Nonlinear phase shift as a result of cascaded third-order processes
In centrosymmetric media, in addition to the third- and fifth-order nonlinearity, a cascaded [Formula Presented] nonlinearity contributes to the nonlinear refraction. The described effect takes place when the input beam is involved in nearly phase-matched third-harmonic generation. The nonlinear phase shift produced by this new cascaded nonlinearity is comparable to the nonlinear phase shift caused by the direct third-order nonlinearity [Formula Presented] A new analytical approach, low depletion approximation, was developed and used to study the cascaded third-order processes in the conditions of not very high third-harmonic conversion coefficients. At higher conversion coefficients the effect was studied by numerical simulations. The presence of a seeded third-harmonic wave gives another possibility of controlling the additional phase shift of the fundamental wave. The conditions for stationary copropagation of the fundamental and the generated wave are presented.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
Saltiel, S. (S.), Koynov, K. (K.), Tzankov, P. (P.), Boardman, A. (A.), & Tanev, S. (1998). Nonlinear phase shift as a result of cascaded third-order processes. Physical Review A - Atomic, Molecular, and Optical Physics, 57(4), 3028–3035. doi:10.1103/PhysRevA.57.3028