Intense Ultrafast Laser Pulses Research Articles

Focusing limits of intense ultrafast laser pulses in a high pressure gas: road to new spectroscopic source

As a result of focusing ultrafast Ti:Sapphire laser pulses in a gas, a plasma column is created. Its density does not exceed some limiting value as a result of the defocusing by the electrons resulting from multiphoton ionization and the involvement of high order nonlinearities. The spectrum of the radiation from the excited species in the column has little contribution from the plasma continuum and the line broadening is less than that of the spectra radiated from a plasma generated by a long laser pulse. Thus, the spectroscopic source obtained using short laser pulses is an excellent source for spectroscopy.

Self-bending of light

The supercontinuum light generated by oblique intense 100-fs ultrafast laser pulses was found to bend from the direction of the incident pulses. The emission direction of the anti-Stokes continuum that is due to self-phase modulation bends to one side, while the conical ring that is due to four-photon parametric generation bends to the other side. The self-bending of supercontinuum emissions is attributed to the spatial variation of the refractive index induced by the oblique pulse front, which causes the refraction of light for self-phase-modulation emission and the bending of the wave vector for the four-photon parametric generation.