Abstract

The fruitful analogy between beam diffraction in space and pulse dispersion in time has been applied first to the concept of temporal imaging using "time lenses".¹ A time lens is made of a modulator, which inprints a quadratic temporal law to the phase in the same way as a lens imprints a quadratic radial law to the phase of a beam. This device, which has found some applications to the measurement of ultrashort pulses,^2,3 should open the way to sophisticated pulse manipulation using the time equivalent of coherent optical processing methods.⁴ Basically, in such a device time propagation is realized using dispersive lines (see Fig. 1), but the best performances of actual modulators limit the time lens focusing to at best a few picosecond resolution. However, functions such as phase-correction do not require very strong focusing properties. Here, we develop a tíme analog of optical adaptive methods in the context of the chirped pulse amplification (CPA) technique,⁵ with the goal of finely tuning the phase using pure electronic means in order to compress at best the amplified pulses.

© 1996 Optical Society of America