C.A. Walsh
Stanford University
10 Papers
477 Citations
C.A. Walsh is an academic researcher from Stanford University. The author has contributed to research in topics: Dephasing & Picosecond. The author has an hindex of 8, co-authored 10 publications.
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Papers
Dynamics in low temperature glasses: Theory and experiments on optical dephasing, spectral diffusion, and hydrogen tunneling
TL;DR: In this article, temperature dependent photon echo (PE) and nonphotochemical hole burning (NPHB) measurements were reported on resorufin in three organic glasses: ethanol (1.5 −11 K), glycerol (1 −1 −25 K), and d−ethanol (1−1−11 K).
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A picosecond photon echo study of a chromophore in an organic glass: Temperature dependence and comparison to nonphotochemical hole burning
TL;DR: In this article, the first two-pulse photon echo experiments on a chromophore in an organic glass were reported, and the homogeneous electronic dephasing of resorufin in ethanol glass was measured from 1.5-11.4 K.
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Optical dephasing of chromophores in an organic glass: picosecond photon echo and hole burning experiments
TL;DR: In this article, the homogeneous optical dephasing time T 2 for the organic glass system resorufin in ethanol was measured by picosecond two-pulse photon echoes from 1.5 to 11.4 K.
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Inhomogeneous broadening of electronic transitions of chromophores in crystals and glasses: Analysis of hole burning and fluorescence line narrowing experiments
Abstract: A variety of nonphotochemical hole burning experiments are performed on the system pentacene (PC) in benzoic acid (BZA) crystals. These experiments and previously reported fluorescence line narrowing experiments are used to probe the nature of the inhomogeneous broadening of electronic transitions of chromophores in crystals and glasses. A microscopic model is presented which explains detailed results from both types of experiments. Two fundamental assumptions are made in formulating the model. First, there is a large degree of accidental degeneracy in the absolute energy distributions of the chromophores; i.e., molecules in different environments can have the same absolute energy. Second, this degeneracy is lifted when the electronic state is changed. Narrow band excitation of PC causes a well‐defined change in the PC’s local environment, producing a narrow spectral hole in the inhomogeneously broadened PC absorption origin and an antihole which is spectrally well‐separated from the PC origin. The micros...
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Homogeneous optical dephasing and line broadening processes in an organic glass: comparison of the temperature dependences of picosecond photon echo and hole burning experiments
TL;DR: The homogeneous optical dephasing times (T2) and the non-photochemical hole burning (NPHB) linewidths of resorufin in glycerol glass are reported from 1.1 to 25.5 K as discussed by the authors.
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