Wavelengthhyphen;selective bleaching (``burning holes'') in the optical spectra of trapped electrons in organic glasses

摘要

This paper presents experimental evidence confirming that the broad optical absorption spectra of trapped electrons in glassy 3hyphen;methylpentane and methyltetrahydrofuran (MTHF) are convolutions of spectra of electrons trapped with different energies. Laser light of wavelengths near or to the red of theetminus;optical absorption maximum selectively depopulates electrons which absorb at the bleaching wavelength, thus creating a hole in theetminus;spectrum. Some additional indications as to the spectral properties of the individual electrons are given by the observations that (1) illumination ofetminus;produced in MTHF at 25deg;K with laser light to the blue of the absorption maximum results in nearly uniform bleaching throughout the spectrum; (2)etminus;produced in MTHF at 67deg;K and illuminated at 25deg;K with 1064 nm are bleached less efficiently thenetminus;produced at 25deg;K and have a low probability of being shifted to traps typical of mobile electron trapping at 25deg;K; (3) the spectra ofetminus;in MTHF are progressively redhyphen;shifted as the temperature at which they are produced is lowered from 97 to 10deg;K, and the resolution of the peaks observable in the spectrum produced at 72deg;K is lower for spectra ofetminus;produced at higher (97deg;K) or lower (25 and 10deg;K) temperatures. Some implications of these observations are discussed.