U. Bogner

Electric-field-induced level shifts of perylene in amorphous solids determined by persistent hole-burning spectroscopy

Abstract Small shifts of the electronic levels of perylene in polyvinylbutyral by an electric field are probed by measuring the reversible filling of the center of a persistent spectral hole. The experimental results are explained by a linear electric-field dependence of the level shifts which is ascribed to the interaction of the perylene molecules with the amorphous matrix.

Electric field selective optical data storage using persistent spectral hole burning

The electric field domain is used as a storage dimension in optical data storage by persistent spectral hole burning. The memory locations in the electric field domain are addressed with the voltage applied to the sample consisting of the amorphous polymer polyvinyl‐butyral doped with the dye 9‐amino acridine. The information is written by burning spectral holes at different electric field strengths with a HeCd laser and read by detecting the presence or absence of holes with weak laser intensity.

Electric-field-induced spectral matrix-shift variations of perylene in non-polar matrices

We determined the electronic level shifts and the effective electric dipole moment differences of perylene in non-polar and polar matrices from the changes of spectral holes in an external electric field. The effective dipole moment differences of perylene in the non-polar matrices polyethylene, solid paraffin oil and n-octodecane are about one order of magnitude smaller than in the polar matrices polyvinylbutyral and butanol. The observed frequency shifts in the non-polar matrices, which depend linearly on the electric field strength, are attributed to electric-field-induced variations of the gas-to-matrix shift of the electronic levels of perylene.

Persistent spectral hole burning of dye molecules adsorbed on surfaces

Abstract Persistent spectral hole burning has been observed in the inhomogeneously broadened S 0 S 1 transition of isolated perylene and perylene butyric acid molecules adsorbed on various surfaces from vacuum and from solution. The measured widths of the spectral holes, the vibrational frequencies in the S 1 state, the inhomogeneous linewidths, and the Debye-Waller factors of the adsorbed molecules are discussed in comparison with the values of the dyes embedded in amorphous polymers.

Determination of the electron—phonon interaction of strongly inhomogeneously broadened optical transitions by electric-field- induced changes of persistent spectral holes

Abstract A method is presented for the direct measurement of the true phonon sideband and the Debye—Waller factor of strongly inhomogeneously broadened optical transitions. The method is based on electric-field-induced filling of the center of a spectral hole. It is aplied to fluorescence transitions of dye molecules in amorphous solids, in particular to perylene in polyvinylbutyral.

Laser beam modulator and pulse former with an adjustable transmission‐voltage characteristic provided by persistent spectral hole burning

The transmission of a polymer film doped with dye molecules is modulated by voltage‐induced changes of the population in the center of a persistent spectral hole. It is demonstrated that the transmission versus voltage characteristic of the sample is adjustable to the requirements of the desired application by applying a selected time‐dependent voltage during spectral hole burning. Various characteristic curves have been tailor made and used for modulation and pulse forming of laser beams.

Electric field effects on persistent spectra holes: perylene in the Shpol'skii matrix n-heptane

Abstract Upon application of an electric field the spectral holes burned in different lines of the Shpolskii multiplet of the centrosymmetric molecule perylene in the non-polar matrix n -heptane were splitted in two components, while the holes in the continuous background between the lines were broadened. The splitting and broadening were found to increase linearly with the electric field strength. The experimental results are discussed in terms of electric-field-induced variations of the gas-to-matrix shift of the electronic levels of perylene, which is caused by the dispersion interaction.

Subnanosecond response time of a laser beam modulator based on persistent spectral hole burning

Electric-field-induced changes of a persistent spectral hole vary the transmission of a perylene doped polymer film used in a light-guiding configuration for the modulation of laser light. From the comparison of the measured transmitted laser power with a computer simulation we conclude that the response time is less than 300 ps.

Barrier crossing of H− and D− ions in CS(2) centers of hydrogenated SrF2:Pr3+

Abstract By laser selective excitation and thermal cycling techniques, we studied photo-transformations and their reverting processes for the CS(2) center present in deuterated and hydrogenated SrF2:Pr3+ crystals. Excitation with a narrow-band laser produces persistent spectral holes and a spectral re-distribution within the inhomogeneously-broadened absorption line. Using a laser with a linewidth comparable to the absorption line we measured both reversible polarized-bleaching reorientations and photo-induced formation of a distinct photoproduct center. We measured the reverting temperatures of both the reoriented centers and photoproduct centers. The temperature for reverting CS∗(2) photoproduct centers is 82 ± 3 K, whereas the temperature for reverting reorientated CS(2) centers is 101 ± 3 K. The reverting temperatures for reorientation are identical for the H− and D− varieties of this center. These results are explained by barrier crossing in asymmetric double-well potentials and the respective barrier energies are estimated.

Heat-pulse propagation in polymers detected by selectively laser-excited dye molecules

Abstract Anti-Stokes sideband spectroscopy and phonon-induced changes of a spectral hole in the strongly inhomogeneously broadened transition of dye molecules in polymers have been applied to the study of heat-pulse propagation in thin polymer films with high time resolution. The measurements indicate a diffusive propagation and a Planck frequency distribution of the phonons in the polymer.