Imaging and focusing characteristics of partially coherent light pulses focused by a thin lens in nonlinear self-focusing media

For the quasi-steady-state (QSS) self-focusing case, the imaging and focusing characteristics of partially coherent light pulses (PCLPs) propagating through a thin lens in nonlinear self-focusing media are studied. The analytical formulae of the image distance and the image size are derived. It is shown that the time delay of the minimum and maximum of the image distance depends on the light spatial coherence, while the time delay of the maximum of the image size is independent of the light spatial coherence. On the other hand, the analytical formula of the focal length of PCLPs is derived. It is found that, when the value of the pulse peak power is fixed, a PCLP has more advantages to avoid the optical damage of materials as the incident distance or the thin lens focal length increases or the initial pulse width decreases.