Institute of Organic Chemistry, University of Mainz, D-6500, Mainz, Federal Republic of Germany ...... Gordon, B. D. Bothwell, S. K. Gupta, S. Allen, P. Robin, E.
Universität Potsdam
Perspektiven Denkens 1 Donald Lupo, Werner historischen Prass, Ude Scheunemann, Andr´e Laschewsky, Helmut Ringsdorf, Isabelle Ledoux
Alexander Stache
Second-harmonic generation ...der scharffe Sebel ist meininAcker... Langmuir-Blodgett monolayers of stilbazium salt and phenylhydrazone dyes
first published in: Journal of the Optical Society of America B, 5 (1988) S. 300-307, ISSN 0740-3224 DOI 10.1364/JOSAB.5.000300 Postprint published at the Institutional Repository of Potsdam University: In: Postprints der Universit¨at Potsdam Mathematisch-Naturwissenschaftliche Reihe ; 94 http://opus.kobv.de/ubp/volltexte/2009/1740/ http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17401
Postprints der Universit¨at Potsdam Mathematisch-Naturwissenschaftliche Reihe ; 94 Mathematisch-Naturwissenschaftliche Fakultät
Second-harmonic generation in Langmuir-Blodgett monolayers of stilbazium salt and phenylhydrazone dyes Donald Lupo, W e r n e r Prass, and U d e S c h e u n e m a n n Hoechst AG, D-6230, Frankfurt, Federal Republic of Germany A n d r e Laschewsky and H e l m u t Ringsdorf Institute of Organic Chemistry, University of Mainz, D-6500, Mainz, Federal Republic of Germany Isabelle Ledoux Centre National d'Etudes des Telecommunications, Laboratoire de Bagneux, 196, avenue Henri F-92220, Bagneux, France
Ravera,
Received August 14,1987; accepted October 26,1987 The second-order nonlinear optical susceptibilities x of several phenylhydrazone and stilbazium salt dyes in Langmuir-Blodgett monolayers have been determined from second-harmonic-generation measurements. Three of the substances demonstrated x values greater than 10~ electrostatic units, although two of the three did not absorb light significantly at the second-harmonic wavelength. (2)
(2)
1.
6
INTRODUCTION
T h e high q u a d r a t i c n o n l i n e a r i t i e s of organic m a t e r i a l s , t h e i r wide t r a n s p a r e n c y r a n g e over t h e visible a n d t h e near-infrar e d s p e c t r u m , a n d t h e i r s h o r t r e s p o n s e t i m e associated w i t h t h e i r off-resonance n o n l i n e a r p r o p e r t i e s qualify t h e m for various a p p l i c a t i o n s in t h e field of optical signal processing, such as amplifiers, frequency c o n v e r t e r s , a n d m o d u l a t o r s . An increasing n u m b e r of organic m a t e r i a l s a r e now shown t o e x h i b i t s e c o n d - o r d e r n o n l i n e a r efficiencies t h a t a r e several o r d e r s of m a g n i t u d e higher t h a n in L i N b C > 3 . For example, t h e q u a d r a t i c n o n l i n e a r s u s c e p t i b i l i t y d-C;'°
H N-NH--N0 2
2
CH -(CH J 3
2
1 6
-COO-^-C^
o
0
CH ~(CH2)i5 3
CH=CH\(j-j£J-CH CH -(CH )i5 3
CH ~(CH )j517~0
I
3
3
CH=N-NH
2
NO,
(2)
2
CH -(CH ) -0 "G
'F
>G
u>,2u
r\
» V'
] ( E ) cos SQ, 2
w
(2)
4
w h e r e t h e function F i n c l u d e s factors r e l a t e d t o t h e t r a n s m i t t a n c e a n d reflectance of t h e various interfaces as a function of angles of i n c i d e n c e in t h e film for f u n d a m e n t a l or h a r m o n i c b e a m s Of or Op* , respectively, a n d in t h e glass s u b s t r a t e 0Q or 0G - F d e p e n d s also on t h e refractive i n d e x {n^) a t f u n d a m e n t a l ( h a r m o n i c ) frequencies in t h e film nf a n d in glass rig (nc ) a n d o n t h e angle 0. x is t h e n o n l i n ear coefficient of t h e L - B film of t h i c k n e s s I, t h e projection factors d e p e n d i n g on t h e t i l t angle 4> b e i n g t a k e n i n t o acc o u n t in t h e envelope function F. 8Q, describing t h e p h a s e difference b e t w e e n t h e t w o h a r m o n i c b e a m s , h a s t h e form 01
2u
W
01
2u
( 2 )
8Q = ==^- ( n
cos 0
2 w G
- n » cos 0
