Optical transverse excitation in quaterthiophene crystals by ultraviolet-visible internal and attenuated total reflection.
We report internal and attenuated total reflection of light at the interface between glass and a quaterthiophene crystal in the spectral region of the electronic transitions. The bands corresponding to the absorption of the a(u) and b(u) Frenkel exciton states are detected for different polarization of the incident light. In particular, the wave-normal vector being almost perpendicular to the b(u) transition dipole moment allows its transverse component to be accessed, whose excitation in conventional external reflection or transmission spectroscopies is forbidden.
Raimondo
L
L
Dipartimento di Scienza dei Materiali and INFM, Università di Milano Bicocca, Via Cozzi 53, I-20125 Milano, Italy. luisa.raimondo@mater.unimib.it
Laicini
M
M
Tavazzi
S
S
Borghesi
A
A
Spearman
P
P