F. Marlow et al., OPTICAL 2ND-HARMONIC GENERATION OF (DIMETHYLAMINO)BENZONITRILE MOLECULES INCORPORATED IN THE MOLECULAR-SIEVE ALPO4-5, Journal of physical chemistry, 97(43), 1993, pp. 11286-11290
For (dimethylamino)benzonitrile (DMABN) in the straight Pores of the a
luminophosphate molecular sieve AlPO4-5, two components of the second
harmonic generation (SHG) have been found. One component of the freque
ncy-doubled radiation is polarized parallel to the length axis (z axis
, phi2 = 0-degrees) of the crystal and exhibits the maximum intensity
when the excitation beam has the same polarization. The second compone
nt, however, is polarized perpendicularly to the z axis (phi2 = 90-deg
rees) and shows the maximum efficiency for mixed excitation (phi = 45-
degrees). Obviously, different components of the hyperpolarizability t
ensor contribute to the resulting SHG. The reason for the different te
nsor elements are the two close-lying lowest excited states in DMABN h
aving transition dipole matrix elements perpendicular to each other. I
n contrast to molecular sieves loaded with p-nitroaniline which arc ab
le to mix waves of the same polarization only, for the DMABN-based mat
erials a mixing of waves of different polarizations is observed. This
is a promising property for phase-matching as a prerequisite for a tec
hnical application.