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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors report on a novel phenomenon in calcium aluminosilicate glasses doped with Ce3+, Tb3+, and Pr3+ that after irradiation by an 800 nm femtosecond pulsed laser, the focused part of the laser in the glasses emits bright and long-lasting phosphorescence able to be clearly seen with the naked eye in the dark even one hour after the removal of the activating laser.
Abstract: We report on a novel phenomenon in calcium aluminosilicate glasses doped with Ce3+, Tb3+, and Pr3+. After irradiation by an 800 nm femtosecond pulsed laser, the focused part of the laser in the glasses emits bright and long-lasting phosphorescence able to be clearly seen with the naked eye in the dark even one hour after the removal of the activating laser. Moreover, by selecting appropriate glass compositions and species of rare earth ions, optional three-dimensional image patterns emitting long-lasting phosphorescence in various colors, including blue, green, and red, can be formed within glass samples by moving the focal point of the laser. Based on absorption spectra, the long-lasting phosphorescence is considered to be due to the thermostimulated recombination of holes and electrons at traps induced by the laser irradiation, which leave holes or electrons in a metastable excited state at room temperature.

160 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied ultrafast gain dynamics in InGaAsP optical amplifiers by means of pump-probe and cross-correlation measurements using 180 fs optical pulses.
Abstract: We have studied ultrafast gain dynamics in InGaAsP optical amplifiers by means of pump‐probe and cross‐correlation measurements using 180 fs optical pulses. The data show strong gain nonlinearities due to nonequilibrium carrier distributions and differ significantly from those observed in AlGaAs amplifiers.

160 citations

Journal ArticleDOI
TL;DR: In this paper, a femtosecond Ti:Sapphire laser, a femto-spectral dye laser, and a picosecond Nd:YLF laser were used for nonthermal in vitro ablation of bovine neural tissue.
Abstract: Nonthermal in vitro ablation of bovine neural tis- sue by using laser-induced optical breakdown generated by ultrashort laser pulses, with durations from 100 fs to 35 ps and pulse energies of up to 165mJ, has been investigated. The experiments were performed at wavelengths ranging from 630 to 1053 nm by using a femtosecond Ti:Sapphire laser, a femtosecond dye laser, and a picosecond Nd:YLF laser sys- tem. Tissue ablations have been achieved by focusing the laser beam on the surface of the tissue, to a spot diameter of 5- 20mm, resulting in the generation of a microplasma. Laser pulses from the Ti:Sapphire laser with 140 fs duration showed a two times higher efficiency of ablation than the longer 30 ps pulses from a Nd:YLF laser with an identical pulse energy. At pulse energies of 140mJ, single pass excisions deeper than 200mm were generated by the 140 fs pulses. In addition, the fluence at threshold of the ablation was found to be reduced for shorter pulse durations. For 3p slaser pulses at 630 nm, we measured the fluence at threshold to be about 5: 3J =cm 2 ; for 100 fs pulses from the same laser the experimental thresh- old was at 1: 5J =cm 2 . Histopathological examinations and scanning electron micrographs confirm the high quality of the excisions. No sign of significant thermal damage was ob- served.

159 citations

Journal ArticleDOI
TL;DR: In this paper, two different types of waveguide structures are fabricated in z-cut lithium niobate (LiNbO3) using focussed femtosecond pulses.
Abstract: Waveguide structures are fabricated in z-cut lithium niobate (LiNbO3) using focussed femtosecond pulses Two different types of waveguide structure are fabricated depending on the pulse energy used In the first, guiding occurs in regions directly surrounding a visible laser-damage region In the second, guiding occurs in a material modification region created at the focus High confinement guiding at 1550nm is demonstrated in the first type of waveguide but found to be temporary, thus indicating that at least part of the refractive index change is due to phenomena such as stress that are subject to relaxation Finally, the polarization dependent guiding properties of the structures are investigated

159 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of varying the dispersion on the pulsed continuum and noise effects in the continuous-wave continuum has been investigated using a nonlinear Schrodinger-equation model.
Abstract: Supercontinuum generation in a highly nonlinear, dispersion-shifted fiber at 1550 nm is discussed. Spectrum generation under both pulsed and continuous-wave conditions is considered. With a few meters of highly nonlinear, dispersion-shifted fiber and a femtosecond erbium fiber laser, an octave-spanning supercontinuum is demonstrated. Kilometer lengths of nonlinear fiber pumped by a continuous-wave Raman fiber laser are shown to generate a continuum with a bandwidth greater than 247 nm. A nonlinear Schrodinger-equation model is used to investigate the effect of varying the dispersion on the pulsed continuum and noise effects in the continuous-wave continuum.

159 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,403
20223,116
20211,239
20201,571
20191,715
20181,651