Two-Beam Modulation Instability in Noninstantaneous Nonlinear Media

I. Velchev, R. Pattnaik, J. Toulouse
2003 Physical Review Letters  
The development of modulation instability for two beams copropagating in a medium with noninstantaneous nonlinear response is investigated. The frequency dependence of the experimentally observed spectral broadening reveals the presence of two-beam coupling, resulting from the timedelayed Raman part of the third-order nonlinear susceptibility. We present an analysis of the experimental data, which yields a value of 271 fs for the lifetime of the optical phonons in silica fibers. To our
more » ... rs. To our knowledge, this is the first experimentally determined value for this important material parameter.
doi:10.1103/physrevlett.91.093905 pmid:14525186 fatcat:qpewe2juv5gsxm6rp2ll5me7su