Widely tunable optical parametric oscillator with electrical wavelength control.

A LiNbO(3) optical parametric oscillator (OPO) pumped at 930nm shows a wide phase-matching curve. Each pulse produced by the OPO has a very broad natural linewidth, from 1480 to 1800 nm for the signal and from 1950 to 2550 nm for the idler. The emission wavelength is controlled thanks to an electrically tunable Fabry-Perot interferometer inserted into the OPO cavity.

Transient degenerate four-wave mixing in a saturable Nd:YAG amplifier: the effect of pump-beam propagation.

A transient model of degenerate four-wave mixing in saturable amplifiers is developed for calculation of the phase-conjugate reflectivity in the weak-probe-beam limit. Our model takes into account the laser amplification of all the interacting beams together with the wave-mixing process between the two counterpropagating pump waves. Experimental investigations are made in a flash-lamp-pumped Nd:YAG amplifier with nanosecond pulses at 1.

Tunable IR laser source with optical parametric oscillators in series.

A tunable IR laser source is described. A Q-switched Nd:YAG laser at 1.064 µm is used to pump two optical parametric oscillators (OPO's) in series.

[Pulsed emission in laser coronary angioplasty. Theoretical bases and experimental application].

The aim of this study was to evaluate the thermal diffusion of a pulsed laser beam in atheroma and to obtain in vitro vaporisation of the plaque without causing arterial wall lesions. A computerised mathematical model integrated 4 parameters: reflectivity, thermal conduction, the absorption factor and coefficient of diffusion. The thermal diffusion was shown to be dependent on the time constant and the temperature of vaporisation may be best attained with a short burst (200 ns) with a high peak power (6000 w).