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.

Generation of 11-fs pulses from a Ti:sapphire laser without the use of prisms

Abstract: The generation of highly stable optical pulses as short as 11 fs from a Kerr-lens mode-locked Ti:sapphire laser containing no intracavity prisms is demonstrated. In the femtosecond oscillator design reported, novel dielectric mirrors provide broadband dispersion control for solitonlike pulse formation.

Femtosecond response of a single metal nanoparticle.

Abstract: The ultrafast nonlinear optical response of a single metal nanoparticle is investigated by combining a high-sensitivity femtosecond pump-probe setup with a spatial modulation microscope. Experiments are performed on 20 and 30 nm silver nanospheres, in situ characterized via their optical linear extinction spectrum. The measured transient response permits investigation of the electron-phonon energy transfer time in a single nanoparticle. Its dependence on the electronic temperature is quantitatively interpreted using the two-temperature model.

Programmable phase and amplitude femtosecond pulse shaping.

Abstract: We report programmable femtosecond pulseshaping using two commercially avaliable liquid crystal spatial light modulators (SLM). This allows generation of waveforms with arbitrary temporal phase and amplitude profiles within a 2.9 picosecond time window with features of less than 100 femtoseconds. Such waveforms suggest exciting prospects for the control of chemical behaviour.

Ultrafast spin-transfer torque driven by femtosecond pulsed-laser excitation.

Abstract: Spin currents have an important role in many proposed spintronic devices, as they govern the switching process of magnetic bits in random access memories or drive domain wall motion in magnetic shift registers. The generation of these spin currents has to be fast and energy efficient for realization of these envisioned devices. Recently it has been shown that femtosecond pulsed-laser excitation of thin magnetic films creates intense and ultrafast spin currents. Here we utilize this method to change the orientation of the magnetization in a magnetic bilayer by spin-transfer torque on sub-picosecond timescales. By analysing the dynamics of the magnetic bilayer after laser excitation, the rich physics governing ultrafast spin-transfer torque are elucidated opening up new pathways to ultrafast magnetization reversal, but also providing a new method to quantify optically induced spin currents generated on femtosecond timescales.

Femtosecond soliton propagation in fibers with slowly decreasing dispersion

Abstract: We obtain the adiabatic compression of femtosecond solitons in fibers with slowly decreasing dispersion (FSDD’s) and discover the effect of soliton pulse-width stabilization in FSDD’s. A theoretical model for the description of femtosecond-pulse propagation in FSDD’s is presented. The model takes into account higher-order nonlinear and dispersive effects in fibers. We present numerical simulations of a generalized nonlinear Schrodinger equation and the adiabatic soliton approximation theory as well. Good quantitative agreement between the theory and the experiments is seen. The effect of soliton pulse-width stabilization in FSDD’s is described as a result of the combined action of the third-order dispersion and Raman self-scattering effects. We also show the possibility of obtaining high-quality pulses with less than a 15-fs pulse width in the 1.6-μm spectral region by soliton compression in FSDD’s.