Topic
Femtosecond
About: Femtosecond is a research topic. Over the lifetime, 35106 publications have been published within this topic receiving 691405 citations. The topic is also known as: 1 E-15 s & fs.
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TL;DR: In this article, a comprehensive study of the UV photolysis of I3− in ethanol solution, using femtosecond time resolved transient transmission experiments, is presented, which indicates that with high probability, photoexcitation leads to direct formation of diiodide ions within 300 fs, which are vibrating coherently.
Abstract: We report a comprehensive study of the UV photolysis of I3− in ethanol solution, using femtosecond time resolved transient transmission experiments. We interpret our results to indicate that with high probability, photoexcitation leads to direct formation of di‐iodide ions within 300 fs, which are vibrating coherently. Through our experiments we have been able to determine that the time scales for vibrational dephasing, vibrational relaxation, and reorientation of the fragment ions are 400 fs, 4 ps, and 5 ps, respectively. Transmission signals at 620 nm and at 880 nm, which are above and below the λmax of the known absorption of I2−, oscillate at a precisely opposite phase. This and other results presented indicate that through the oscillations we are observing coherent vibration of the I2− photofragment. UV transient transmission experiments have been conducted in order to characterize the time scales for recombination. Preliminary results show that recombination takes place on several time scales. A fas...
170 citations
TL;DR: In this paper, femtosecond IR spectroscopy was used to detect injected electrons in colloidal TiO2 nanoparticles in the 1900−2000 cm-1 region.
Abstract: Transient infrared (IR) absorption of injected electrons in colloidal TiO2 nanoparticles in the 1900−2000 cm-1 region are measured by femtosecond IR spectroscopy. The direct detection of electrons in the nanoparticles with subpicosecond time resolution provides a new approach to study ultrafast interfacial electron transfer between semiconductor nanoparticles and molecular adsorbates. The dynamics of electron injection from sensitizers to nanoparticles and the subsequent back-transfer and relaxation dynamics of the injected electrons correspond to the rise and decay of the transient IR signal of injected electrons. Using this technique, the injection time for coumarin 343 sensitized TiO2 nanoparticles in D2O is determined to be 125 ± 25 fs. The subsequent decay dynamics of the injected electrons in nanoparticles are found to be different from conduction band electrons in a bulk TiO2 crystal.
170 citations
TL;DR: The transient absorption of nanocrystalline TiO2 films in the visible-to-IR wavelength region was measured under UV excitation at 266 nm in order to purposely generate plural electron−hole pairs in this paper.
Abstract: The transient absorption of nanocrystalline TiO2 films in the visible-to-IR wavelength region was measured under UV excitation at 266 nm in order to purposely generate plural electron−hole pairs in...
170 citations
TL;DR: In this article, the authors used a train of femtosecond laser pulses at 850 nm, in the transparent spectral region of bulk As40S60 glasses, to write waveguides by translating the glass sample along the optical axis of a strongly focussed laser beam.
170 citations
TL;DR: In this article, an ultra-intense, phase-stable terahertz laser field was applied to ferromagnetic cobalt films to imprint the laser's phase and field-strength characteristics onto the magnetization response.
Abstract: Off-resonant femtosecond magnetization dynamics are observed after applying an ultra-intense, phase-stable terahertz laser field to ferromagnetic cobalt films. The laser's phase and field-strength characteristics are directly imprinted onto the magnetization response. The off-resonant magnetization removes the speed limitation caused by the cooling process, providing new opportunities for ultrafast data storage.
170 citations