q 500
o
".:; 600
.:J ~
(] 400 o
J! ~
200
Q~,11 o 0 \'
{'. lf\. ...-Q L~-0"II~1 -::- "ilJY·.~~~~ ~ .-> \.;:~~ t:'3 0 ",\.~..... .... . ."'"'' '~:.~.:::'.::.:<~
-../ 0 n 100-100 ,J
Loser detuning (MHz)
~
ö3 c c 220 ('j
..c u 200 .'Jj ~ ---c 180 ;:; 0 160 '-' u
140 ~.->-.
120on c Il)
- 100 c Il)
80 ~
u c 60 Il)
40u on Il) .... 0 20 ;:; ~
>.I., 0
•
•
0 5 10 15 20 25 30 Optical Frequency (GHz)
--I
vvv coun s s)
o.. .p..
N (Xl
(Xl 0
f-L N 0
NOL----===
~~ ~# 00 -CDCD AA c:(J) c: f-LN
--=::...-----.J
Correlation spectroscopy on rnolecules undergoing frequency shifts
System: Pentacene in p-Terphenyl
3.5
~
;:l 3 cd
'-" ....:ro 2.5......--c'"C)....- 2 .....N c 1.5<I.l N <I.l '" '"'0 1 MI ;:l-~
0.5 0 50 100
Zeit (s)
Autocorrelation function of fluorescence intensity yields typicaI correlation times:
150 200
. ~ '-'
NbJ)
I 0.9
0.8 / 0.7 r
0.6 0.5
0.4
0.3
1 J
0.001 0.01 0.1 1 10 100 1000 10000 "C (ms)
--
1;' c: l-'(
400
350"r 300
250
200
150 1800
1600 ~~
I• .-, 1400
1200
1000 0 200 400 600
f [5]
, ?....,~
---
---
1000
~800"3 =600Cl Cl
~
.-~itj200 .fl-= 0
5 55 Time (s)
1000 ~
~800'" ~600 Cl Cl ~
~ '~200
.fl 0..s 0
9000 .
3 ~
Cl Cl Cl Col '-'
~ .~
-.fl 0
1:1 0
200
Time lß
Time (s)
A
155105
B
15 20
C
400 600
I
T=4.2 K Dye moleeules2000
0 0 5 10 15 20 25 30
Control--:::J 600 I
cu '-'
>. 300+-'
In C 0
+-' c Q)
0 5 10 -Q) () ~ T=4.2 K c Q)
600 () In Q) 300 ..... a :::J 0 u- 0 5 10 15 20 25 30
2000 I T I 1.5 K
1.1. . ~ .L~~""H"Lt", ..._ J. •• ,- J)r"~"""'''''', If'~(Glas)
i i i i i i01 I I i I i i
0 5 10 15 20 25 30 Laser detuning (GHz)
Dynamics of t1uorescence intensity of single Inolecules
I. confocal images of single R6G moleeules (scan 1.2 x 1.2 ~lIn2)1
• temporal evolution of fluorescence intensity of single molecules
-·-r--------.-- --_._-,--- 2 0 I--~-----r-'-----'-1 9 I f
,. 5
,.
\YW ~ ~-~~~ o 5 20 25 20 30 40 50
o.o~1
l __.__ .~ ..L--_-----,--_..........l..--_~__-L_~__--'-_
tJs tl s
I
0.1 /-lm
550 600 650 700
Wavelength (nn1)
NATURE· VOl 369 . 5 MAY 1994
-soo
400
300
~ - 200 r, ,Ir" ...... . ......
8 100 VJ ....... c=',0,
U 18thmin
50
20th min
o
okrJrjM'
Average fürfirst 17
~
min
,....;.
550 600 650 700 Wavelength (nm)
Nitrogen Vacancy Defect (N-V centre)
- induced by electron iradiation (electron energy >300 keV)
- different charge states known
- weil studied by PL, RAMAN, ESR,ODMR
- high photostability
3E 1
?
> Q) E
" ~1A L{) C '<:tr--., ~C'J
I / /,......<0
3A --~t-~
90000
12500
10000Cl>....... rn
~ X FWHM =0.33Jlm~ 7500 ....... c ::J o 5000ü
2500
00 1 2 3 4 5
lateral position (~m)
Gruber et al. Science 276 (1997) 2012
I
single N-V centers fluorescence spectrum dynamics
1.21 Iin diamond......... BOO
(\:::J
~ 600 Q) P 1.1üc: 400 '\ -l1.l ~ ü eil 200 ),1 \l1.l "",..... 0 zero phonon line ~ :::J 10
l:i=
600 650 700 750 BOO~O 900 0.1 1.0 10
'T (ms)
wavelength (nm)
~ '"8 ~ lifetime ODMR spectrum
--L./=--_ ~~.100 ,I , I
0.0
1,05'-1
.....:::J
ro
l1.l ü c: 095 ~ , t1}
~ 0,90 o :::J- 0851 !,t
, 2840 2860 2880 2900 2920
monoexp.: ,th=11.6±O.7ns "
500 1000 1500mlcrowave frequency (MHz) decay / (20ps/channel)
80000 ,-------------::;;-;:====:;:::::;::=================]1,
optical Frequency (GHz)
Many 60 l 2,! 1. I Molecules-""""" ,,50! ,I I i
. t d40 I :[ ,...-...
~ 76750 i:: I ,1\ I Jil I ,1"1111o
'-" "* 10 ~~!~,~!J lr,~/M 11~'\~1 ~~~~I~I~W~IWf\~~r~!I~~ OLl~~'-~-~.2
"ü'j o 0.5 1 1.5 2 2.5 3C (!) +
~ 73500 ü c (!)
Molecule1.ü Cfl
~
g 70250 LL
"'= '=" Moleeule1
L-----'--_-.ll-:----'----~-;:--~-'---T-;:I;---L-~I;----,----------;J670000 0.4 0.8 1.2 1.6
Pulse Duration (J..ls)
• •
N ~
<I N ~
0
t Q) ;>,c . -Cl.. x
"'0 a.> Q) IC ~
Q) Q) ;> -=::::::: "'0 -Cl.. ..c CO -=:::::::0 .....E ..ClQ) .....(J)(J) Q)
::::Jc 0 :!::: iQ)W c E Q) -=::::::: Q)
c 0) CO(\j 0 Q) ::::J E -=::::::: ..Cl "'0C.- 0 E>..c Q)"'O(J) c (J) cl.... . c .Q) Q)Q)...... .
E c~
c - 0
W ~o -0 c c 0 .0 c-o CO
E -c :;::; E CO .....Q)
/- -
/
ES:::J l.... E ..... cc o .-c..> 0 c 0Q) ..... ._ C.Q.. >
Cf) Q)c
(J) ::::J 0 Q) c Q) 0)
e Q)
Q) -..c