Wavelength and polarization dependence of spectral hole-burning efficiency in highly oriented J-aggregates

From the concentration dependence of the dichroic spectrum of highly oriented J-aggregates as well as the strong dependences of the spectral hole-burning efficiency on the burning wavelength and polarization, a system of cyanine dye aggregates was concluded to have a hierarchic structure of mesoscopic and macroscopic aggregates. The observed low efficiency, by a factor of 10−3, on the higher-energy side of the J-band is explained in terms of the inefficient conformational change in a macroscopic aggregate, which has a large enough size to be aligned fluid-dynamically by the centrifugal force in the process of the spin-coating method.