三苯甲烷染料的表面发光

SURFACE LUMINESCENCE OF THE TRIPHENYL METHANE DYES

用同步泵浦染料激光器与时间相关单光于计数技术相结合,测量了孔雀绿和结晶紫水溶液的表面发光。在激发波长为608nm时,除了观测到304nm二次谐波外,还观测到了由双光于吸收所产生的荧光。

The high peak power and continuous nature of the synchronously pumped CW dye laser allow the genetation of a sensitive and precise two-photon excitation response,and the wide tunability range allows acquisition of two-photon excitation spectra. It has been determined that the cavity dumped veision of the laser yields the best performance for t o-photon spectroscocy and offers the most versatile output method.The triphenyl methane (TPM) dye contains malachite green, brilliant green, crystal violet, ethyl violet and parafuchsin. These molecules have a propeller shape with the aryl groups rotated out of the molecular plane by about 320. They exhibit intense visible absorption bands, yet in fluid solutions are almost entirely non-fluorescenl, v ith quantum yields below 10-4.To measure fluorescence signals from solutions of TPM , the use of a time correlated single photon counting technique and a CW mode locked dye laser is considered very suitable.The excitation of a liquid sample was provided by the picosecond dye laser operating at 570nm-650nm.The pump light was polarized to provide components of the electric field both paiallel and perpendicular to the sample surface at a 70 angle of incidence. The polarization and amplitude of the signal were measured with appropriate polarizer, color fillers, monochromalor and photon counting technique with a cooled photomultiplier.In order to record two photon fluorescence shape, we adjusted the wavelength region of the monochromator.Malachite green and ciystal violet in water are selected for sample. The spectrum of malachite green in water shows visible absorption at 608nm and 420nm, and has also ultraviolet absorption bands at 312nm and 252nm. The spectrum of crystal violet in water shows visible absorption bands at 586 nm , and also has ultraviolet absorption bands at 300nm and 247nm.We have measured second haimonic signal of malachite green and crystal violet at wavelengh 304nm, and two photon fluorsescence. The two photon fluorescence spectrum is broad. We have found that second haimonic signal has good polarization, while the fluorescence has not any polarization.The signal of tv o photon fluorescence is significantly increased by increasing the concentration. The fluorescence signal arises from two step cxcilations from S0 to S1 and from S1 to S3 of malachite green, and from S0 to S1 and from S1 to S2 of crystal violet.