Optical delay line dispersive and its use for the compression / extension of the laser pulses.

摘要

The invention relates to a dispersive optical delay line for frequency-modulated lightwave pulses, in particular laser waves. The delay line according to the invention comprises a first optical grating R1 and a second optical grating R2 which are parallel, separated by a distance d and located with a pitch (separation) a on the surface of a material of index N which is transparent to the light waves. An incident wave SIGMA is diffracted at an angle theta ' which is greater than the critical angle of refraction by transmission through the gratings R1 and R2, the angle of emergence of the second grating R2 also being equal to theta '. The values of the parameters N, theta ', a and d are chosen so that a delay time variation DELTA tR of the pulse through the line corresponds to a modulation band DELTA f of the pulse in a quasilinear range. Application to compression/expansion for obtaining laser pulses of high power or of very short duration. IMAGE