Photon Echo and Time-Resolved Fluorescence Anisotropy Measurements of Organically Doped Sol-Gel Glasses

Abstract

We present time resolved measurements of homogeneous dephasing of organic dopants in inorganic sol-gel glasses. A variety of organically doped sol-gel glasses have been synthesized and their dynamics investigated by time-resolved photon echo and fluorescence anisotropy measurements. The homogeneous dephasing rate of the chromophore is determined from photon echo measurements at low temperature (T = 1.4 K), while thermally activated homogeneous dephasing mechanisms are investigated by temperature dependent photon echo measurements. Our results are contrasted with recent hole-burning experiments on doped sol-gel glasses. Aluminosilicate (ASE) and tetraethoxy silane (TEOS) glasses have been doped with rhodamine dyes, polyaromatics, cresylviolet, resorufin and a wide range of chromophores with different nonradiative electronic relaxation rates. A small list includes naphthalene (170ns), rhodamine 6G (2ns), Rose Bengal (500ps), stilbene (70ps), azulene (2ps), as well as quinizarin and chlorin. The visible absorption spectra of some organically doped sol-gel glasses is shown in Figure 1. The low temperature homogeneous dephasing rate for chromophores doped into TEOS and in ASE solgel glasses has been measured utilizing photon echo measurements, as shown in Figure 2.