Chirp measurement of multimode q-switched laser diode pulses by use of a streak camera and a grating monochromator.

We discuss spectrotemporal measurements of laser diode pulses performed with a streak camera and a grating monochromator to yield a precise evaluation of chirping effects in Q-switched multimode emissions. We experimentally illustrate several causes of errors, depending on the grating size and period as well as on the adjustment of the collimating lens at the monochromator output. An analytical formula is derived that allows us to relate the chirp amplitude to the inclination of the modal structures in the streak image.

White-light supercontinuum generation in normally dispersive optical fiber using original multi-wavelength pumping system.

We report on the experimental demonstration of a white-light supercontinuum generation in normally dispersive singlemode air-silica microstructured fiber. We demonstrate that the simultaneous excitation of the microstuctured fiber in its normal and anomalous dispersion regimes using the fundamental and second harmonic signals of a passively Q-switched microchip laser leads to a homogeneous supercontinuum in the visible range. This pumping scheme allows the suppression of the cascaded Raman effect predominance in favor of an efficient spectrum broadening induced by parametric phenomena.

Coherent measurement of short laser pulses based on spectral interferometry resolved in time.

We propose a new method for measuring the phase and the amplitude of a short laser pulse that is based on shearing interferometry in the spectral domain combined with time gating. The method has several features in common with spectral interferometry for direct electric-field reconstruction, in particular, fast and direct reconstruction of the phase. Accurate measurement of the phase added to an 80-fs pulse by a block of F4 glass demonstrates the technique.

Highly efficient phase locking and extracavity coherent combination of two diode-pumped Nd:YAG laser beams.

Intracavity phase locking and extracavity combination of the two emitted beams generated by a Nd:YAG laser longitudinally pumped by two fiber-coupled diode lasers are investigated. Phase locking is performed by a diffractive component located inside a confocal Fabry-Perot resonator. The coherent addition of the two synchronized beams in a single TEM(00) wave is made by a birefringent interferometer, with 96.

Wave-front reconstruction with a Fourier hologram in a phase-conjugating mirror oscillator.

A laser profile consisting of 113 coupled Gaussian waves is obtained in a cw oscillator by use of a BaTiO(3) crystal as both an amplifying medium and a phase-conjugating mirror. Mutual locking of Gaussian waves is performed by a pair of spatial f ilters. One of them is a high-resolution holographic component; the other is an opaque screen with identical circular apertures.