SCIENCE | RESEARCH | Non-linear propagation and characterization of ultrashort laser pulses

Non-linear propagation and characterization of ultrashort laser pulses

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The propagation in air and other gases of the ultra-short ultra-intense pulses is purely non linear. The effects that appear are self-focusing, self-phase modulation and ionization of the medium. All these effects induce an increase of the spectral bandwidth of the pulse, opening a way to shorten the pulses towards their temporal limit (one cycle) by post-compression techniques. Our facility provides the possibility to develop new techniques to optimize the throughput energy in post-compression by manipulating the parameters of the input pulse. When using pulses with higher peak powers the Centro de Láseres Pulsados, in close collaboration with the University of Salamanca, has studied the non-linear propagation of special spatial distribution. Together, the CLPU and the University of Salamanca, have develop STARFISH (Spatio-Temporal Amplitude-and-phase Reconstruction by Fourier transform of Interference Spectra High-complex-beams), a new device to completely characterize the pulses in space.

By its services, the CLPU also provides tools to study ultrafast non-linear optics in crystals. Laser technology for producing amplified femtosecond pulses is usually based on the use of crystals that produce pulses in the near infrared. However, for many practical applications, short wavelengths (visible and ultraviolet) are required. Ultrafast non-linear processes in crystals (second-harmonic generation, sum-frequency generation, and optical parametric amplification) are the key tools for extending the spectral range of femtosecond pulses to new wavelengths.