  We demonstrate numerically a method of focusing two-photon field inside
one-dimensional random media. The approach is based on coherent control of
backscattering achieved by adaptive spectral pulse shaping. The spectral phases
of a femtosecond laser pulse are adjusted for the constructive interference of
its backward-traveling components, resulting in an enhanced reflection from
within the random system. A delayed forward-propagating second pulse overlaps
with the controlled reflection, increasing the inter-pulse multi-photon field
at a location determined by the delay between the two pulses. The technique is
shown to be robust against the variations of the disorder, and to work with
realistic pulse shaping parameters, hence enabling applications in controlling
random lasing and multi-photon imaging in scattering materials.
