Ultrashort Laser Pulse Phenomena, 2nd Edition

454 Pulse Shaping

pulse trains with well-defined phase relations are particularly interesting for

coherent excitation in optical spectroscopy and coherent (quantum) control of

photo induced processes in general.

8.3. PROBLEMS

1. A self-phase modulated pulse exhibits a spectrum that shows characteristic

modulations, cf. Fig. 8.2. Assume a Gaussian pulse of duration τ

p

and

peak intensity I

0

which is propagated through a material of length L and

nonlinear refractive index coefficient n

2

. Explain why for large SPM the

number of peaks in the spectrum is roughly given by φ

max

/π.(φ

max

is the

maximum induced phase shift which occurs in the pulse center.)

2. SPM of Gaussian beams is associated with self-focusing in a bulk material

with positive n

2

. Estimate the achievable ...